Aerial chemical application and control method

[0001] This application is a continuation of U.S. application Ser. No. 10/397,040 filed on Mar. 25, 2003 and issuing as U.S. Pat. No. 6,799,740 for “Chemical Application and Flight Guidance Control System and Method”, which claims priority to Provisional Application No. 60/367,440 filed on Mar. 25, 2002 for “Mosquito Control Guidance System and Method” the disclosures of which are herein incorporated by reference in their entireties, all commonly owned with the present invention.

[0002] This invention generally relates to aerial spraying of chemicals including insecticides, fertilizers and the like, and more particularly to guidance of such aerial spraying for more accurate, safe, and cost effective applications

[0003] The need for safe application of pesticides is well known by these skilled in the art aware of the specific dangers and requirements for meeting established government standards, as well as the educated public aware of health hazards associated with chemicals use to control pests in our environment. By way of example, government statutes are created to regulate the distribution, sale, and use of pesticides to protect people and the environment from adverse effects. Research and technology continually effects and enhances methods and procedures including the control of pest and vector mosquitoes. The use of global positioning satellites improved aerial application of pesticides with research on droplet spectrums and the ability to predict the ultimate fate of these droplets released has emphasized the need and importance of meteorology and real-time application optimization.

[0004] Ground weather and tracking of vehicles is well known as illustrated by way of example with the disclosure of U.S. Pat. No. 6,424,295 for a GPS weather data recording system for use with the applications of chemicals to agricultural fields. Here, a GPS weather data recording system is used to determine a series of positions of a ground vehicle and the velocity of the vehicle as it traverses an agricultural field. The series of positions and velocity trace the ground track across the field while a wind sensor is used to measure wind velocity with respect to the vehicle. As described, during crop dusting, the dispensing vehicle usually a tractor, makes numerous sequential, adjacent passes, dispensing chemicals in a swath across the field in each pass. The tractors driver carefully follows a ground track which ensures that each successive swath over the field is correctly spaced, distance wise, from the previous swath in order to avoid gaps or overlaps in coverage. Should one swath occur too close to a previous swath, the overlap area receives excessive amounts of chemicals that may prove very expensive to the farmer and can damage or render crops unusable. As indicated, wind conditions at the commencement of the dispensing operations can be very different from wind conditions half way through or near the end of dispensing operations and as a result it is important that such conditions be properly monitored for accurately tracking these conditions with respect to the ground vehicle position. It can be appreciated that such problems existing for the ground vehicle are very much magnified when attempting to dispense such chemicals from an aircraft. As illustrated by way further example and with reference to U.S. Pat. No. 5,334,987 for an agricultural aircraft control system using a global positioning system, chemicals are applied to an agricultural field in a variety of flight patterns. An aircraft computer stores surface coordinates of the field to be sprayed. Based on stored information, the computer produces a flight pattern having the desired orientation and generates signals representative of the amount and direction of deviation from a desired flight pattern. Such prescription styled farming control systems are used with various navigational controllers as illustrated with reference to U.S. Pat. No. 6,266,595 for a method and apparatus for prescription application of products to an agricultural field.

[0005] In spite of known uses of GPS vehicle location systems, chemical prescription application methods, and monitoring of local weather conditions, there remains a need to safely apply such chemicals in an efficient and cost effective manner. The present invention satisfies this need.

[0006] In view of the foregoing background, an invention including a system and method for controlling a prescribed application of chemicals from an aircraft is herein described. The system may include a first weather station positioned at a preselected altitude and a second weather station positioned generally at ground level. A central communications station may communicate altitude and ground weather data with the first and second weather stations and provides weather information to an aircraft for an appropriate distribution of chemicals based on real-time weather conditions at ground level and at the aircraft altitude. An aerostat may be operable with the first weather station for poisoning it at the preselected altitude. Further, a winch may be mounted at ground level and operable with a tether attached to the aerostat, preferably a gas filled balloon, for controlling the altitude of the balloon.

[0007] The first and second weather stations may comprise instruments that include a magnetometer configured as a directional compass, an anemometer for determining wind speed, a solid state temperature sensor, a solid state sensor for measuring relative humidity, a solid state aneroid pressure transducer for altitude encoding, an RF transmitter employing spread spectrum processing, a two-way RF transceiver, global positioning receiver, and an interfacing microprocessor. The weather data transmitted to the central station for processing may include temperature, relative humidity, altitude, wind speed and direction, data collection time, and data collection date.

[0008] A method aspect of the invention may include carrying a first weather station by an aerostat for providing altitude area weather data and tethering the aerostat to a selected aerostat altitude environmentally coupled to a ground target upon which chemicals are to be applied. A second weather station may then be positioned at a ground location environmentally coupled the ground target for providing ground area weather data. An aircraft having chemicals to be distributed may be provided with a flight plan to meet a prescription distribution of the chemicals and the plan may then be based on ground level and aircraft level weather communicated to the aircraft.

[0009] In yet another method aspect of the invention, the aerostat may be tethered from an initial altitude to a preselected altitude through intermediate altitudes in between. Altitude and ground area weather data nay then be analyzes at the various altitudes through which the aerostat is moved, and the aircraft altitude may then be changed to a preferred altitude for the chemical distributing based on the altitude and ground area analyzing. Yet further methods include the aircraft communicating with both the first weather station and the second weather station.

[0010] Another method aspect of the invention may include carrying a first weather station by an aerostat for providing altitude area weather data, positioning a second weather station at a ground location environmentally coupled the ground target for providing ground area weather data, receiving altitude and ground weather data transmitted from the first and second weather stations at a central communications station, and tethering the aerostat to a first aerostat altitude environmentally coupled to a ground target upon which chemicals are to be applied. Altitude area and ground area weather data may then be transmitted to the central communications station. The aerostat is then tethered at a second aerostat altitude environmentally coupled to a ground target upon which chemicals are to be applied. The tethering and communicating may then be repeated for communicating altitude area and ground area weather data to the aircraft. The aircraft altitude may then be adjusted to the aerostat altitude if appropriate for controlling the distribution of chemicals to the ground target.

[0011] The weather data from the altitude and ground positioned weather stations may be synchronized and include temperature, relative humidity, altitude, wind sped and direction, data collection time, and data collection date, and the data may be transmitted at least once every second.

[0019] The present invention will now be described more fully with reference to the accompanying drawings in which preferred embodiments of the invention are shown and described. It is to be understood that the invention may be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein. Rather, the applicant provides these embodiments so that this disclosure will be thorough and complete, and will convey the scope of the invention to those skilled in the art. Like numbers refer to like elements there through.

[0020] As illustrated initially with reference to FIG. 1, one preferred embodiment of the present invention includes a system 10 for controlling a prescribed application of chemicals from an aircraft 12 onto a ground target 14. A first weather station 16 is positioned at a preselected altitude 18 and a second weather station 20 is positioned generally at ground level, preferably at or near the ground target 14. A central communications station 24, which may be carried within a mobile ground unit 25 or by way of example optionally in the aircraft 12, communicates altitude and ground weather data with the first and second weather stations 16, 20 and provides weather information to the aircraft 12 for effecting an appropriate distribution of chemicals from the aircraft to the ground target 14 based on real-time weather conditions at ground level 22 and at an aircraft altitude 26.

[0021] With continued reference to FIG. 1, an aerostat, herein described in one preferred embodiment comprising a helium gas balloon 28, is carries the first weather station 16 for positioning it at the preselected altitude 18. A winch 30 is positioned at ground level 22 and is operable with a tether 32 carried on a reel 34 of the winch at one end and attached to the balloon 28 at the other for controlling the altitude of the balloon. Optionally, the first weather station may be carried by a tower of other similar structure for positioning it at the preselected altitude.

[0022] With reference now to FIGS. 2A and 2B, each of the first and second weather stations 16, 20 comprise sensors 17, 21 that may include a magnetometer configured as a directional compass 36, an anemometer 38 for determining wind speed, a solid state or other appropriate temperature sensor 40, a solid state or other appropriate humidity sensor 42 for measuring relative humidity, and a solid state aneroid or other pressure sensor/transducer 44 for altitude encoding, all of which provide weather related data to a processor 46 that processes input data and transmits the data through a two way RF transceiver/RF data link 48. The processor 46 is also operable for communicating with the sensors 17, 21. For improved signaling and data transmission to the aircraft 12, the first weather station 16 preferably includes an RF transmitter 50 employing spread spectrum processing. A global positioning receiver 52 is carried by the second weather station 20, preferably positioned at ground level 22 proximate the ground target 14 for providing a reference position useful in programming a flight plan for the aircraft 12. The weather data transmitted to the central station 24 for further may generally include temperature, relative humidity, altitude, wind speed and direction, data collection time, and data collection date.

[0023] The aircraft 12 preferably includes a guidance system 54, as illustrated with reference to FIG. 3, which may communicate with the weather stations 16, 20 and the central communications station 24. As illustrated by way of example, the guidance system 54 may operate with an onboard navigation system 56 for positioning the aircraft 12 proximate the ground target 14 and for following a prescribed flight pattern 57, as illustrated by way of example with reference to FIG. 4A, over the ground target 14 during the distribution of chemicals. As earlier described with reference to FIG. 2A, the aircraft 12 receives data directly from the spread spectrum data transmitter 50 of the first weather station 16 by the receiver 60 of the guidance system 54. As illustrated with reference to FIG. 4B and by way of example, weather conditions can dramatically affect the distribution of chemicals dropped from the aircraft 12. The guidance system 54 operates to provide the prescribed flight pattern 58 and an appropriate modified pattern 62, resulting from processing of weather data earlier described, as illustrated with reference, by way of example, to FIG. 5 using processed weather data from the off aircraft stations 16, 20 and flight pattern software which provides information from the processors 64 of the onboard guidance system 54. With reference again to FIG. 3, the guidance system 54 provides precision guidance to a pilot of the aircraft 12 including obstacle awareness, flight recording and displays, meteorological data on a real-time basis and for a target area of interest. By way of example, the onboard guidance system 54 may provide tactical, strategic, and real-time support as follows:

[0024] Tactical: (mission critical tasks and safety)

• • [0025] 1. Precision flight guidance
  • [0026] 2. Obstacle awareness
  • [0027] 3. Heads-up display
  • [0028] 4. In Pilot's field of vision

[0029] Strategic: (system capabilities not critical to safety of flight)

[0030] Real-time wind speed and direction

• • [0031] 1. Status of spray off/on, proportional flow and spray system pressure
  • [0032] 2. Error conditions-spray switch on, low flow, low pressure
  • [0033] 3. Temperature inversion warning
  • [0034] 4. Wind shift warning
  • [0035] 5. Additional hardware displaying spray area, no spray zones, both optimized coverage and intended target (wind corrected gridlines)
  • [0036] 6. Real-time wind speed, direction vectors provided
  • [0037] 7. Statistical display of mission performance (gallons sprayed, gallons remaining, acres treated, spray time, total mission time
  • [0038] 8. Mission specific enunciators display on heads-up screen.

[0039] In one operation and as illustrated with reference again to FIG. 1, the first weather station 16 is tethered by the balloon 28 at the preselected altitude 18 and generally near the target 14 for providing weather data to the aircraft 12. The second weather station 20 is positioned at ground level 22 and generally below the first weather station 16 and at or near the target 14 for providing ground area weather conditions. The weather conditions at the preselected altitude, generally about 300 feet more or less, and the weather conditions at ground level are used to provide optimum conditions, by possibly modifying the planned prescription, for distributing the chemicals from the aircraft 12 at that specific time.

[0040] In yet another operation, the balloon 28 is tethered from an initial altitude to a second altitude while monitoring and recording weather data through intermediate altitudes. By way of example, and with reference again to FIGS. 4A and 5, the prescribed flight pattern 58 is changed to the modified pattern 62. The aircraft altitude may then be changed to an intermediate altitude for the chemical. By way of example, the aircraft altitude is changed from a planned 300 feet to a modified 250 feet; the direction is modified; and the swath 66 is modified, all based on the real-time conditions. Preferable, the weather data from the altitude and ground positioned weather stations may be synchronized and include temperature, relative humidity, altitude, wind sped and direction, data collection time, and data collection date, and the data may be transmitted at least once every second.

[0041] By way of further example, the FIG. 4 depicts a typical spray mission where the approved target 14 is a 7 mile×4.1 mile block. Wind at 10 mph is in a direction perpendicular to the longest gridline. Spray altitude is 300 ft. While the insecticide is released from the spray aircraft 12 over the target area, the 20–30 micron average particle is most likely deposited outside the target area.

[0042] As illustrated with reference to FIG. 5, one spray mission may include an identical target area and weather condition. However, by optimizing the real-time weather data and mission correction controller, the altitude is lowered to 250 ft. and swaths are increased to 1300 ft. apart depositing the 20–30 micron particles in the target area.

[0043] By way of further example, one embodiment of the weather statistics useful during mosquito control of chemical/insecticide application may be described by:

[0044] Physical Dimensions:

[0045]

Helium Balloon	16′ × 6′ (widest) × 7.2′ fin width/height)
	292 cubic feet
Airborne Instrumentation	17.5 cm × 15.7 cm × 10.1 cm
Ground Instrumentation	17.5 cm × 15.7 cm × 10.1 cm
Ground Station Platform	Elevation range 6′–13.3′
Ground base tether	Elevation range up to 300′
Wind speed sensor	12 cm diameter cup wheel assembly
	40 mm diameter hemispherical cups

[0046] Performance:

[0047]

	Wind speed specification
	Range	0 to 112 mph
	Turning factor	75 cm
	Distance Constant	2.3 m
	Threshold	1.1 meters per second (2.5)
	Output frequency	1 contact .75 m/s per Hz.
	Wind Direction specification
	Range	360 degree mechanical
	Sensor	16 cm turning radius
	Transducer	Precision conductive plastic
		potentiometer 10K ohm
	RF Transceiver	433 MHz
	Spread Spectrum Transceiver	900 MHz range
	Computer processor	133 MHz
	Memory	32–300 SRAM
	On-board battery monitor

[0048] One embodiment of the guidance system 54 may include:

• • [0049] Use of 3–133 MHz microprocessors
  • [0050] Memory 32–300 mb SRAM
  • [0051] 900 MHz Spread Spectrum Transceiver 20+ mile range
  • [0052] Vacuum Fluorescent Graphics display
  • [0053] 7 key back lit keypad user interface with 16 intensity settings
  • [0054] Redundant encoder user interface on front panel
  • [0055] Redundant Pilots control yoke interface
  • [0056] Anti-glare display filter
  • [0057] Obstacle avoidance database on compact flash card
  • [0058] Pre-planned spray mission on Compact flash card
  • [0059] Power 9–30 volts DC
  • [0060] Three 4–20 mA inputs
  • [0061] One Timer input (Pulse input)
  • [0062] On-board 8-channel GPS receiver
  • [0063] RTCM 104 differential GPS correction available
  • [0064] Two Serial ports
  • [0065] External Light RS232 Communication
  • [0066] Two Analog Inputs

[0067] Such an embodiment may:

• • [0068] Provide instantaneous real-time weather data at ground level.
  • [0069] Provide instantaneous real-time weather data at desired aircraft altitude.
  • [0070] Transmit all meteorology data every second to the data recorder.
  • [0071] Transmit all meteorology data every second to the personal computer.
  • [0072] Transmit all meteorology data every second to the application aircraft.
  • [0073] Provide location (Lat/Long) of the balloon to application aircraft every second.

[0074] By way of yet further example, while deploying the balloon and when at a desired altitude, the aerial instrumentation may transmit weather data including time/date, altitude, temperature, humidity, and wind velocity by way of a 433 MHz RF transceiver to the ground instrumentation. The ground RF unit receives the aerial weather data and packages it with the ground weather data including the balloon location into a data pack, which is then transmitted back to the aerial unit through the 433 MHz RF unit. When the aerial instrumentation receives the entire weather data pack, it is then transmitted using the more powerful 900 MHz spread spectrum transceiver to either a ground receiver (PC) or to the aircraft in flight. This data is transmitted once per second.

[0075] Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and alternate embodiments are intended to be included within the scope of the appended claims.