Base station apparatus and method for monitoring travel of a mobile vehicle

[0002] This document claims priority to U.S. Provisional Patent Application entitled “BASE STATION APPARATUS AND METHOD FOR MONITORING TRAVEL OF MOBILE VEHICLE,” assigned serial No. 60/122,482 and filed on Mar. 1, 1999. This document also claims priority to and is a continuation-in-part of copending U.S. Patent Application entitled “SYSTEM AND METHOD FOR ACTIVATION OF AN ADVANCE NOTIFICATION SYSTEM FOR MONITORING AND REPORTING STATUS OF VEHICLE TRAVEL,” assigned Ser. No. 09/163,588 and filed on Sep. 30, 1998, and U.S. Patent Application entitled “ADVANCE NOTIFICATION SYSTEMS AND METHODS UTILIZING A COMPUTER NETWORK,” assigned Ser. No. 08/852,119, and filed on May 6, 1997. Application Ser. No. 08/852,119 claims priority to (a)-(d) hereafter and is a continuation-in-part of (b)-(d) hereafter:

[0003] (a) provisional application entitled, “ADVANCE NOTIFICATION SYSTEM AND METHOD UTILIZING A COMPUTER NETWORK,” filed Mar. 7, 1997 by M. K. Jones and assigned serial No. 60/039,925;

[0004] (b) nonprovisional application entitled, “ADVANCE NOTIFICATION SYSTEM AND METHOD UTILIZING PASSENGER-DEFINABLE NOTIFICATION TIME PERIOD,” filed May 2, 1995 by M. K. Jones and assigned Ser. No. 08/434,049, now U.S. Pat. No. 5,623,260 to M. K. Jones that issued on Apr. 22, 1997;

[0005] (c) nonprovisional application entitled, “ADVANCE NOTIFICATION SYSTEM AND METHOD UTILIZING VEHICLE PROGRESS REPORT GENERATOR,” filed May 2, 1995 by M. K. Jones and assigned Ser. No. 08/432,898, now U.S. Pat. No. 5,657,010 to M. K. Jones that issued on Aug. 12, 1997; and

[0006] (d) nonprovisional application entitled, “ADVANCE NOTIFICATION SYSTEM AND METHOD UTILIZING PASSENGER CALLING REPORT GENERATOR,” filed May 2, 1995 by M. K. Jones and assigned Ser. No. 08/432,666, now U.S. Pat. No. 5,668,543 to M. K. Jones that issued on Sep. 16, 1997;

[0007] where documents (b), (c), and (d) are each a continuation-in-part of the application entitled “ADVANCE NOTIFICATION SYSTEM AND METHOD UTILIZING A DISTINCTIVE TELEPHONE RING,” filed Mar. 20, 1995 by M. K. Jones and assigned Ser. No. 08/407,319, now abandoned, which in turn is a continuation-in-part of an application entitled “ADVANCE NOTIFICATION SYSTEM AND METHOD” filed May 18, 1993 by M. K. Jones et al. and assigned Ser. No. 08/063,533, now U.S. Pat. No. 5,400,020 to M. K. Jones et al. that issued on Mar. 21, 1995. All of the foregoing applications and patents are incorporated herein by reference.

[0008] 1. Field of the Invention

[0009] The present invention generally relates to data communications, tracking, and messaging systems and, in particular, to a vehicle monitoring apparatus and method for use in connection with a tracking system or an advance notification system that both tracks vehicles and gives advance notice of impending arrivals of vehicles at particular stops. The vehicle monitoring apparatus and method of the present invention essentially track and report the status of a mobile vehicle as the vehicle travels.

[0010] 2. Related Art

[0011] For at least the purposes of allowing advance preparation and scheduling, it would be desirable to know, in advance and with substantial accuracy, the expected arrival time of a mobile vehicle (for example but not limited to, a bus, truck, train, ship, plane, aircraft, etc.) at a particular location, such as a stop along a predefined route or a destination.

[0012] For example, consider a commercial bus station. A person picking up a friend or relative at the commercial bus station usually calls the bus station to find out the approximate arrival time (information which is oftentimes unavailable or unreliable) and/or arrives at the bus station prior to the scheduled arrival time of the bus, hoping that the bus is not significantly delayed. With knowledge of accurate arrival information in advance, adjustments can be made to one's schedule to avoid having to wait extended periods for a vehicle.

[0013] Another example involves school children that ride school buses. The arrival times of school buses at scheduled stops can be significantly affected by many factors, such as maintenance problems, rush hour traffic, congested urban/suburban conditions, and adverse weather. As a result, school children typically wait at bus stops for long periods of time, oftentimes in adverse weather conditions, on unlit street corners, or in hazardous conditions near busy or secluded streets. An advance notification system that would inform the students of the school bus's proximity would be desirable so that students can avoid having to wait for the school bus at the bus stop for extended time periods.

[0014] Yet another example involves the commercial overnight package delivery industry, wherein packages are delivered many times on a tight schedule. Customers oftentimes wait on delivery of important time-critical packages, not knowing precisely when the delivery will occur. An advance notification system that can inform a customer of the precise arrival time of a delivery vehicle would be desirable in order to improve customer service and to allow the customer to better schedule a pickup of a delivered item.

[0015] In order to alleviate the arrival time problem in the context of school buses, student notification systems have been developed in the past that use a wireless transmitter on each bus and a compatible wireless receiver inside each student home. U.S. Pat. No. 4,713,661 to Boone et al. and U.S. Pat. No. 4,350,969 describe systems of this type. When the school bus and its on-board transmitter come within a certain range of a particular home receiver, the transmitter sends a signal to notify the student that the school bus is nearby. While such notification systems work satisfactory under certain circumstances, nevertheless, these systems are limited by the range of the transmitters and require the purchase of relatively expensive receivers for each student. In addition, such systems provide little flexibility for providing additional information to the students, such as notifying them of the delayed arrival of a bus or alternative bus route information.

[0016] Thus, a heretofore unaddressed need exists in the industry for better systems, apparatuses, and methods for accurately tracking and/or reporting the status of mobile vehicles as the vehicles travel.

[0017] The present invention overcomes many inadequacies and deficiencies of the prior art, as discussed hereinbefore. In general, the present invention provides an automated computer-based apparatus and method for efficiently monitoring travel of a vehicle along a predetermined route. The apparatus and method may be used in connection with, for example but not limited to, a tracking system or an advance notification system.

[0018] In a broad sense, the automated computer-based apparatus of the present invention includes a communications device and a base station manager located at a base station. The base station manager tracks locations of a vehicle traveling along a predetermined route by communicating with a vehicle computer-based apparatus on the vehicle. The vehicle computer-based apparatus determines the current location of the vehicle as the vehicle travels and transmits information pertaining to the vehicle's location to the base station manager via the communications device. The base station manager determines when the vehicle is a predefined proximity relative to a predetermined location and transmits a notification message to a user so that the user is notified in advance of an impending arrival of the vehicle at the predetermined location. The predefined proximity can be a predefined time that the vehicle is from the predetermined location, can a predetermined distance from the predetermined location, or can be a specific location on earth.

[0019] In accordance with another feature of the present invention, the base station manager assumes that the vehicle is traveling along the predetermined route according to a predefined schedule unless notification is received from the vehicle computer-based apparatus. If notification is received from the computer-based apparatus, the base station manger determines the current location of the vehicle based on the received notification. Otherwise, the base station manager determines the current location of the vehicle based on the predefined schedule.

[0020] In accordance with another feature of the present invention, the communications device located at the base station may be configured to selectively communicate data with the vehicle computer-based apparatus via either the voice channel and/or a control channel of a cellular network. In communicating over the control channel, the communications device can alter a mobile identification number (MIN) or an electronic serial number (ESN) to transfer data, or the communications device can append data to the end of a feature request. Use of the control channel can significantly reduce costs.

[0021] The present invention has many advantages, a few of which are delineated hereafter, as mere examples.

[0022] An advantage of the present invention is that travel of a plurality of vehicles can be easily and effectively monitored.

[0023] Another advantage of the present invention is that a user can be automatically notified of the impending arrival of a vehicle at a predetermined location when the vehicle is within a predefined proximity of the predetermined location.

[0024] Another advantage of the present invention is that travel of a vehicle can be remotely monitored with minimal communication between devices on the vehicle and the remote monitoring device.

[0025] It should be emphasized that the features of the present invention can be employed for tracking and reporting on the status of virtually any type of mobile vehicle, or mobile object, including but not limited to, a bus, truck, train, ship, plane, aircraft, human being, animal, etc.

[0026] Other features and advantages of the present invention will become apparent to one skilled in the art upon examination of the following detailed description, when read in conjunction with the accompanying drawings. It is intended that all such features and advantages be included herein within the teachings of the present invention, as set forth herein and as sought to be protected by the claims.

[0027] The invention can be better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other, emphasis instead being placed upon clearly illustrating the principles of the invention. Furthermore, like reference numerals designate corresponding parts throughout the several views.

[0028] FIG. 1 is a block diagram illustrating a vehicle tracking system employed within the context of an advance notification system in accordance with the preferred embodiment of the present invention.

[0029] FIG. 2 is a block diagram illustrating an implementation of the vehicle control unit of FIG. 1 in accordance with the preferred embodiment of the present invention.

[0030] FIG. 3 is a block diagram illustrating a computer implementing the functionality of the vehicle manager of FIG. 1 in accordance with the preferred embodiment of the present invention.

[0031] FIG. 4 is a block diagram illustrating a computer implementing the functionality of the base station manager of FIG. 1 in accordance with the preferred embodiment of the present invention.

[0032] FIG. 5 is a flow chart illustrating the architecture, functionality, and operation of the vehicle control unit of FIG. 2 while the vehicle control unit is creating the vehicle schedule of FIG. 3.

[0033] FIG. 6 is a flow chart illustrating the architecture, functionality, and operation of the vehicle control unit of FIG. 2 while the vehicle control unit is tracking the vehicle of FIG. 1.

[0034] FIG. 1 depicts an automated vehicle tracking system 10 illustrating the principles of the present invention. As shown by FIG. 1, the vehicle tracking system 10 is preferably employed within the context of an automated advance notification system 12 that automatically provides advance notice of impending arrivals of vehicles at destinations or other locations. However, it is possible to utilize the vehicle tracking system 10 independent of the notification system 12 in applications where the transmission of a notification message (which will be described in further detail hereinafter) is not desired.

[0035] As depicted in FIG. 1, a vehicle control unit (VCU) 15 is disposed on a mobile vehicle 17, which is capable of transporting the VCU 15 over various distances. For example, vehicle 17 can be any movable object or thing, including but not limited to, an automobile, an airplane, a train, a boat, a human being, an animal, or any other thing capable of moving across or through the Earth's surface and/or atmosphere.

[0036] In the preferred embodiment, the vehicle 17 is a delivery vehicle for delivering items to a destination or for picking up items at a destination. Please note that items can include many various types of packages or goods to be delivered or picked up. Furthermore, items can also include persons to be picked up or delivered, such as when a bus picks up and/or delivers passengers at different bus stops. Preferably, the vehicle 17 travels along a predetermined route in making its deliveries, and the vehicle 17 may make numerous stops along its route in order to deliver or pick up different items at different locations.

[0037] Vehicle Control Unit

[0038] A more detailed view of the VCU 15 is depicted in FIG. 2. A sensor 18 within VCU 15 is configured to determine the location of the sensor 18 relative to a predetermined reference point. In the preferred embodiment, sensor 18 is a global positioning system (GPS) sensor, although other types of positioning systems and/or sensors are also possible. For example, other types of sensors 18 that may be used to implement the principles of the present invention include, but are not limited to, sensors 18 associated with GLONASS, LORAN, Shoran, Decca, or TACAN. The GPS sensor 18 of the preferred embodiment is configured to receive signals 21a-21cfrom a plurality of GPS satellites 23, and as known in the art, sensor 18 is designed to analyze signals 21a-21cin order to determine the sensor's location or coordinate values relative to a predetermined reference point. For example, in the preferred embodiment where sensor 18 is a GPS sensor, the sensor 18 determines the sensor's location values relative to the Earth's zero degree latitude and zero degree longitude reference point, which is located at the intersection of the Equator and the Prime Meridian. U.S. Pat. No. 5,781,156 entitled “GPS Receiver and Method for Processing GPS Signals” and filed on Apr. 23, 1997 by Krasner, which is incorporated herein by reference, discusses the processing of GPS signals 21a-21creceived from GPS satellites 23 in order to determine the sensor's location values. Since the sensor 18 is located within VCU 15, the location values determined by the sensor 18 are assumed to match the location values of the vehicle 17 and the VCU 15.

[0039] It should be noted that the term “location value” shall be defined herein to mean any value or set of values that may be used to determine a location of a point on the Earth or within the Earth's atmosphere. This value may be a coordinate value (i.e., grid value), polar value, vector value, or any other type of value or values known in the art for indicating locations of points.

[0040] Sensor 18 is designed to transmit a signal 27 to vehicle manager 29 indicating the vehicle's current location values. Vehicle manager 29 is configured to receive signal 27 and to monitor the location of the vehicle 17 over time by processing multiple signals 27. The vehicle manager 29 can be implemented in software, hardware, or a combination thereof. In the preferred embodiment, as illustrated by way of example in FIG. 3, the vehicle manager 29 of the present invention along with its associated methodology is implemented in software and stored in computer memory 30aof a computer system 31a.

[0041] Note that the vehicle manager 29 can be stored and transported on any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “computer-readable medium” can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer readable medium can be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a nonexhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), an erasable programmable read-only memory (EPROM or Flash memory) (magnetic), an optical fiber (optical), and a portable compact disc read-only memory (CDROM) (optical). Note that the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory. As an example, the vehicle manager 29 may be magnetically stored and transported on a conventional portable computer diskette.

[0042] The preferred embodiment of the computer system 31aof FIG. 3 comprises one or more conventional processing elements 32a, such as a digital signal processor (DSP), that communicate to and drive the other elements within the system 31avia a local interface 33a, which can include one or more buses. Furthermore, an input device 34a, for example, a keyboard or a mouse, can be used to input data from a user of the system 31a, and screen display 35aor a printer 36acan be used to output data to the user. A disk storage mechanism 37acan be connected to the local interface 33ato transfer data to and from a nonvolatile disk (e.g., magnetic, optical, etc.). It should be noted that input device 34a, display 35a, printer 36a, and disk 37aare optional and are not a part of the preferred embodiment, although other embodiments may include these features.

[0043] The vehicle manager 29 is preferably configured to maintain a predefined schedule 39a, referred to herein as the “vehicle schedule 39a,” within memory 30a. The predefined vehicle schedule 39acorresponds with a route of travel for the vehicle 17. In this regard, the predefined vehicle schedule 39astored in memory 30aincludes data defining locations along the vehicle's intended route of travel. Furthermore, each location is associated with a particular time value indicating when the vehicle 17 is expected to reach the associated location. Each time value along with its associated location defines an entry in the vehicle schedule 39a.

[0044] In the preferred embodiment, the time value corresponds to the estimated amount of time that should lapse between the time that the vehicle 17 starts its intended route and the time that the vehicle 17 reaches the associated location along the route. However, other time values may be used without departing from the principles of the present invention. For example, the time of day that the vehicle 17 is expected to reach the associated location may be used. Any time value that indicates when the vehicle 17 is expected to reach the associated location is sufficient for the purposes of the present invention. However, for illustrative purposes, the present invention will be discussed hereinafter assuming that the time values in the entries of the vehicle schedule 39aconform to the preferred embodiment (i.e., that the time values represent the amount of time that should lapse between the time that the vehicle 17 starts its intended route and the time that the vehicle 17 reaches the associated location along the route).

[0045] The vehicle manager 29 is configured to monitor the amount of time that lapses as the vehicle 17 travels along the vehicle's route. For example, the computer system 31acan include a clock 38athat indicates the time of day. In this situation, the vehicle manager 29 is configured to store the time value of the clock 38awhen the vehicle 17 begins the route. Therefore, the vehicle manager 29 can determine the amount of time that has lapsed since the start of the route by comparing the current time value of the clock 38aversus the stored time value for the start of the route. Alternatively, the clock 38acan be designed as a counter that begins timing or counting in response to a start signal transmitted by the vehicle manager 29. Therefore, the vehicle manager 29 transmits the start signal when the vehicle 17 starts the route, and thereafter, the vehicle manager 29 can determine the amount of time that has lapsed since the start of the route by analyzing the value of the clock 38a. Other devices and/or methodologies may be employed to determine the amount of time that has lapsed since the start of the route without departing from the principles of the present invention.

[0046] As the vehicle 17 travels along the predetermined route of travel, the vehicle manager 29 is configured to determine the vehicle's current position by analyzing the location values from the sensor 18. Furthermore, as the vehicle 17 travels, the vehicle 17 passes the points or locations along the route that are defined in the vehicle schedule 39a. The vehicle manager 29 is designed to compare the current location values of the vehicle 17 (i.e., of the sensor 18) with the location values defined by the vehicle schedule 39ain order to determine which entry in the vehicle schedule 39acorresponds with the current location of the vehicle 17. In the preferred embodiment, the entry that corresponds with the current location of the vehicle 17 is the entry having location values most closely matching the location values currently supplied by the sensor 18. In other words, the corresponding entry includes location values representing the location that is closest to the location of the vehicle 17. This entry will be referred to hereinafter as the “corresponding entry.”

[0047] After determining which entry corresponds with the current location of the vehicle 17, the vehicle manager 29 is designed to determine whether the vehicle 17 is off schedule or on schedule. The vehicle 17 is off schedule if the amount of time that has lapsed since the start of the route differs from an estimated lapsed time by a predetermined amount of time. In the preferred embodiment, the estimated lapsed time is represented by the time value in the corresponding entry of the vehicle schedule 39a. As an example, assume for illustrative purposes only that the predetermined amount of time is five minutes. If the vehicle manager 29 determines that the difference between the actual lapsed time since the start of the trip and the estimated lapsed time (i.e., the time value in the corresponding entry) is greater than five minutes, then the vehicle 17 is off schedule. Otherwise the vehicle 17 is on schedule.

[0048] Furthermore, if the vehicle 17 is off schedule, then the vehicle manager 29 is also designed to determine whether the vehicle 17 is early or late. If the actual time lapsed since the start of the trip is greater than the estimated lapsed time, then the vehicle 17 is late. If the actual time lapsed since the start of the trip is less than the estimated lapsed time, then the vehicle 17 is early.

[0049] Alternatively, the vehicle manager 29 can be configured to select the corresponding entry in the predefined schedule 39avia comparison of time values instead of location values. In this regard, the vehicle manager 29 can be configured to compare the current time value indicated by the clock 38a(e.g., the lapsed time since the start of the route) with the time values in the entries of the vehicle schedule 39a. The corresponding entry is then the entry in vehicle schedule 39ahaving the estimated time value that differs the least with the actual time value indicated by clock 38a.

[0050] In this situation, the vehicle manager 29 compares the current location values from sensor 18 with the location values associated with the corresponding entry of the vehicle schedule 39ain order to determine whether or not the vehicle 17 is on schedule. If the location values differ by more than a predefined threshold value, then the vehicle 17 is off schedule. Otherwise, the vehicle is on schedule. Furthermore, if the actual location of the vehicle 17 (as defined by the current location values from sensor 18) is further along the route of travel than the location associated with the corresponding entry (as defined by the location values in the corresponding entry), then the vehicle 17 is early. If the location associated with the corresponding entry (as defined by the location values in the corresponding entry) is further along the route of travel than the actual location of the vehicle 17 (as defined by the current location values from sensor 18), then the vehicle 17 is late.

[0051] In response to a determination by the vehicle manager 29 that the vehicle 17 is off schedule, the vehicle manager 29 is designed to transmit a status message to Base Station Control Unit (BSCU) 40 (FIG. 1), which is remotely located from the vehicle 17. The status message preferably indicates that vehicle 17 is off schedule and indicates the amount that vehicle 17 is off schedule. Co-pending U.S. Patent Application entitled “System and Method for Enciphering and Communicating Vehicle Tracking Information” filed by Jones, et al. on Sep. 30, 1998, and assigned Ser. No. 09/163,606, which is incorporated herein by reference, describes a system and method for transmitting messages to BSCU 40.

[0052] Transmission of a Status Message

[0053] BSCU 40 preferably includes a base station manager 41 designed to monitor the travel of each vehicle 17 associated with the system 10. In the preferred embodiment, unlike the VCU 15, the BSCU 40 is substantially non-mobile. As an example, the BSCU 40 can be located in a central office of a telephone company.

[0054] The base station manager 41 can be implemented in software, hardware, or a combination thereof. In the preferred embodiment, as illustrated by way of example in FIG. 4, the base station manager 41 of the present invention along with its associated methodology is implemented in software and stored in computer memory 30bof a computer system 31b. The computer system 31bcan be similar to computer system 31a, as can be seen by comparing FIG. 3 to FIG. 4. In this regard, the computer system 31bmay include memory 30bfor storing the base station manager 41, and the computer system 31bmay also include processing element 32b, local interface 33b, input 34b, display 35b, printer 36b, and storage disk 37b. It may also be desirable for computer system 31bto include a network interface 42 that allows the system 31bto exchange data with a network 43. It should be noted that input device 34b, display 35b, printer 36b, disk 37b, network interface 42, and network 43 are optional.

[0055] In order to transmit the status message to the BSCU 40, the vehicle manager 29 is configured to transmit the status message, via signal 43 (FIG. 2), to a communications device 44, which is capable of transmitting and receiving data to and from devices outside of vehicle 17. In this regard, communications device 44 is preferably a cellular modem configured to transmit and receive wireless signals to and from a cellular network 48 (FIG. 1).

[0056] The communications device 44 can transmit the status message over the voice channels associated with the cellular network 48, as is done by most cellular modems of the prior art. However, in order to reduce the cost associated with transmitting the travel data through the cellular network 48, the status message may be communicated through the cellular network 48 via a data or control channel. In this regard, the status message can be encoded by altering identifiers of the communications device 44, such as the mobile identification number (MIN) or electronic serial number (ESN), transmitted over a data channel of the cellular network 48. Alternatively, the status message can be appended to a feature request transmitted over the data channel. U.S. Pat. No. 5,771,445 entitled “Data Messaging in a Communications Network using a Feature Request,” filed on Dec. 15, 1995, by Kennedy, III, et al., and U.S. Pat. No. 5,546,444 entitled “Methods and Apparatus for Communicating Data Via a Cellular Network Control Channel” filed on Mar. 11, 1994, by Roach, Jr., et al., which are both incorporated herein by reference, discuss the transmission of travel data over a data or control channel associated with the cellular network 48 in further detail.

[0057] In order to transmit the status message through a data channel by manipulating identifiers of the communications device 44, the MIN of the communications device 44 is altered to include the status message, but the ESN remains fixed to be used as an identifier of the communications device 44. Therefore, after transmitting the identifiers through the data channel, the communications device 44 can be identified by the ESN, and the status message can be determined from the MIN. Alternatively, the ESN of communications device 44 can be altered while the MIN is kept constant. It should be understood that the invention contemplates modification of the MIN, ESN, both the MIN and ESN, or other identifiers of the communications device 44 to accomplish the dual task of transmitting status messages and identifying the communications device 44.

[0058] Alternatively or in combination with the manipulation of the identifiers of the communications device 44, the status message can be communicated through the data channel by appending the status message to feature requests that are transmitted through the data channel. In this regard, most feature requests are generated by automatically or manually dialing the star key (“*”) followed by a two-digit feature request identification code, and 29 digits of data. Therefore, for each feature request generated, 29 digits of data pertaining to the status message can be appended to the two-digit feature request identification code and sent over the data channel of the cellular network 48. Other embodiments may transmit different amounts of data following the feature request. By utilizing the manipulation of identifiers or the appendage of travel data to feature requests, less data is transmitted through the voice channels of the cellular network 48, thereby reducing the cost of transmitting data through the cellular network 48.

[0059] In order for successful communication to exist between vehicle manager 29 and base station manager 41, both managers 29 and 41 should be aware of the communication protocol utilized. Therefore, it is desirable for the base station manager 41 or the vehicle manager 29 to initially transmit an instruction via the data channel of the cellular network 48 to the other manager 29 or 41 indicating the protocol to be utilized. Thereafter, the vehicle manager 29 transmits messages to the base station manager 41 via the selected protocol.

[0060] Cellular network 48 is designed to transmit the status message to a communications device 52 (FIG. 1) at the BSCU 40. Although not necessary for implementation of the present invention, cellular network 48 is preferably designed to transmit to the communications device 52 via a public switched telephone network (PSTN) 55. In this regard, PSTN 55 establishes a link between communications device 52 and cellular network 48, whereby cellular network 48 and communications device 52 can communicate via signals 61 and 65, which are transmitted over land-line connections in the preferred embodiment. Therefore, communications device 52 is preferably designed as a PSTN modem capable of communicating signals 65 between base station manager 41 and PSTN network 55.

[0061] Although the preferred embodiment utilizes a cellular network 48 and a PSTN network 55 to communicate travel data to base station manager 41, one ordinarily skilled in the art should realize that other configurations are possible. For example, communications device 52 can be configured as a cellular modem capable of communicating signals directly with cellular network 48. Alternatively, utilization of communication networks 48 and 55 can be completely circumvented by configuring the communications device 44 to communicate directly with communications device 52, for example. Any embodiment capable of communicating data between vehicle manager 29 and base station manager 41 should be suitable for implementing the principles of the present invention.

[0062] It should be noted that by transmitting a status message only when the vehicle 17 is off schedule reduces the cost of operating the system 10. In this regard, communication through a cellular network 48 is relatively expensive, and the cost is based on the amount of data transmitted. By refraining from transmitting any data from the vehicle manager 29 to the base station manager 41 when the vehicle 17 is on schedule, the amount of data transmitted through the cellular network 48 is reduced, thereby reducing the communication cost associated with the system 10. Therefore, the present invention's methodology of assuming the vehicle 17 is on schedule and of only transmitting data to the base station manager 41 when the vehicle 17 is off schedule enables the system 10 to minimize costs.

[0063] Base Station Manager

[0064] Base station manager 41 is designed to monitor the travel of the vehicle 17 and (when employed in the context of advance notification system 12) is also designed to transmit a notification message to a user when the vehicle 17 is a predetermined proximity from a particular vehicle destination or other location. The predetermined proximity can be a particular time or distance that the vehicle 17 is from the destination. If the vehicle 17 is off schedule, then the base station manager 41 is further configured to transmit a message to the user indicating that the vehicle 17 is off schedule.

[0065] The base station manager 41 of tracking system 10 is designed to determine the current location of the vehicle 17 and to compare the current location of the vehicle 17 to a predefined location along the route of travel of the vehicle 17 in order to determine whether notification should be sent to the user. In this regard, like the vehicle manager 29, the base station manager 41 includes a predefined schedule 39b, referred herein as the “base station schedule 39b,” in memory 30b. Furthermore, similar to the computer system 31a(FIG. 3), the computer system 31b(FIG. 4) includes a clock 39bor other type of counter that can be used to determine the amount of time that has lapsed since the vehicle 17 started traveling along the vehicle's route. When the vehicle 17 begins the route, the vehicle manager 29 preferably transmits a message to the base station manager 41 via communication devices 44 and 52 indicating that travel on the route is beginning. In response, the base station manager 41, like the vehicle manager 29, begins monitoring the amount of time lapsed since the start of the route.

[0066] In the preferred embodiment, the base station schedule 39bstored in memory 30bmatches the vehicle schedule 39astored in memory 30a, although variations in the two predefined schedules 39aand 39bare possible. Furthermore, the base station manager 41 is configured to retrieve an entry, the “corresponding entry,” in the base station schedule 39bcorresponding with the amount of time lapsed since the vehicle 17 began travelling its route. In this regard, the base station manager 41 compares the amount of time that has lapsed since the vehicle 17 began its route (as determined from the clock 38bat the BSCU 40) with the time values in the base station schedule 39b. The corresponding entry in the base station schedule 39bis the entry having the time value differing the least with the value indicated by the clock 38b(i.e., the time value indicating the amount of time that has lapsed since the vehicle 17 began its route).

[0067] The base station manager 41 assumes that the vehicle 17 is on schedule, unless the base station manager 41 has received a recent status message from the vehicle manager 29. As used herein, a “recent status message” is the most recent status message that has been received by the base station manager 41 within a predetermined time. For example, a recent status message could be the latest status message received within the last five minutes or some other suitable time frame. Therefore, if the base station manager 41 has not received a recent status message from the vehicle manager 29, then the base station manager 41 assumes that the location values in the corresponding entry of the predefined base station schedule 39bindicate the current location of the vehicle 17.

[0068] Recalling that base station manager 41 (when employed within the context of notification system 12) is to transmit a notification message when the vehicle 17 is a predetermined proximity from a particular location (e.g., a vehicle stop), the base station manager 41 then compares the location values in the corresponding entry (which represent the current location of the vehicle 17) with location values defining the predetermined proximity. If the location values from the corresponding entry differ from the location values of the predetermined proximity by less than a predetermined amount, then the base station manager 41 transmits a notification message to the user. Otherwise no notification message is transmitted to the user.

[0069] Alternatively, the base station manager 41 can be configured to compare time values instead of location values in order to determine whether a notification message should be transmitted to the user. In this regard, the base station manager 41 is designed to compare the time value in the corresponding entry with a predetermined threshold value indicating the amount of time that should lapse between the vehicle 17 starting its route and arriving at a location associated with the predetermined proximity (e.g., a threshold value indicating how long the vehicle should travel along its route before notification should be sent to the user). If the threshold value in the corresponding entry exceeds the predetermined time value, then the base station 41 transmits a notification message to the user.

[0070] If the base station manager 41 of tracking system 10 has received a recent status message from the vehicle manager 29, then the base station manager 41 determines the actual location values of the vehicle 17 based on the location values in the corresponding entry and the recent status message. In this regard, the location values in the corresponding entry represent the estimated location of the vehicle 17. The status message indicates how much the vehicle 17 is off schedule (i.e., how far the vehicle 17 is from the estimated location). For example, the status message can indicate that the vehicle is five miles off schedule. Therefore, the base station manager 41 is designed to calculate new location values based on the estimated location and the status message. These new location values represent the actual location of the vehicle 17. Therefore, by using the new location values instead of the values in the corresponding entry, the base station manager 41 can determine whether a notification message should be sent to the user according to the methodology described hereinabove.

[0071] Furthermore, instead of indicating how far the vehicle is from the estimated location via location values, the status message can indicate how far the vehicle 17 is from the estimated location via a time value (e.g., the status message can indicate that the vehicle 17 is ten minutes late). In this case, the base station manager 41 is designed to adjust the time value in the corresponding entry to account for the vehicle 17 being off schedule. For example, if the vehicle 17 is early, then the time value in the corresponding entry is increased a corresponding amount, and if the vehicle 17 is late, then the time value in the corresponding entry is decreased a corresponding amount. This adjusted time value is then compared with the predetermined threshold value described hereinabove in order to determine whether notification should be sent. If the adjusted time exceeds the predetermined time value, then the base station 41 transmits a notification message to the user.

[0072] In an alternative embodiment, the location values transmitted in the status message can represent the actual location of the vehicle 17 instead of representing how far the vehicle 17 is off schedule. In this embodiment, the base station manager 41 can be designed to directly compare these location values with the location values defining the predetermined proximity in order to determine whether notification should be sent to the user. Accordingly, if these location values differ from the location values defining the predetermined proximity by less than a predetermined amount, then the base station manager 41 transmits a notification message to the user. Otherwise, no notification message is sent to the user.

[0073] Furthermore, when the base station manager 41 determines that the vehicle 17 is off schedule, the base station manager preferably transmits an off schedule message to the user, as described hereinbelow, to notify the user that the vehicle 17 is off schedule. This message can include a variety of information including, but not limited, how much (in time or distance) the vehicle 17 is off schedule. However, it should be noted that communication of the off schedule message is not a necessary feature of the present invention.

[0074] Transmission of Off Schedule and Notification Messages

[0075] Once the base station manager 41 of systems 10 and 12 determines that a notification or an off schedule message should be sent to a user, the base station manager 41 is designed to communicate the message to the user via PSTN network 55 and communications devices 72 and 73 (FIG. 1). In this regard, communications devices 72 and 73 are preferably PSTN modems capable of interfacing with and communicating with PSTN network 55. Base station manager 41 is designed to transmit the message as signal 70 to user communications device 72, which communicates the message with PTSN network 55 via signal 74. PTSN network 55 then communicates the message to communications device 73, which is preferably configured to communicate the message to a message device 75. Message device 75 is configured to notify the user of the message. Preferably, message device 75 is a computer capable of displaying the notification through e-mail or some other communications software. Alternatively, message device 75 can be a telephone, a pager or any other device capable of notifying the user. Furthermore, a plurality of communications devices 72 preferably exist so that the base station manager 41 can simultaneously notify a plurality of users or parties of the impending arrival of the vehicle 17 at the vehicle stop.

[0076] Although the preferred embodiment utilizes a PSTN network 55 to communicate a notification or an off schedule message to message device 75, one ordinarily skilled in the art should realize that other configurations are possible. For example, other communication networks can be utilized or utilization of communication networks can be completely circumvented by configuring communications device 72 to communicate directly with communications device 73. Any embodiment capable of communicating data between base station manager 41 and message device 75 should be suitable for implementing the principles of the present invention.

[0077] As an example, the base station manager 41 may notify the user of the impending arrival of the vehicle 17 by transmitting a distinctive ring to the user's message device. In this embodiment, the message device 75 is a telephone ringer. A distinctive ring is a ringing cadence that is different than the standard ringing cadence used to notify the user of a telephone call. Since the user can different the different ringing cadence, the user is aware that the telephone call corresponds to a notification message from the base station manager 41 indicating that arrival of the vehicle 17 is imminent. A system for transmitting a distinctive telephone ring as the notification message is fully described in U.S. Patent Application entitled “Advance Notification System and Method Utilizing a Distinctive Telephone Ring,” assigned Ser. No. 08/762,052 and filed on Dec. 9, 1996, which is incorporated herein by reference.

[0078] Creation of the Vehicle and Base Station Schedules

[0079] It should be noted that the predefined vehicle schedule 39aand the predefined base station schedule 39bcan be determined or defined by a variety of methodologies. For example, the predetermined schedules 39aand 39bcan be estimated based on various factors, such as the types of speeds likely to be traveled by the vehicle 17 and the types of traffic conditions expected to be encountered during travel. However, in the preferred embodiment, the predefined schedules 39aand 39bare defined via a previous delivery of the vehicle 17 along the same route of travel.

[0080] In this regard, delivery vehicles 17 frequently travel the same routes. This is especially true for buses, for example, where a bus routinely travels the same route and makes the same stops. As the vehicle 17 is traveling the route, the vehicle manager 29 is configured to periodically read the sensor 18 and to store an entry in memory 30a. The entry preferably includes the current location values of the vehicle 17 indicated by sensor 18 and the time value indicated by clock 38a(i.e., the time value indicating the amount of time that has lapsed since the start of the travel on the route). Therefore, when the vehicle 17 reaches the end of the route, the vehicle manager 29 has stored numerous entries which define the predefined vehicle schedule 39a. This predefined schedule 39amay also be used as the base station schedule 39b. Other methodologies may be employed to define the vehicle schedule 39aand/or the base station schedule 39b.

[0081] FIG. 5 is a flow chart depicting the operation and functionality of the vehicle manager 29 in embodiments where the vehicle manager 29 determines the vehicle schedule 39awhile traveling along the route of travel. As shown by blocks 76 and 77, the vehicle manager 29 determines whether a sample period has expired while the vehicle is traveling on the route (i.e., before the vehicle 17 has finished the route). The sample period is a predetermined amount of time that lapses between samples, which will be discussed in more detail hereinbelow. Preferably, the vehicle clock 38aindicates whether the sample period has expired. For example, when the clock 38ais a counter, the sample period can be defined as a predetermined number of counts by the clock 38a. Therefore, the vehicle manger 29 can determine whether the sample period has expired by counting the number of increments or cycles of the clock 38a.

[0082] When the vehicle manager 29 determines that the sample period has expired, the vehicle manager 29 samples the current location values of the vehicle 17 and the time value of the clock 38a. In other words, the vehicle manager 29 determines the current location values of the vehicle 17 and the current time value from the clock 38aand stores these values in the next entry of the vehicle schedule 39a, as depicted by blocks 78 and 79. This process repeats until the vehicle manager 29 determines that the vehicle 17 has completed the route. Thereafter, the vehicle manager 29 can use the vehicle schedule 39ato track the vehicle's progress on future deliveries that utilize the route defined by the vehicle schedule 39a.

[0083] Alarm System

[0084] Preferably, the vehicle manager 29 is further configured to compare the corresponding entry and the location values supplied from the sensor 18 in order to determine whether an alarm signal should be generated. In this regard, the vehicle manager 29 preferably subtracts the location values in the corresponding entry from the current location values of the vehicle 17 (as determined by the sensor 18) to produce a deviation indicator. Therefore, the deviation indicator indicates how far the vehicle 17 has deviated from the route defined by the vehicle schedule 39a.

[0085] The vehicle manager 29 is then designed to compare the deviation indictor to an alarm threshold value to determine whether an alarm signal should be transmitted to the base station manager 41. The alarm threshold value corresponds with the distance that the vehicle 17 can deviate from the predefined vehicle schedule 39abefore an alarm is generated. Therefore, if the deviation indicator exceeds the alarm threshold value, the vehicle manager 29 transmits an alarm message to the base station manager 41 via communications devices 44 and 52. Preferably the alarm message includes the current location values produced by the sensor 18 so that the travel of the vehicle 17 can be tracked by the base station manager 41.

[0086] Providing an alarm message, as described hereinabove, helps to discover when a vehicle 17 has been stolen or hijacked and helps law enforcement agencies to recover the vehicle 17 by tracking the travel of the vehicle 17 once the vehicle 17 has been stolen. In this regard, the vehicle manager 29 automatically generates an alarm message and monitors travel of the vehicle 17 once the vehicle 17 deviates from the vehicle schedule 39aby a predetermined amount. The alarm message can be used by law enforcement agencies to discover when the vehicle 17 has been stolen and where the vehicle 17 is located, thereby helping law enforcement agencies to recover the vehicle 17 once it has been stolen.

[0087] Because the deviation indicator is defined relative to points along the vehicle's route of travel, an alarm can be generated when the vehicle 17 deviates from the route by a relatively small amount. For example, the vehicle manager 29 can be configured to transmit an alarm signal when the vehicle 17 deviates from its predefined route by approximately 20 feet. Other distances, both less than and greater than 20 feet, may be used to trigger an alarm signal. However, it is generally desirable that a certain amount of deviation (depending on the expected driving conditions and the precision of sensor 18) be allowed so that the vehicle 17 can reasonably maneuver through traffic without generating false alarms.

[0088] In addition, the alarm threshold value is selectable in the preferred embodiment. This value can be entered into the computer system 31aby a human operator at the vehicle 17 via input device 34a, for example. Alternatively, this value can be communicated from the base station manager 41 to the vehicle manager 29 via communications devices 44 and 52 at or around the start of the route. The alarm threshold value can also be hardwired into the computer system 31awith switches that can be manipulated by a human operator in order to selectively change the value. Many other methodologies known in the art may be used for selecting the value of the alarm threshold value.

[0089] It should be noted that in other embodiments, it may be desirable for the vehicle manager 29 to generate an alarm signal based on comparisons of the location of vehicle 17 to a predefined geographical region instead of the route defined in vehicle schedule 39a. For example, it may desirable to define a region that is 30 miles (or some other distance) from the start of the route (or some other particular location). Then, the vehicle manager 29 can be configured to generate an alarm signal if the vehicle manager 29 determines that the vehicle 17 is outside of this predefined region based on the signals 27 received from sensor 18. Such a methodology for generating an alarm signal is particularly suitable for applications where only local deliveries are expected, for example.

[0090] There are various methodologies for determining whether the vehicle 17 is outside of the predefined region. For example, in one embodiment, the vehicle manger 29 subtracts the current location values determined from signals 27 with the location values of a particular point (e.g., the location values of the start of the route, when the region is defined as any point within a certain distance of the start of the route) to derive the deviation indicator. As in the preferred embodiment, if the deviation indicator has a magnitude greater than the alarm threshold value, the vehicle manager 29 generates an alarm signal. Otherwise, no alarm signal is generated.

[0091] Providing Base Station Services

[0092] It should be noted that a single BSCU 40 may be used to service a plurality of VCUs 15. Therefore, it may be desirable for a telephone company (or other entity) to provide the services of the BSCU 40 and to allow many different customers to subscribe for the services of the BSCU 40. In this regard, each customer can acquire a VCU 15 and can contact the telephone company (or other entity providing the services of the BSCU 40) to request the services of the BSCU 40. In exchange for the payment of a subscription fee, the services of the BSCU 40 can be provided to the customer. When the entity providing the services of the BSCU 40 is a telephone company, the telephone company can include the bill of the subscription fee in the customer's telephone bill. For example, a customer usually receives a telephone bill from the telephone company in exchange for the capability of utilizing the PSTN 55 or other networks. The subscription fee for providing the services of the BSCU 10 can be included in this telephone bill.

[0093] After establishing the subscription, the customer is preferably allowed to establish when he or she would like to be notified of an impending arrival of a vehicle 17. For example, the customer may be allowed to establish communication with the base station manager 41 (either directly via a telephone call and touch tone signaling, for example, or indirectly via an operator interfaced with the base station manager 41) and to identify the vehicle 17 or VCU 15 to be monitored and the predetermined location that should be used to determine when a notification message is transmitted to the customer. Alternatively, the customer may be allowed to provide a time period or distance that the identified vehicle 17 or VCU 15 should be from a particular location (e.g., a scheduled vehicle stop) before a notification message is transmitted. In response, the base station manager 41 is designed to determine the location values of the predetermined location (if the location values are not already provided by the customer) and to store the location values in memory 30b(FIG. 4). Then, the services of the BSCU 40 may be provided to the customer via the techniques described herein.

[0094] In addition, the customer may be allowed to obtain a status report as a service of the BSCU 40. In this regard, the customer may be allowed to establish communication with the base station manager 41 either directly or indirectly and to request a status report for a particular vehicle 17. In response, the base station manager 41 is designed to determine the current location of the vehicle 17 according to the techniques described hereinabove and to transmit information (e.g., the location of the vehicle 17, the distance the vehicle 17 is from a particular location, or the time the vehicle 17 is from a particular location etc.) indicating the proximity of the vehicle 17. A system allowing a customer to establish the parameters used by the base station manager 41 to monitor the vehicle 17 and to request status reports is fully described in U.S. Patent Application entitled “System and Method for Activation of an Advance Notification System for Monitoring and Reporting Status of Vehicle Travel,” assigned Ser. No. 09/163,588 and filed on Sep. 30, 1998, which is incorporated herein by reference.

[0095] In a second embodiment of the present invention, the “corresponding entry” of the vehicle schedule 39ais defined as the entry having location values defining a location along the route that was most recently passed by the vehicle 17. Therefore, the vehicle manager 29 monitors the signals 27 from the sensor 18 until the vehicle manager 29 determines that the vehicle passed a location corresponding with one of the entries in the vehicle schedule 39a. The vehicle manager 29 determines whether the vehicle 17 is early or late via the techniques described hereinabove using the aforementioned entry as the corresponding entry.

[0096] After determining whether to generate an alarm signal and/or status message for the corresponding entry (and after generating the alarm signal and/or the status message, if necessary), the vehicle manager 29 monitors the signals 27 again for the next corresponding entry. Therefore, when a corresponding entry is detected (i.e., when the vehicle manager 29 determines that the vehicle 17 passed a location corresponding with the location values in one of the entries of the vehicle schedule 39afor the first time), the vehicle manager 29 analyzes the values of the sensor 18, the clock 38a, and the corresponding entry to determine whether an alarm signal and/or status message should be generated. Thereafter, the vehicle manager 29 waits until the next corresponding entry is detected before determining whether to generate another status message. Therefore, the vehicle manager 29 determines whether a status message should be communicated to the base station manager 41 each time the vehicle 17 passes a location corresponding with the location values in one of the entries of the vehicle schedule 39a, and the vehicle manager 29 refrains from communicating status messages as the vehicle 17 travels between locations defined by the data in the vehicle schedule 39a. In other words, the only time the vehicle manager 28 transmits a status message is when the vehicle 17 is passing a location corresponding with one of the entries in the vehicle schedule 39aor a short time thereafter.

[0097] However, since it is possible for the vehicle 17 not to pass any of the locations defined in the predefined schedule when the vehicle deviates from the route (e.g., when the vehicle 17 is stolen), the vehicle manager 29 preferably determines whether to communicate an alarm signal periodically rather than waiting for one of the locations defined by the vehicle manager 29 to be passed.

[0098] The preferred use and operation of the system 10 and associated methodology are described hereafter. For illustrative purposes only, assume that the vehicle 17 is to travel a predetermined route to a destination where the vehicle 17 is to pick up or deliver an item. For example, assume that the vehicle 17 is a bus that is to travel to a bus stop to pick up a passenger and that this passenger is to receive a notification signal when the vehicle 17 is ten minutes from the bus stop.

[0099] Initially, the vehicle schedule 39ais stored in the vehicle manager 29 and the base station schedule 39ais stored in the base station manager 41. In the preferred embodiment, the vehicle schedule 39awas created and stored in the vehicle manager 29 as the vehicle 17 previously traveled along the same route. A copy of the vehicle schedule 39ais preferably transferred to the base station manager 41 via any suitable methodology and stored as the base station schedule 39a. For example, the vehicle schedule 39acan be copied to a magnetic disk and later downloaded in memory 30bor a copy of the vehicle schedule 39acan be transmitted to the base station manager 41 via communications devices 44 and 52.

[0100] In embodiments where the vehicle schedule 39ais not previously created and stored by the vehicle manager 29, the vehicle schedule 39ais preferably downloaded into both the base station manager 41 and the vehicle manager 29. It is possible to download the base station schedule 39ain the base station manager 41 and to transmit a copy of the base station schedule 39ato the vehicle manager 29 via communications devices 44 and 52 prior to the start of the route. Any methodology for respectively storing the vehicle schedule 39aand the base station schedule 39binto the vehicle manager 29 and the base station manager 41 is suitable for the purposes of the present invention.

[0101] When the vehicle 17 begins travel, the vehicle manager 29 stores the current value of the vehicle clock 38aand begins to monitor the amount of time that lapses from that point until completion of the route. Furthermore, as can be seen by block 82 of FIG. 6, the vehicle manager 29 also transmits a start signal to the base station manger 41 via communications devices 44 and 52 indicating that travel of the vehicle 17 is beginning. In response, the base station manager 41 begins to monitor the lapsed time as well.

[0102] In many situations, it may be desirable to begin monitoring travel of the vehicle 17 after the vehicle 17 starts its route. This is particularly true when unpredictable delays usually occur close to the staring point of the route. For example, when the vehicle 17 is a school bus taking children home from school, unpredictable delays may occur close to the starting point (i.e., at the school) where traffic is often congested. Therefore, instead of transmitting a start signal to the base station manager 41 when the vehicle 17 begins traveling, the vehicle manager 29 waits for a predetermined time period or until the vehicle 17 has traveled a predetermined distance from the starting point before transmitting the start signal. For example, the vehicle manager 29 can monitor the travel of the vehicle 17 from the starting point via the sensor 18 and transmit the start signal once the vehicle manager 29 determines that the vehicle has traveled one-eighth of a mile from the starting point. In this regard, location values representing a predetermined point along the route of travel and one-eighth of a mile from the starting point can be stored in the vehicle manager 29. When the vehicle manager 29 determines that the vehicle 17 passes this point, the vehicle manager 29 determines that the vehicle 29 has traveled more than one-eighth of a mile and transmits the start signal.

[0103] Preferably, the predetermined schedules 39aand 39bboth use the point where the vehicle manager 29 transmits the start signal as the starting point for the route. Therefore, the distances and times stored in the predetermined schedules 39aand 39bare relative to the predetermined location where vehicle manager 29 transmits the start signal instead of the actual starting point of the route. However, this is not a necessary feature of the present invention, and the location values and time values stored in the predetermined schedules 39aand 39bmay be relative to other points both along the route of travel and outside of the route of travel.

[0104] As the vehicle 17 travels, GPS satellites 23 transmit wireless signals 21a-21cto sensor 18 that can be analyzed through techniques well known in the art to determine a position (i.e., current location values) of the sensor 18 (and, therefore, of the vehicle 17) relative to a particular reference point, as depicted by block 85 of FIG. 6. For example, in GPS systems, the intersection of the Equator and the Prime Meridian is typically used as the reference point. Sensor 18 receives the signals 21a-21cand determines location values representing the position of the vehicle 17 relative to the reference point and transmits these values to vehicle manager 29.

[0105] The vehicle manager 29 compares the current location values of the vehicle 17 with the location values in the vehicle schedule 39ain order to determine which entry in the vehicle schedule 39acorresponds with the current location of the vehicle 17, as shown by block 87 of FIG. 6. The corresponding entry is preferably the entry having location values that most closely match the current location values received from the sensor 18.

[0106] After selecting the corresponding entry, the vehicle manager 29 retrieves the location values associated with the corresponding entry and subtracts these values from the current location values received from the sensor 18 and used by the vehicle manager 29 to select the corresponding entry. Referring to block 91 of FIG. 6, the resulting value or values (referred to as the deviation indicator) indicates the vehicle's deviation from the vehicle schedule 39a. As shown by block 93 of FIG. 6, the vehicle manager 29 then compares the deviation indicator to the alarm threshold value. If the deviation indicator exceeds the alarm threshold value, then the vehicle manager 29 transmits an alarm message to the base station manager 41, as depicted by block 95 of FIG. 6. The alarm message includes the current location of the vehicle 18, and the base station manager 41 tracks the location of the vehicle 17 based on the alarm messages transmitted from the vehicle manager 29. The information provided by the alarm message can be used by law enforcement agencies to track the vehicle 18.

[0107] After determining whether an alarm message should be generated, the vehicle manager 29 retrieves the time value associated with the corresponding entry and compares it with the time value indicated by clock 38a(i.e., the time value indicating the amount of time elapsed since the start of the route). The vehicle manager 29 also retrieves a predetermined threshold value indicating how much the vehicle 17 can deviate from the vehicle predefined schedule 39abefore the vehicle 17 is considered to be off schedule. Referring to block 97 of FIG. 6, if the difference of the foregoing time values exceeds the predetermined threshold value, then the vehicle manager 29 determines that the vehicle 17 is off schedule. However, if the difference of the foregoing time values is less than the predetermined threshold value, then the vehicle manager 29 determines that the vehicle 17 is on schedule.

[0108] When the vehicle manager 29 determines that the vehicle 17 is on schedule, the vehicle manager takes no further action regarding the current location values received from the sensor 18. The vehicle manager 29 merely receives a new set of location values from the sensor 18 and analyzes the new set of values according to the methodology described herein. However, when the vehicle manager 29 determines that the vehicle 17 is off schedule, the vehicle manager 29 generates a status message and transmits the status message to the base station manager 41, as depicted by block 99 of FIG. 6.

[0109] In this regard, the vehicle manager 29 determines whether the vehicle 17 is early or late and how far the vehicle 17 is off schedule (e.g., how many minutes or miles the vehicle 17 is from the location specified by the location values in the corresponding entry). The vehicle manager 29 then generates a status message including this information and transmits the status message to the base station manager 41 via communications devices 44 and 52.

[0110] In order to reduce the number of transmissions between the vehicle 17 and the base station control unit 40, the vehicle manager 29 preferably transmits the status message to the base station manager 41 only if another status message has not been transmitted within a predetermined delay period. For example, if a status message has been sent within the last five minutes, then the vehicle manager 29 refrains from sending another status message. It should be apparent to one skilled in the art that other delay periods can be selected to update the location of the vehicle 17 at a desirable rate.

[0111] Furthermore, it is possible to selectively control the delay period. For example, when the vehicle 17 stops to make a delivery or is slowly traveling through congested areas, it may be desirable to increase the delay period to decrease the number of status messages sent to the base station manager 41. Alternatively, when the vehicle 17 is traveling quickly and the location of the vehicle 17 is changing rapidly, it may be desirable to decrease the delay period. Furthermore, when the vehicle 17 enters an area where no immediate deliveries or pick ups are to made, there is no immediate need to monitor the vehicle 17 and the delay period can be increased. The delay periods can be predefined in memory 30a, can be controlled by the operator of the vehicle 17, or can be controlled via signals transmitted from remote locations to the vehicle manager 29 (e.g., from the base station manager 41 to the vehicle manager 29 via communications device 44). Other methodologies for controlling the delay periods are possible.

[0112] Another way to reduce the number of transmissions of status messages at desired times is to selectively increase the predefined amount that the vehicle 17 should be off schedule before a status message is transmitted to the base station control manager 41. Similar to the changes in the delay periods described above, the changes to the aforementioned predefined amount can be predefined in memory 30a, can be controlled by the operator of the vehicle 17, or can be controlled via signals transmitted from remote locations to the vehicle manager 29 (e.g., from base station manager 41 to vehicle manager 29 via communications device 44).

[0113] The input device 34a(FIG. 3) can be used to input changes in the delay period and/or in the predefined amount that the vehicle should be off schedule before a status message is transmitted. In this regard, the input device 34 a may include switches, buttons, a key pad, or any other device that can be manipulated by the operator of the vehicle 17 to input the changes.

[0114] When the base station manager 41 receives a status message, the base station manager 41 stores the status message in memory 30b. If desired, the base station manager 41 transmits a message to the user via communications devices 72 and 73 indicating that the vehicle 17 is off schedule and indicating how much the vehicle 17 is off schedule in response to the status message.

[0115] The base station manager 41 periodically determines whether a notification message should be sent to the user indicating that arrival of the vehicle 17 at the bus stop is imminent (e.g., indicating that the vehicle 17 is ten minutes from the bus stop). In this regard, the notification message should be sent to the user when the vehicle 17 is within a predetermined proximity (i.e., a predetermined time or distance) from the bus stop. To determine whether the notification message should be sent, the base station manager 41 compares the location values of the current location of the vehicle 17 to the location values of the predetermined location (e.g., the bus stop). If the difference between the location values of the current location of the vehicle 17 and the bus stop is greater than a threshold value, then the vehicle 17 is too far from the bus stop for notification to be sent to the user. Therefore, a notification message is not generated. However, if the difference between the location values of the current location of the vehicle 17 and the bus stop is less than the threshold value, then a notification message is transmitted to the user via communications devices 72 and 73, unless a similar notification message (i.e., a message indicating that the vehicle 17 is off schedule by the same amount) associated with the bus stop has previously been sent to the user.

[0116] In determining the current location of the vehicle 17, the base station manager 41 assumes that the vehicle 17 is on schedule unless a recent status message has been received. Therefore, the vehicle manager 41 determines which entry in the base station schedule 39bcorresponds to the assumed location of the vehicle 17. In this regard, the vehicle manager 41 compares the time values in the base station schedule 39bwith a lapsed time value indicating how much time has lapsed since the vehicle 17 started the route. The entry having a time value closest to this lapsed time value is the corresponding entry. The location values associated with the corresponding entry represent the assumed location of the vehicle 17. Unless a recent status message has been received, the base station manager 41 uses these location values as the current location values to be compared against the location values of the predetermined location (e.g., the bus stop) in order to determine whether a notification message should be sent to the user. However, if a recent status message has been received, then the base station manager 41 determines the current location values of the vehicle 17 based on the recent status message and/or the location values associated with the corresponding entry.

[0117] For example, if the recent status message includes location values indicating the actual location of the vehicle 17, then the base station manager 41 uses these values to compare with the coordinate values of the predetermined location (e.g., the bus stop). However, if the status message only indicates how much the vehicle 17 is off schedule, then the base station manager 41 calculates the current location values of the vehicle 17 based on the status message and the location values associated with the corresponding entry in the base station schedule 39b.

[0118] Once the current location values of the vehicle 17 have been determined, the base station manager 41 compares the current location values of the vehicle 17 with the location values of the predetermined location (e.g., the bus stop) as previously described hereinabove to determine whether a notification signal should be transmitted to the user.

[0119] The operation of the preferred embodiment of the present invention has been described hereinabove in the context where the vehicle manager 29 compares location values to determine the corresponding entry in the vehicle predefined schedule 39a. Therefore, the vehicle manager 29 compares the time value associated with the corresponding entry in the vehicle schedule 39ato determine whether or not the vehicle 17 is on schedule. However, it should be apparent to one skilled in the art upon reading this disclosure that time values may be compared by the vehicle manager 29 to determine the corresponding entry in the vehicle predefined schedule 39a.

[0120] In this regard, the entry in the vehicle schedule 39ahaving a time value most closely matching the lapsed time value indicated by the clock 38a(i.e., the value indicating the amount of time lapsed since the start of the route) can be selected as the corresponding entry. As a result, the vehicle manager 29 determines how far the vehicle 17 is off schedule based on distance rather than time. For example, if the difference between the current location values of the vehicle 17 (as determined by the sensor 18) and the location values associated with the corresponding entry is greater than a predetermined threshold value, then the vehicle 17 is off schedule. Otherwise, the vehicle 17 is on schedule. Furthermore, regardless of which embodiment is used to determine how far the vehicle 17 is off schedule, the vehicle manager 29 can indicate how far the vehicle 17 is off schedule via the status message using either distance values, time values, or any other type of values known in the art for indicating the position of the vehicle 17.

[0121] It should be noted that the preferred embodiment of the present invention has been described hereinabove assuming that the sensor 18 is capable of determining the vehicle's location based on signals received from satellites 23. However, this is not a necessary feature of the present invention, and any type of sensor 18 that may be used for determining the vehicle's position along the route of travel is sufficient for the purposes of the present invention. For example, the sensor 18 may be designed as an odometer that indicates how far the vehicle 17 travels. Therefore, the predetermined points along the route of travel used to determine whether the vehicle 17 is on or off schedule can be defined in the schedules 39aand 39brelative to their distance from the starting point of the route. In other words, the location values stored in the schedules 39aand 39bcorrespond to distance values indicating how far the predetermined points are from the starting point of the route. Therefore, the vehicle manager 29 can determine how far the vehicle 29 is from any of the predetermined points by determining how far the vehicle 17 has traveled from the starting point of the route.

[0122] In concluding the detailed description, it should be noted that the terminology “preferred embodiment” herein means the one embodiment currently believed by the inventor(s) to be the best embodiment of a plurality of possible embodiments. Moreover, it will be obvious to those skilled in the art that many variations and modifications may be made to the preferred embodiment(s) without substantially departing from the principles of the present invention. All such variations and modifications are intended to be included herein within the teachings of the present invention in this document and to be protected by the scope of the following claims.