Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
  • G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
  • G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
  • G01S19/40—Correcting position, velocity or attitude
  • G01S19/41—Differential correction, e.g. DGPS [differential GPS]

Definitions

• the present invention relates generally to apparatus and methods of use of satellite-generated signals for locating, positioning, guiding and tracking ground and airborne vehicles, and, more particularly, to an improved global positioning system with differential correction for providing highly accurate swath-to-swath guidance for agricultural equipment and devices, including a light bar to provide even more precise guidance for the operator to position himself on the next swath in the pattern and a controller to automatically continuously monitor vehicle ground speed and position and to adjust and maintain the flow of agricultural products over a specific land area at the desired rate.
• Paper flaggers are tightly folded packets of cardboard and tissue paper which, when released from an ejector mechanism on the aircraft, unfold in the airstream and flutter down to earth in a long, white streamer leaving a visible marker for the pilot to use in locating his last flight path over the ground. This becomes his reference in estimating a proper displacement to his next desired swath.
• Foam Dispensing Devices Another visual technique for establishing spacing and guidance is the so-called foam dispensing system. Utilized primarily in ground spray applicators, this technique relies upon a pair of flexible hoses dangling from the far ends of the spray boom. As the spray rig moves through the field, the operator presses a button in his control cab to activate a valve which releases a small volume of foam, very similar to shaving cream. These foam discharges are spaced at intervals several seconds apart and are used by the operator on his next swath to determine his proper position with respect to the last swath.
• a further major disadvantage of such laser-based systems is that they are geographically limited. Any vehicle carrying laser-emitting guidance equipment must operate within the geographic bounds of a finite number of reflectors which enable the on-board equipment to carry out the necessary positional calculations. The same limitations apply when the reflector is the on-board equipment and the laser emitting sources are on the ground. In effect, the mobile unit is captive to an area described by a line-of-sight beam linking the laser emitter with at least two dedicated and carefully installed reflectors.
• d. Radar/Transponder Similarly limited in terms of its operating area is the radar/transponder technology which has been developed and marketed by several vendors.
• the vehicle aircraft
• the vehicle is equipped with a radar transmitter and a receiver which receives signals from multiple stationary transponders located so as to provide a triangulation fix to the vehicle's on-board computer.
• the on-board computer calculates a reasonably accurate ground track and speed.
• the radar systems are absolutely limited in range to an area covered by the line-of-sight to at least three, and preferably four, system transponders. Also, the cost of installing and maintaining such a system is often prohibitive, and the prospect of multiple operators sharing the same tri-sponder system is impractical due to system degradation from concurrent use by multiple vehicles. A further major problem is lack of reliability. If one transponder fails, one battery dies, one lightning strike takes its toll, then the entire system is disabled. Thus, in actual experience, these so-called tri-sponder systems have been widely tried throughout the agricultural industry, but have failed to gain acceptance.
• a further electronic system used to assist a pilot in swathing operations to find his next swath is a LORAN-C navigation system for macro-positioning assisted by a needle gauge or light bar for micro-positioning.
• the Loran-C system was well known for maritime and airborne general navigation.
• the light bar typically was an instrument placed in an aircraft and had a single row of three multi-color lights. See, for example, the Davidson '226 patent, supra.
• Such prior light bars are in effect the same as a needle type turn indicator or audible tone series well known to aviators.
• GPS Positioning System
• GPS receivers and related equipment have undergone a rapid price reduction as utility and popularity of the technology has mushroomed.
• Current pricing for highly accurate, differentially corrected GPS equipment is well within the bounds of sound economic return.
• Base reference stations for providing differential corrections to enhance the accuracy of basic GPS, and even the broadcast differential correction messages themselves are also now priced to be within the economic reach of a large segment of the agricultural community.
• DGPS differentially corrected GPS
• Typical prior GPS and DGPS ground and airborne applications have included, for example, a system to Stepman (U.S. Patent 4,667,203) which determined position information between fixed points on the earth by measuring the phrases of the GPS satellite transmitted carrier signals without knowledge of the transmitted codes; a system to Chisholm (U.S. Patent 4,866,450) timing GPS signals transmitted by a fixed station to develop range information for receiving aircraft in an instrument landing system; a system to Joquet (U.S. Patent 4,894,655) which used DGPS signals transmitted by a fixed station to enable a rover to estimate its position corrected by the correction data in a microwave landing system; and a method to Allison (U.S.
• Patent 5,148,179 which used DGPS signals to position the rover relative to the fixed base by using dual frequency phase corrected carrier signals.
• GPS or DGPS have not heretofore been used to accurately position agricultural ground or airborne vehicles or to monitor and control the amount and rate of agricultural products dispensed by such vehicles.
• One aspect of the invention is in a rover guidance system for determining position from satellite signals which includes a receiver for receiving signals from a plurality of satellites in a GPS constellation to determine a position of the rover over the earth, and for receiving data from a base radio to correct the position, and a computer to calculate a corrected position of the rover from the correction data wherein the improvement is means for using the corrected position to guide the rover in an agricultural swathing operation.
• the system continuously displays the corrected position enabling an operator to guide the rover.
• FIG. 1 For purposes of this form of the invention, defining swath width and a right or left swath pattern layout, defining an A-B reference line for the swath pattern and computing a field layout in successive, parallel, equally spaced tracks in the direction preselected by the operator, defining a width of a field and computing field layout therefrom, using a keypad for inputting predetermined parameters, recording the positions traversed during the operation and reproducing the recorded data as a map of the field swathed.
• a second aspect of the invention is a dual row lightbar for guiding a rover relative to a centerline which includes a display of rover lateral displacement from the centerline in one row, and a display of rover intercept angle with the centerline in the other row.
• the lights in the lightbar are preprogrammable so that when the lights are illuminated, rover deviations from the centerline are indicated in units equivalent to rover lateral displacement from the centerline in direction and amount and angle of intercept with the centerline in direction and amount.
• Still another feature of this aspect of the invention is the lightbar having a front transparent window covered by a circular polarized material affixed thereto supported in the housing at an upward angle relative to a horizontal plane substantially perpendicular to a front face of the lightbar such that the first reflection is of the dark inner roof of the lightbar whereby the readability of the lightbar is substantially enhanced even in direct sunlight.
• a third aspect of the invention is a rover dispensing system which includes the DGPS receiver, and a flow controller for varying the amount of dispensed product as a function of rover ground speed and rover actual position over the earth determined by the DGPS to provide a predetermined amount of the product.
• Fig. 1 - Is a schematic view of an overall DGPS agricultural ground and aerial system of the present invention.
• Fig. 2 - Is a plan view of a typical computer generated map of a farm field spray pattern resulting from using the present invention.
• Fig. 3 - Is the computer generated field layout according to the algorithm used in the present invention.
• Fig. 4 - Is a plan view of the right back-to-back flight pattern pre-selectable by the operator of the present invention.
• Fig. 5 - Is a plan view of the right racetrack pattern pre-selectable by the operator of the present invention.
• Fig. 6 - Is a plan view of the right squeeze pattern pre-selectable by the operator of the present invention.
• Fig. 7 - Is a partial schematic block diagram of the DGPS and lightbar components of the system of the present invention.
• Fig. 8 - Is a schematic view of the two types of antennas used in the present invention.
• Fig. 9 - Is a side elevation view of the cpu/GPS unit of the present invention with PCMCIA card.
• Fig. 10 - Is a front elevation view of the power supply/data receiver of the present invention.
• Fig. 11 - Is a plan view of a PCMCIA Memory Card used to record the data describing the flight path traversed during a mission using the present invention.
• Fig. 12 - Is a plan view of the keypad box of the present invention.
• Fig. 13 A- Is a plan view of the display box of the present invention.
• Fig. 13B- Is a plan view of the swath screen of Fig. 13 A.
• Fig. 13C- Is a plan view of the navigation screen of Fig. 13 A.
• Fig. 13D- Is a plan view of the satellite screen of Fig. 13A.
• Fig. 13E- Is a plan view of the program screen of Fig. 13 A.
• Fig. 13F- Is a plan view of the waypoint screen of Fig. 13 A.
• Fig. 14A- Is a plan view of the dual row lightbar of the present invention.
• Fig. 14B- Is a schematic representation of simulated flight paths that can be digitally represented by the right digital readout of the light bar of Fig. 14 A.
• Fig. 14C- Is an enlarged view of the three center lights in the top row of Fig.l4A showing the color of three lights.
• Fig. 14D- Is one example of a lightbar presentation for a hypothetical situation.
• Fig. 14E- Is a second example of a lightbar presentation for a hypothetical situation.
• Fig. 14F- Is a third example of a lightbar presentation for a hypothetical situation.
• Fig. 14G- Is a right side elevation cross-sectional view of the lightbar of the present invention.
• Fig. 15 - Is a table relating a suggested correlation between angle-of-intercept and off-track position for three types of sensitivity levels for preprogramming the upper and lower lightbar settings of the present invention.
• Fig. 16 - Is a schematic block diagram of a prior art flow controller.
• Fig. 17 - Is a partial schematic block diagram of the flow controller of the present invention.
• Figs. 18A and 18B - Are operational flow charts of the process of the present invention.
• the primary function of the AirStar with flow controller system is to provide airborne computerized DGPS agricultural product dispensing with real time parallel swath guidance and control of aerially sprayed products.
• the system also
• TM provides a wide assortment of related functions. Its sister product, Terrastar , is for ground applications. The present detailed description is limited to the AirStar system.
• the overall system 10 derives its navigation and guidance capability from a constellation of up to 24 NAVigation Satellite Timing And
• Ranging("NAVSTAR") satellites 10,800 miles above the earth, which continually broadcast coded messages.
• base station GPS receiver 9 base station GPS receiver 9
• the GPS receiver 9 when coupled with conventional special purpose computer software and hardware provides precise vehicle relative positioning and guidance with unparalleled accuracy.
• Each GPS satellite may be identified by its transmitted signal which also provides to users the positioning, timing, ranging data, satellite status and the corrected ephemerides (orbit parameters) of the satellite.
• the GPS satellite positions received and computed by the Novatel GPS receiver used in the present invention are accurate to within about
• the fixed base's position is a known latitude and longitude, it can now compare its computed range measurements from the GPS signals to that of its actual known ranges. The difference between the calculated ranges and the known ranges is largely accounted for by the previously mentioned external bias errors.
• the fixed base now transmits computed range corrections over an established data link to the rover station.
• the rover whose position is of unknown accuracy, will then correct its position solutions to reflect the fixed base differential corrections and its position solution accuracy will approach that of the fixed base because when the rover station receives the differential corrections, they are directly applied to its range measurements which cancels most of the bias errors as was the case at the fixed base.
• GPS Receiver used in the present invention may be obtained by referencing the Novatel GPS Receiver User Manual dated October 28, 1992, Revision 1.0, pages 75-77, copyright
• TM in the present invention may be obtained by referencing the Novatel GPSCarD OEM
• base 9 compares the received signals 5 representing its measured position on the earth with its stored known latitude and longitude and calculates an error signal 6 representing the difference ("differential correction") which it broadcasts via antenna 12 to airborne rover 13.
• Rover 13 also receives the GPS satellite signals 5 via round antenna 14 and the differential correction signals with Forward Error
• rover 13 is within 200 kilometers of base 9 the differential correction for both base 9 and rover 13 are the same, and rover 13 can accurately fix its position within centimeters of its actual position over the earth.
• Land rover 16 receives the same signals 5,6 as aforesaid via antennas 17, 18 respectively.
• the range of the base 9 transmitter may be extended by repeater 20 located on a nearby mountain which receives signals 6 and retransmits them as signals 7 which repeater 21 may receive and retransmit in the well known "digi-peater process".
• Rovers 13, 16 spray agricultural products via a swathing process the accuracy and efficiency of which is significantly enhanced by the present invention, as more fully described below.
• an area map 20 is shown in which field 21 was located and sprayed using a swathing pattern 33 developed by the present invention. Obstacles around the field include silo 23, house 24 and trailer park 25 to the north; pump 26 and garden 27 to the east; pump 28 and canal 29 to the south; and, equipment yard 30 and poles 31 to the west.
• the field is surrounded by roads and telephone lines on all sides.
• the on-board DGPS receiver and light bar of the present invention located the field, guided the pilot to entry point 22, computed the swath pattern, guided the pilot precisely to and along each swath, monitored position and ground speed while dispensing the pre-selected amount of fertilizer per acre, guided the pilot to departure point 32 and navigated him home.
• the area map 20 showing the complete actual path flown over the ground and printouts showing all of the other related flight data were printed within minutes after touchdown.
• the AirStar system is capable of providing guidance to any selected waypoint (entered into the system using latitude and longitude coordinates); displaying position, altitude, speed and heading information; informing the pilot of distances with respect to manually entered line end points; and also gives an indication of being within a defined closed area of up to 17 sides.
• the AirStar system assists the pilot in spraying operations by providing, for example, GPS/flux gate compass derived wind speed and direction, preprogrammed swath pattern definitions, distance to field entry and exit, real time display of the number of acres sprayed, and two programmable digital light bar displays for indication of ground speed, true heading, swath number and lateral displacement from and angle of intercept with desired swath path.
• the addition of the flow controller allows the AirStar system to monitor and control the spray system and display flow in gallons per acre and total gallons remaining. To facilitate post flight analysis and provide a permanent record of spraying operations, a complete data log of time, position, altitude, ground speed, spray on/off and flow status, and wind speed and direction is recorded by the system.
• the AirStar system is a very versatile system capable of flying a field or spray area of any shape, and establishing parallel swaths of unlimited length.
• the A point of Fig. 3 is entered into the AirStar system by the pilot's aligning the aircraft with the desired reference edge of the field or area of interest and depressing the ABC Swath Advance button 68 (see Section 3e(l l) infra.) on the keypad 60 exactly when the aircraft is over the beginning of the area to be sprayed.
• the light bar 46 will now begin flashing all of its lights solid red, then solid green, at a frequency of several flashes per second. This flashing will continue until the B point is defined.
• the B point of Fig. 3 is entered into the AirStar system by the pilot's depressing the ABC Swath Advance button 68 on the keypad 60 one time exactly when the aircraft is over the point at which spraying is be terminated.
• the pilot merely pushes the same button (ABC Swath Advance 68) each time he finishes a swath (including the A-B line, which is swath #1) and the system provides guidance to the next swath (as more fully described below).
• the computer 41 numbers the swaths successively as shown in Fig. 3:
• the A-B line is swath #1, followed by 2, 3, 4, 5, etc. This selection of LEFT or RIGHT must be done prior to laying down the A-B line.
• the pilot may desire to fly any of several possible swath patterns.
• One pattern is to fly from one swath to the next in succession.
• Another is to skip adjacent swaths by advancing to a larger numbered swath and then returning to a lowered number swath in succession.
• the AirStar system allows the pilot to specify three possible spray patterns:
• the back-to-back pattern shown in Fig. 4 allows the pilot to fly consecutive numbered swaths in succession.
• the A-B line is swath #1 followed by 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. in order.
• This pattern is set up normally during completion of the quick-start checklist by first pre-setting Swath Width in the Program Screen 130 and then selecting Back-to-Back with the Pattern button 80 and Right or Left with the Left/Right button 70, on the Swath Screen 100.
• RIGHT BACK-TO-BACK is illustrated in Fig. 4. ((2)).
• Racetrack The racetrack pattern shown in Fig. 5 allows the pilot to initially fly each end of a field and then alternately work from the A-B line to the middle and from the middle toward the C line (other end of the field). For the 12 swath field shown in Fig. 5 the order of flight is 1, 12, 2, 7, 3, 8, 4, 9, 5, 10, 6, 11.
• RIGHT RACETRACK is illustrated in Fig. 5.
• This pattern is set up during completion of the quickstart checklist by first selecting Racetrack with the Pattern button 80 on the Program Screen 130, and then Right or Left with the Left/Right button 70 on the Swath Screen 100.
• the pilot establishes an A-B line (as in the Back-to-Back example above) and then flies Right (or Left as preselected) to the far end of the field (display 90 will be showing "Waiting-C" and defines the width of the field for computer 41 by depressing the ABC Swath Advance button 68 thereby establishing point C of Fig. 5.
• the computer now recognizes the width of the field as the distance from the A-B Line to the C Line and divides the field into equal halves.
• the A-B line is swath 1, and the
• C line is swath 12.
• the pilot depresses the Swath Advance button 68 and receives guidance to swath #2, followed by again depressing the Swath Advance button 68 and receiving guidance to the swath #7, the centerline of the field. Each successive swath is alternately to the right of the A-B Line, and the centerline until the field is complete.
• the computer keeps track of the progress. The pilot knows the field is complete when pressing Swath Advance 68 gives guidance back to swath #2, which was previously completed.
• the squeeze pattern is set up in the same way as the Racetrack pattern, i.e. Squeeze is preselected on the Swath Screen 100 when completing the quick-start checklist and then the A-B and C lines are established during flight.
• a different sequence of swaths is flown the computer 41 guiding the pilot to spray each side of a field, A-B and C, and then work each side, alternately, toward the middle.
• the swath sequence is 1, 12, 2, 11, 3, 10, 4, 9, 5, 8, 6, 7.
• RIGHT SQUEEZE is illustrated in Fig. 6.
• the SATLOC AirStar system is a complex system, electronically.
• the pilot only needs to set the desired swath width, type of pattern, and direction of turn after the first swath. Thereafter until the completion of the field, it is simply a matter of finding the field, using one switch (the A-B/Swath Advance button 68 which is usually on the stick) at the entry and exit points for the first swath, and the same switch to advance to the next swath, with guidance.
• the system gives direction of turn, keeps up with swath number, and tells the pilot how far to go to be on the swath.
• the AirStar system includes a round antenna 14, a whip antenna 15, a computer and GPS receiver unit 41, a radio receiver with data modem and power supply unit 42, a removable memory card 43, a keypad box 44, a cockpit display box 45, and a light bar display 46.
• the components are contained in custom made metal boxes connected in modular fashion by military style circular connectors to facilitate various configurations and easy component replacement. All boxes are sealed with rubber gaskets to prevent moisture and chemical corrosion of the internal electronic components. The following sections describe in detail the various components which make up the AirStar system.
• the AirStar System a. Antennas As seen in Fig. 8, the AirStar system utilizes two antennas. A round low-drag aircraft type GPS antenna 14 for detecting the satellite signals 5 in the 1.57542 GHz range (FAA C115a approved) and a 900 MHz range whip antenna 15 for receiving differential correction transmissions 6 from base 9.
• a round low-drag aircraft type GPS antenna 14 for detecting the satellite signals 5 in the 1.57542 GHz range (FAA C115a approved) and a 900 MHz range whip antenna 15 for receiving differential correction transmissions 6 from base 9.
• the computer and GPS unit 41 includes a conventional 80386 DOS computer (not separately shown) and a conventional GPS receiver (not separately shown) with PCMCIA solid state memory card 43.
• the function of this unit 41 is to receive the GPS signals 5 from antenna 14 and the differential correction signals 6 from the differential correction radio receiver 42 (described below) and antenna 15, run the parallel tracking and guidance software in conjunction with the keypad 60, display 90 and lightbar 46 (described below), and log the flight and spray operations to the PCMCIA memory card 43.
• the AirStar computer manufactured by Zykronix Inc., is a 4"x6" miniature CPU board with an 25 or 33 MHz 80386 processor and 80387 math coprocessor with two MBytes of memory. Additional devices on the main CPU card are the keyboard, two serial ports, one parallel port, a floppy disk drive and a hard disk drive. Two smaller boards (4"x3.5") attach directly on the top of the CPU board in a stacked fashion to support a PCMCIA Type 1 solid state memory card 43 interface and a GPIO card which has two additional parallel and serial communication ports and sound input and output using twelve bit A/D and D/A conversion.
• the PCMCIA memory card 43 contains the software program and data logs.
• the DOS operating system resides in a bootable read only memory chip.
• a color VGA screen for a moving map is easily supported by the addition of a 4"x3.5" VGA card to the existing stack and appropriate display software.
• the GPS receiver in unit 41 is manufactured by NovAtel Communications Ltd. and is contained on a single 7"x4" board. This conventional high performance receiver is capable of tracking 10 satellites simultaneously and outputs position and speed information every 200 msec.
• the GPS receiver is a civilian narrow correlation type and with the timely GPS differential correction data supplied by data radio link 42 described below provides rover 13, 16 actual position with an accuracy within one meter. With no pre-knowledge of time or position the GPS receiver in unit 41 tracks satellites and outputs position within two minutes from power up. GPS signal re-acquisition, after loss due to shading of antenna 14 by the aerial rover 13 in steep turns, is typically under five seconds once the shading is removed.
• the computer (CPU) power supply converts and filters DC voltages for the GPS receiver and PC card set. Attached to the computer power supply is an interface printed circuit board which provides connection for the rest of the AirStar system components including the power supply/radio modem 42, keypad box 44, display box 45, lightbar 46, and a VGA display.
• c. Power Supply/Data Radio Receiver Unit As seen in Fig.10, an integral part of the AirStar system is the power supply and data radio receiver unit 42.
• the power supply converts aircraft or other vehicle power 47 to meet the specific requirements of the operating components.
• the data radio receiver (not shown separately) is typically a 450 or 900 MHz data radio which receives the differential correction signals from base 9 via antenna 15.
• Unit 42 provides the data links 48,49 through which differential correction data, spray system data, wind direction and velocity data, and other monitor and control data is routed.
• the AirStar' s main power supply 42 converts 18-40 volt DC aircraft voltage to 5, 12 and -12 volts DC for the various electronic sub-systems. This unit is fully protected by a crowbar type fuse circuit and a 7.5 amp blade type fuse.
• the modem (not separately shown) portion of the data radio receiver uses conventional forward error correction (“FEC”) technology to extend the effective range to which data integrity is maintained.
• FEC forward error correction
• mobile communication signals increasingly fade with distance from the transmitter due to destructive interference known as "multipath fading”, and the effective range can be increased by the FEC technique of introducing redundant information into the data stream combined with interleaving.
• Applicant's unique FEC code introduces 50% overhead (redundant information and interleaving) which lowers the net data rate to 66.6% of the channel rate and satisfactorily extends operating ranges to 100 or more kilometers.
• the radio interface in unit 42 is capable of supporting two-way AirStar specific position and other data transmitting and receiving. This feature allows both messaging and addressability type receiving of special data from a central dispatch office. The position reporting feature is particularly useful for real time tracking purposes. Additional interfaces connected in the power supply unit 42 and routed to the
• CPU 41 via the GPIO cable 49 include the spray on/off sensor, the flux gate compass, the spray sentinel flow control device, and a special line endpoint/swath advance switch which is usually mounted on the pilot's joystick. GPS data output is available for future expansion of the AirStar functions if necessary. Twelve volt and five volt DC power are also available for the flux gate compass and the spray sentinel respectively.
• PCMCIA Memory Card As seen in Fig. 11, a 2-megabyte, PCMCIA card 43 is included as standard equipment with each AirStar system. Cards with increased memory capacity are available as options. Cards are not interchangeable between AirStar units.
• the keypad box 44 is a housing for a custom 4x5 key matrix with a single labeled membrane. Additional devices mounted on the keypad box 44 are the main system on/off switch 51, a headphones jack 52 for sound output, rheostat 53 for keypad 60 backlighting and display 90 brightness, rheostat 54 for lightbar 46 lights 151, 153, 156, 157 and digital outputs 156, 157 brightness, rheostat 55 for audio output volume and a twenty button keypad 60 for setup and operation of the system.
• the twenty button keypad 60 controls:
• the keypad 60 incorporates the ability to manage the many functions of the system. The basic functions required for successful use in flight are programmed prior to take-off. The operation in flight is reserved to one or two keys, most of which can be incorporated into the pilot's stick grip.
• the pilot programs swath width and lightbar settings on the ground. On take-off the pilot flies to the desired entry point. Upon arrival at the field to be sprayed, the pilot evaluates the wind conditions and then programs the type of pattern and the right or left direction of progression from the A-B Line. He squeezes the trigger switch (function of ABC/Swath Advance button 68 on keypad 60 can be programmed into the pilot's stick grip) on the stick grip to set point A, the same switch to set point B, and the same switch to advance to the next swath.
• the trigger switch function of ABC/Swath Advance button 68 on keypad 60 can be programmed into the pilot's stick grip
• the pilot When the field is done, the pilot simply hits the CLEAR/RESET button 76 on the keypad 60 and starts a new field, just as above. If a different pattern is required, he toggles the PATTRN switch 80 on the keypad 60 and toggles the Left/Right switch 70 for right or left direction of turn.
• the operational logic of the Keypad 60 which control inputs to computer 41 is as follows: 1.
• the numerical/function keys 65-67, 69-71, 73-75, 78 (numbered 1, 2, 3,
• the function keys 68, 72, 76, 77, 79, 80 have specialized/multiple functions to be discussed below.
• the function of each control on keypad box 44 and of the twenty buttons on keypad 60 shown in Fig. 12 are described below:
• the phones jack 52 is located below the power switch 51 and is used to plug in the headphone connection when audio output is installed.
• the KEYPAD and LIGHTBAR rheostats 53,54 respectively control the brightness of keypad 60 and lightbar 46 lights.
• the AUDIO rheostat 55 adjusts headset volume when audio output is installed.
• Set SET button 61 sets Spray Sentry 170 Operation when installed. If installed, the SET button is used to save entries which are made in the View button 62 menu. If pressed in any other mode the display 90 reads:
• View View button 62 enables viewing Spray Sentry 170 Operation data when installed.
• VIEW button 62 is depressed, the display 90 reads: GAL TOTAL 000
• Repeat Repeat button 63 repeats Spray Sentry 170 Operation when installed. If not installed, when the Repeat button 63 is depressed, the display 90 reads:
• Swath SWATH button 64 may be pressed at any time to return to the Swath Screen.
• the first depression of the HOME button 65 after turning the system on causes the current aircraft position (latitude and longitude to the ten thousandths of a minute, i.e., 32.54.2367) to be stored as the home point in Waypoint 1 in route 11 (see
• MARK button 69 to mark the spot for return and then press CLEAR.
• the lightbar 46 guidance to home point may be used. After loading, depress the RETURN button 75 and the marked pattern will be displayed for return to the field.
• a new cycle is initiated, i.e., the existing home position is lost, and a new home position is stored with the next selection of the HOME button 65.
• Depressing the PLOT button 66 toggles between PLOT ON and PLOT OFF.
• the system is programmed to optionally log vehicle navigation data for use in subsequent post flight software processing.
• the PLOT key 66 places an identification flag in the logged data that is time tagged and located via GPS. This flag continues to be set in the data record until the PLOT key 66 is depressed a second time. This flag is also used to mark the duration of an event i.e., when the vehicle spray system is on. The status is indicated by *SP* in the bottom row of the Swath Screen in place of — .
• This function may also be controlled remotely by the spray pressure system which may also be wired for automatic logging of the spray event.
• Depressing the POLY key 67 records a point in a polygon into memory.
• the pilot may define an area by pushing this button up to 17 times.
• the computer draws a polygon.
• the green AREA light 94 on the right side of the display 90 illuminates.
• the light 94 extinguishes upon exiting the area.
• An existing polygon is cleared by entering and then exiting the Waypoint Screen.
• a new polygon may be initiated by pushing the POLY key 67 again. Only one polygon can be stored at a time, and any point beyond 17 replaces the prior point 17.
• ABC ADV/UP Arrow Button 68 sets the A-B Line and the C Line, advances the swath number, and provides an arrow function which (1) scrolls upward in the Program Screen, and which (2) changes values which are toggled.
• Pressing the ABC ADV key 68 the second time will cause the aircraft location in the field at the time the key 68 was pressed to be stored as the "B" point in the swathing algorithm.
• the program gives guidance to the next swath centerline outside C. For example, let us assume that the pilot has flown the A-B Line and has then entered the edge of the field, i.e., the C line. By looking at the amount of swath offset in left window of the lightbar 46, the pilot can see how many feet it is to the outside swath centerline and decide whether or not to make the next pass on an inside swath centerline.
• the ABC ADV key 68 is also used to advance to the next swath after the A-B Line in the Back-to-Back pattern, and after point C in the RACETRACK OR SQUEEZE patterns have been established.
• the system defines the A-B Line as swath #1.
• the Up Arrow 68 is functional ONLY in the Program and Waypoint Screens. At that time it functions as follows:
• the MARK key 69 When the user wishes to record current position and swathing status to later return to a precise point in the field, the MARK key 69 should be depressed. This action stores to memory card 43 all current operational data, such as, A-B Line, type of pattern, direction of turn (right or left), swath #, and exact current position. This data can be recalled either before or after shutdown and restart by pressing RETURN.
• the system looks in its database for a point previously recorded as a mark. If it finds such a point, the system gives the range and bearing to return to it and, if MARK key 69 was selected while in a spray pattern, restores the status of the spray/swathing session as it was when the mark was saved. Depressing MARK key 69 will override any previously saved MARK data. (13). 5/Left-Right Depressing the 5 key 70 enters the number 5 in the SPRAY SENTRY 170, Program or Waypoint Screens.
• the pilot Before the operator defines the A-B reference line for subsequent swathing, the pilot must decide if the aircraft will be operated to the RIGHT of the A-B line or to the
• LEFT If the LEFT key 70 is pressed while the system is displaying "Waiting for A", the screen will display LEFT. Depressing the LEFT key 70 toggles between LEFT and RIGHT. The RIGHT key 70 is for selecting the Program Screen. If LEFT is selected, the system will lay out a grid of 999 lines to the left of the A-B reference line. If the operator desires to change the RIGHT/LEFT setting after the A-B line has been defined, the CLEAR/RESET key 76 must first be pressed, then the LEFT key 70 toggled to select LEFT or RIGHT as desired and then the A-B line reinstalled.
• DECR/Down Arrow Depressing the DECR button 72 decreases the swath number from that currently selected (opposite of ADV). This function is useful in that the pilot may advance swaths, say from 2 to 10, in order to avoid personnel in the field, and then decrease swath from 10 to 3 to resume the previous position. This button is also used to decrease swath number when pilot inadvertently advances more than one swath with the ADV (swath advance) button 68.
• the Down Arrow button 72 functions ONLY in the Program and Waypoint Screens. In the Program Screen it performs 2 functions:
• the DIM key 73 reduces the intensity of the display 90. Each depression reduces the brightness approximately by 30%. The fourth depression cycles the display 90 back to its brightest setting.
• ENTER - Exit If ENTER is selected, the Swath Screen comes up. No change has been made, i.e., the log file has not been purged and logging will continue automatically on the existing file.
• the message "Mins Left 1020" appears at the bottom of the screen and indicates how many minutes of operation can be logged before filling the memory card 43.
• the pilot must first install the desired return point by pressing the MARK key 69 at the point where the swathing operation terminated and then press the RETURN key 75 to get range, bearing and guidance back to that point.
• pressing the RETURN key 75 will cause the system to restore the program status to the state at which it was when the MARK key 69 was pressed. At this time, the lightbar 46 displays the distance off the desired track toward the marked point.
• the CLEAR/RESET key 76 serves as a delete key for items entered into the various program options.
• Pressing CLEAR/RESET key 76 will reset the computer swathing program irrespective of whether the aircraft is currently swathing. It removes all reference to the A-B line, and the current swath, as well as the display of cross track error on the light bar 46. When reset, the system displays solid yellow in lightbar 46 lights with no RED/GREEN lights irrespective of cross track error status.
• the RESET key 76 is used, the A-B reference line, the direction RIGHT or LEFT of swath, the swath PATTERN, and the SWATH WIDTH can all be reinputted.
• the ENTER function of key 77 is operable in the Waypoint and Program Screens.
• the ENTER key on a computer keyboard is used. Once a value has been selected for an option, or a selection from an option item has been implemented, the ENTER key 77 is depressed one time to input that value to the computer 41.
• the AirStar system incorporates a complete point-to-point navigation system. It is structured in routes and waypoints.
• the Route button 78 is functional when the Waypoint Screen is displayed, and when the button is depressed while in the Navigation Screen.
• the system can accommodate up to 12 preprogrammed routes, each containing
• Routes 1 thru 10 are available for the pilot to store up to 100 latitude and longitude positions.
• Waypoints 2 & 3 are used for programming a remote A-B line. Route 11, Waypoints
• a waypoint is a specific latitude and longitude position which is programmed by the operator into the Waypoint Screen. There are 10 available slots or entries in each one of the 12 Routes, for a total of 120 possible entries.
• Fig. 13 F shows Route 01, WayP (Waypoint) 03, ID (identification) SAT, and a specific latitude and longitude.
• ZERO is not permitted in naming ROUTES or WAYPOINTS. a. Scroll to each successive data block by depressing the ENTER button 77. b. To return to a previous entry, continue depressing the ENTER button 77, or, use left Arrow button 79.
• the ENTER key 77 or the DOWN ARROW key 72 must be pressed until the blinking cursor is on the first item of the latitude block.
• numeric keys are used to enter the latitude in degrees- minute-seconds format.
• a negative latitude is specified by toggling the N(North)/S(South) digit displayed in the Waypoint screen at the end of the latitude block with the
• the longitude is entered in the same fashion when the blinking cursor is on the longitude field.
• the user must press the SWATH key 64. Pressing the SWATH key 64 selects the last valid Waypoint and Route for display in the RANGE and BEARING fields of the main display screen (i.e., the swath screen).
• the LEFT ARROW key 79 permits the user to back the cursor through item selections in MENU or NAVIGATION/WAYPOINT modes.
• Routes 1 thru 10 can be used for any field, airport, or navigation point the pilot selects.
• the system provides for vehicle navigation over the earth. This feature can be used to select a set of pre-defined courses or routes. To organize the courses, the system allows 10 Waypoints consisting of latitude and longitude to be defined for each of 10 separate Routes. The Routes can be used to collect a certain set of Waypoints that are related, e.g., as many as 10 fields could be entered as Waypoints in NORTHERLY-Route 1. In addition, 10 in SOUTHERLY-Route 2, etc. (23).
• the PATTRN key 80 toggles between the BACK-TO-BACK, RACETRACK, and SQUEEZE patterns. The system will always boot up in the RIGHT BACK-TO-BACK pattern The RIGHT ARROW key 80 is not functional at this time.
• the display box 45 of the AirStar system houses a 20x4 character vacuum florescent Noritake display 90 for status, operator control, and data input.
• the display 90 is green and has software controlled brightness levels which make it suitable for night spraying.
• Also included in the display box 45 are four separate light emitting diodes ("LED") 91-94 which, when ON, indicate the following (from left to right in Fig. 13 A):
• the four-line digital display 90 provides information to the pilot through five separate screens 100, 110, 120, 130, 140, the first three 100, 110,
• Swath Screen 100 (Fig. 13B)- is automatically displayed on start-up. Press the SCREEN/ENTER button 77 to scroll to the Navigation screen. • Navigation Screen 110 (Fig.l3C)- is the second screen in sequence. Press the SCREEN/ENTER button 77 to scroll to the GPS Satellite screen.
• GPS Satellite Screen 120 (Fig. 13D)- is the third screen in sequence. Press
• Program Screen 130 (Fig. 13E)- is the fourth screen. Press the * button 71 to enter this screen. Press SWATH button 64 to exit to Swath Screen 100.
• Waypoint Screen 140 (Fig. 13F)- is the fifth screen. Press the WPT button
• the Swath Screen is the first screen to be displayed after the system is powered up, and Built-In-Test/GPS Initialization is completed. With the system properly programmed (via the Program Screen 130), all the information necessary to spray a field, with parallel tracking & guidance is displayed.
• the screen has three possible formats of data blocks: (1) The format which comes up prior to a full GPS solution, i.e., 3 or more satellites (as shown in Fig. 13B),
• RGHT means the direction of progression of pattern (left or right of the first swath [left is an option]) after first swath in a pattern.
• the LEFT/RIGHT key 70 toggles selection between
• BK-BK means the Pattern selected.
• the PATTRN key 80 toggles selection between options: Back-To-Back, Squeeze, Racetrack.
• WAIT-GPS means the system is waiting for a GPS solution, i.e., 3 or more satellites received. The GPS receiver uses corrections, last received, for up to one minute.
• OFF R 0000 means the distance, in feet, and direction to the centerline of the swath. Inoperative unless swath pattern is in progress.
• WD 000 00 means the data block for wind direction & speed
• TRK 000 means the true track of the aircraft in degrees.
• GPS display of the first format changes to "WAITING- A” which means a GPS solution and ready for pilot to initiate an A-B Line for parallel tracking 3and swathing. All other data blocks remain the same, except that values for WD, TRK and RG (if Home, Waypoint, or Return to Mark has been selected) will appear.
• the Navigation Screen 110 provides current position in latitude (LAT) and longitude (LON)
• Fig. 13C illustrates GPS received; otherwise, all values would be 0.
• W W SAT indicates a Waypoint which the pilot has defined and identified by the three letter identifier SAT, which is selected by WAYPOINT key 79. There are 10 waypoints in each of 12 routes.
• SP SP 120 indicates 120 mile-per-hour groundspeed. Valid only if GPS received.
• TK TK 317 indicates True Track over the ground of 317 degrees.
• BG BG 359 indicates True Bearing to selected Waypoint, Mark, or HOME in degrees.
• ALT ALT 00319 indicates height above a spheroid earth, (approximately mean sea level (MSL) in feet). If less than 4 satellites received, the system defaults to value entered in Program Screen.
• MSL mean sea level
• RG RG 0025 indicates distance in statute miles to selected Waypoint, HOME, or MARK. When the range is less than 0.19 miles (1000 feet) the display
• the GPS Satellite Screen provides information on time, date, satellites, degree of precision, GPS status, and bit test status.
• T GMT corrected by the time offset entered in the Program Screen hours, minutes, seconds. Available regardless of GPS solution status.
• D Current Date day, month, year. Available regardless of GPS solution status.
• MA Mask Angle, as entered in the Program Screen SV Mask Angle.
• DOP Dilution of Precision An index number which indicates the degree of accuracy of the current GPS solution. The lower the number, the better the accuracy. Generally, 4 or less will give very good tracking performance.
• DF Indicates time since last differential correction received. Normally O to 5.
• BT Indicates status of built-in-test (BIT) sequence, not significant to user if system operation properly. If other than OK, note code for technical debrief.
• PROGRAM SCREEN As seen in Fig.l3E the user presses the * key 71 to enter this screen from Swath, Navigation or GPS Satellite Screens. The user must press the Swath key 64 to exit this screen.
• the Program Screen 130 is for entering essential information for system operation.
• Swath Width 090 ft The Swath Width is the width in feet of the desired spray pattern and is operator selectable, depending on the chemical and type of aircraft/equipment.
• type in the number i.e., 70 for a seventy foot swath
• Screen/Enter key 77 To enter swath width, type in the number, i.e., 70 for a seventy foot swath, and then press Screen/Enter key 77 to accept the entry and scroll to the next item.
• Log Interval 02 sec The Log Interval determines the frequency of updates to the log file which is saved to the PCMCIA card 43. A setting of 99 disables the logging function.
• type in the number i.e., 02
• Screen/Enter key 77 To enter Log Interval, type in the number, i.e., 02, and then press Screen/Enter key 77 to accept the entry and scroll to the next item.
• Log Speed 50 mph The Log Speed is the speed, in statute miles per hour (ground speed) at which the system begins to log the flight path information. If track information from take-off to landing is required, set take-off ground speed or less. Otherwise, set lowest ground speed associated with the spray operation.
• ground speed the speed, in statute miles per hour (ground speed) at which the system begins to log the flight path information. If track information from take-off to landing is required, set take-off ground speed or less. Otherwise, set lowest ground speed associated with the spray operation.
• To enter Log Speed type in the number, i.e., 90, and then press Screen/Enter key 77 to accept the entry and scroll to the next item.
• the SV Mask Angle is the angle from the aircraft to a point in degrees above the horizon within which satellites are not used for positioning. This helps to reduce the probability that a key satellite will drop below the horizon during tracking operations. A setting of 5 is normal. In rugged terrain, with varying terrain, consider selecting a higher mask angle.
• Remote AB ON/OFF allows the pre-entered Waypoints, i.e.,
• Route 11 Waypoints 2 and 3 to pre-define an A-B line for a field prior to entry, given that the latitude and longitude for A and B are known.
• guidance is displayed to the field A-B line.
• To change the setting toggle the Up Arrow key 68 or the Down Arrow key 72 and then press Screen/Enter key
• SW# swath number
• Lightbar Angle 05 This setting is the angle in degrees preprogrammed for each light on the lower lightbar.
• a 5 degree setting would give values of 5 thru 75 degrees for lights 1 thru 15. (See Section 3g infra.). An entry of 99 will disable the lower lightbar, but the upper lightbar will still provide normal functions.
• To set the light value enter the desired numerical value and then press Screen/Enter key 77 to accept the entry and scroll to next item. The following is an example only. Individual settings for each light are pilot preference. Light # 01 0003 ft or 0002
• each option 1 thru 15 is a setting for a light pair, i.e. one left and one right of the center column of lights of the lightbar 46 (the swath centerline).
• Light #01 is the first light each side of center, and "0003" represents a
• Each light pair can be individually set to any value up to 9,999 feet based on user experience and preference. Another example is described with reference to Fig. 15, infra.
• Job The job name or number may be entered using up to 10 digits by toggling the up Arrow key 68 or the Down Arrow key 72 and the Screen/Enter key 77 between each digit.
• SAVE By selecting SAVE after each job the pilot starts a new file, which can be annotated by going to the Program Screen and changing the job number.
• pilot The pilot name or number may be entered using up to
• Aircraft 10 digits in the same manner as described above for the job number.
• the aircraft name or number may be entered using up to 10 digits in the same manner as described above for the job number.
• DGPS Format DCSA. Toggle between DCSA or RTCM, depending on Differential Correction System by toggling Up Arrow key 68 or Down Arrow key 72 and then press Screen/Enter key 77 to accept entry and scroll to next item.
• a Y/N option is provided. If "Y” is selected, the previous swathing pattern is automatically displayed if it had been "marked.” In order to allow a user to eliminate the swathing pattern, selecting “N” will allow multiple Mark key 69 /Return key 75 sequences, with Clear key 76 between each sequence, without recalling a previous pattern. This will allow unobstructed range, bearing, and guidance to any point "marked”. As a safety precaution, any previously "marked” pattern can be returned to by entering the Program Screen 130 and reselecting "Y” followed by the Return key 75 after re- entering the Swath Screen 100.
• the Waypoint Screen 140 is used to enter the ID and latitude and longitude of a Waypoint (field, airport, navigation fix, etc.). It is used in conjunction with the ROUTE key 78 and the WPT key 79 in order to select a specific route/waypoint for a new entry, or navigation based on a previously programmed position. Simply select the screen, select or enter a waypoint, then exit to the Navigation
• ROUTE 01 is 1 of 12 routes which can be selected by scrolling with the ROUTE key 78.
• WAYPT 03 is 1 of 10 waypoints available in each route, and is selected by scrolling with the WPT button 79.
• WAYP ID SAT is the three-letter, alphanumeric identifier for the Waypoint. Entry into the Waypoint Screen 100 during a swath pattern will not result in the swath being decreased and "frozen" at swath 1 upon exit from the Waypoint Screen.
• the AirStar lightbar 46 consists of 63 LED's arranged in two rows each with 15 red lights 153, 154 on the left and 15 green lights 151, 152 on the right. Three vertically arranged yellow lights 155 in the center are used to indicate when the aircraft is on track. The top row of 30 lights 151, 152 and bottom row of 30 lights 152, 154 are used to guide the pilot on track by indicating cross track error in feet and angular deviation in degrees from the desired spray line track.
• two banks of large 4 digit 7 segment numerical displays 156(right), 157(left) one on each side of the two rows of LED's are programmed to display various information to the pilot (e.g., swath number). Brightness is controlled by the keypad rheostat 54.
• the lightbar of the present invention significantly enhances readability of the lightbar lights and symbols which is most noticeable in high ambient light conditions.
• Lightbar 46 uses a conventional circular polarizing material from Polaroid as the display window 158.
• the material is constructed from a linear polarizer that is laminated to a 1/4 wave optical retarder plate 158a. The use of this material allows ambient light to enter the lightbar 46 display area, but does not allow odd order reflections (most of the reflected or back scattered light) to escape.
• the circular polarizing window 158, 158a is combined with a mounting configuration that further enhances the display performance.
• the display window 158, 158a is mounted at an angle to the shaded interior roof 159 of the lightbar shroud which provides as the first surface reflection, a reflection of the dark roof 159 of the lightbar shroud which is not visible. The effect is so good that users reach out to touch the display window 158,
• the lights 151, 152, 153, 154 have the following meanings:
• the Lightbar 46 is a single unit designed to be internally or externally mounted.
• the pilot can see the lightbars with just his peripheral vision. It provides information to the pilot for tracking, guidance, angle-off-swath, rate of closure on or departure from swath, swath #, and distance off-swath by means of the two independent, horizontal rows of lights 151,153,152,154 and the two digital readouts 156,157 located at each end of the lightbar.
• the left digital window 157 provides distance in-feet left or right of the aircraft to the swath centerline. Thus, to get to the swath centerline, the pilot must always "fly into the lights".
• L032 in display 157 of Fig. 14A tells the pilot that a correction left 32 feet to centerline is required.
• a read-out of R166 for example, tells the pilot that a correction to the right of 166 feet is required.
• the right digital window 156 provides two options: 1. Angle to or away from the swath.
• the - 030 in the right display 156 means an intercept angle of 30 degrees toward the swath centerline is established. The minus will change to plus if, for example, an aircraft right of the swath centerline turns away from the swath.
• the illustration in Fig. 14B shows how the angle window will change relative to the aircraft's approach toward or departure from the swath centerline. 2. 0020 the current swath number. The pilot selects this option in the Program
• the upper row of lights 151,153 provides distance in feet to the swath centerline, rate of drift toward or away from centerline, and direction left or right to the centerline.
• Each light-pair, i.e., #1 left and right through #15 left and right is programmable in the Program Screen 130 to indicate a specified number of feet off track, e.g., 3 feet or 5 feet, depending on user preference.
• a single GREEN light 151 would mean, left of centerline by 3 feet, turn right. If the vertical row of yellow lights 155 are lit, it means on track, steady as you go. Three redlights 153 means 9 feet right, turn left to correct. In a normal operating mode the AirStar system updates the lightbar five times per second. Rate of approach toward, or away from, the swath centerline can be judged by the rate at which the lights 151, 153 are being extinguished, or illuminated, respectively (the rate is a function of the intercept angle, ground speed, and displacement value assigned to each light). The center column of yellow lights 155 represents swath centerline when a pattern has been initiated.
• the lower row of lights displays the difference (angle, in degrees) between the aircraft's track over the ground and the track of the current swath. It is programmed in the Program Screen. For example, as seen in Fig. 14D, an aircraft tracking 330 degrees true and approaching from the right a swath with a true course of 360 degrees, represents an intercept angle of 30 degrees, which will be reduced to O degrees as the aircraft intercepts and parallels to align with the swath.
• the system allows entry of a single value, i.e., 4 or 5 or 6.... etc., for each lower light 152, 154 each one of which will be scaled in degrees by the selected increment to provide an increasing incremented series i.e., 4, 8, 12, or 5, 10, 20, or 6, 12, 18 etc.
• the system may also be programmed to allow for individually programmable lights, as in the upper row of lights 151, 153. Variable degree settings may be programmed into the lower lightbar to the tenth of a degree. This feature gives faster response to angle deviations when on-track during swathing.
• the lightbar 46 example in Fig. 14D represents the picture illustrated above the lightbar:
• the L030 in the left data window 157 means the swath centerline is 30 feet to the left.
• the 030 in the right data window 156 means a left angle of intercept of 30 degrees closing toward the swath centerline.
• the lower row of lights 154 the #5 green light illuminated @ 6 degrees per light, indicates an angle of intercept of 30 degrees.
• the pilot based on the decrease in distance, and rate of decrease, will decrease the intercept angle, which will be also indicated by the lit lower light # also decreasing toward the centerline.
• a greater intercept angle may be desired.
• the pilot would turn further left (indicated by the lit lower light # 154 moving further left as the intercept angle increases). Because of this turn to cross the swath and close the distance to the swath more rapidly (increase the correction), the lit number of upper lights will begin to decrease more rapidly and will require the pilot to use a steeper angle of bank tiirning toward the swath true course (take out the correction) as centerline is approached. See Figs. 14E-14F.
• the table in Fig. 15 relates the Angle-Of-Intercept to the Off-Track position.
• the pilot will vary angle-of-bank so as to keep the lit lower light 152,154 (angle) exactly beneath the outboard lit upper light 151, 153.
• the pilot would steepen the angle-of-bank turning toward the swath true course to reduce the intercept angle (bring the lower light closer to and beneath the outboard lit upper light).
• the intercept angle is too small, the lit lower light will be inboard of the outboard lit upper light and the pilot will need to shallow the angle-of-bank to allow the outboard lit upper light to decrease and drift in to a point above the lit lower light until they are vertically in line with each other. Then the pilot should reestablish the steeper bank turning toward the swath true course needed to keep the vertically aligned lit lights moving in toward the center column of amber light 4 together. (See Figs. 14E 14F).
• Fig. 14E The example shown in Fig. 14E is from the table in Fig.15 with values from the
• Light & Tight column 40 degrees intercept angle and displacement of 309 feet. Should the aircraft overshoot, the upper lights will shift to the right (red to green) and increase until the aircraft turns through a track parallel to the swath.
• Fig. 16 shows a conventional flow controller system 160 currently widely, used in applying a materials using an agricultural ("AG") airplane.
• AG agricultural
• these materials are pesticides, herbicides, seed, fertilizer and bait, all of which may be in liquid or dry form.
• the pump may be either an electrical, hydraulic or wind-driven pump.
• the shut off valve 162 With the shut off valve 162 in the off position, the chemical inside the tank 163 is pumped through the shut off valve 162 and the recirculation line 164 back to the tank. This action pressurizes the system in preparation for spraying.
• the pilot is over the point in which application is needed, he manually repositions the shut-off valve 162 to the on position by an amount based on past experience needed to meter the desired flow
• the pilot While flying the pass, the pilot monitors air speed 165 and flow readout 166 measured by the flow meter 167. When the flow readout 166 varies from the desired value, the pilot manually adjusts the control valve 162 to maintain the proper flow rate to the nozzles 168. The pilot must manually adjust for wind direction and speed. At the end of the last pass over the application area, the pilot manually turns the shut-off valve 162 to the OFF position.
• Fig. 17 shows the improved flow controller system 170 of the present invention which reduces pilot workload and maintains a high degree of accuracy and accountability of application of the material.
• a flow controller module 171 automatically and continuously monitors actual ground speed and true position over the earth provided by the differential global positioning system.
• the precise position provided by DGPS allows for precise application of the chemical to the desired area. Variations in ground speed are quickly, accurately and automatically adjusted.
• the pilot's interaction is reduced to simply monitoring when to begin and stop spraying and monitoring the actual flow rate desired, i.e., the gallons of chemical dispensed per acre, per linear distance, or per minute.
• the flow controller 171 does the rest of the work.
• the system monitors and delivers application material volume as a function of time as demanded in real time by the host system.
• Shown in Fig. 17 is one embodiment of the invention, wherein a flow control module 171 is a stand alone enclosure housing a digital microprocessor or
• microcontroller which controls integral units which include shut off valve 175, flow
• component parameters infrequently changed, mission specific parameters, and material specific parameters, which affect flow, such as, flow rate in volume/time or volume/distance or volume/area, swath width, spray boom width, desired ground speed, starting payload and viscosity.
• the flow controller 172 automatically turns on the pump 173 to pressurize the system causing the chemical to be recirculated 174 through the shut-off valve 175 back to the tank 176 with flow control valve 180 off.
• the pilot 177 presses the spray on switch (not shown). This command is received 178, 179 by the flow controller 172 which opens the flow control valve 180.
• the flow controller 172 continuously monitors the flow meter 181 and maintains the rate preselected by the pilot 177, 178, 179 by making automatic adjustments to the flow control valve 180 to compensate for any deviations which would alter the actual ground speed and track over the ground as reflected by the DGPS 182.
• the pilot 177 presses the spray off switch which command is received 178, 179 by the flow controller 172 which then shuts off valve 180. On the next pass the cycle is repeated. Information such as actual flow rate, amount of chemical remaining in the tank
• amount of chemical used, wind, speed or stuck valve may be displayed to the pilot
• the present invention uniformally applies a prescribed amount of agricultural product, liquid or solid, by unit area and measures the rate at which the product is dispensed in real time and logs and displays the results. For certain solid materials the
• flow control valve 180 and flow meter 181 are replaced with a positive displacement pump that is demanded by the controller to deliver a specific volume of material as a function of time. Real time tracking of the remaining pay load and the total material applied is also provided.
• the system automates the initiation of chemical application based on the location of the application vehicle and a preprogrammed spray area.
• the flow controller 172 of the present invention may be used, as shown above, with a host system such as the DGPS 182, that provides accurate ground position/speed information.
• the host system 182 provides a user interface 179 to the flow controller 172.
• the flow controller 172 may be incorporated as an actual part of the host system 182 as a single component.
• a host system 182 is the AirStar DGPS Swath Guidance System with dual row lightbar described in the present application and manufactured by SATLOC, Inc. of Casa Grande, Arizona. This host system, when connected to control the flow controller system 170 described above, is described as providing "Spray Sentry" 170 capability.
• the host system may provide the equipment operator functionality that is equal to or considerably beyond that required to support the flow controller 172 alone.
• a simplified system would integrate the position, speed sensing and demand generation functions into the flow control module.
• Fig. 17 The embodiment disclosed in Fig. 17 is the present preferred mode.
• the system may comprise separate flow control module, flow monitor module, and proportioning module to carry out these separate
• the flow controller 172 shown in Fig. 17 may be separate from the shut off valve, flow control valve and flow meter, the latter three being each separate units.
• sequence of events for dispensing may be controlled in another
• shut off valve 175 With a constantly driven pump 173, the pilot approaches the area to be sprayed with shut off valve 175 off. Based on GPS supplied ground speed 182 flow controller 172 prepositions flow control valve 180 to a "best guess" opening. As the pilot 177 reaches the point of begin application, he manually opens shut off valve 175, as shown by the dotted line 177a in Fig. 17, causing material to flow through flow control valve 180 and flow meter 181 to the nozzles 168. The pilot's opening of the shut off valve 175 is sensed by the flow controller 172 via a limit switch (not shown).
• the flow controller 172 continuously monitors flow meter 181 and maintains the rate preselected by the pilot 177, 178, 179 by making automatic adjustments to the flow control valve 180 to compensate for any deviations which would alter the actual ground speed and track over the ground as reflected by the DGPS 182.
• the pilot 177 manually closes the shut off valve 175 which
• shut off valve 175 and the flow control valve 180 may be integrated into a single valve (not shown) wherein
• the on-off and metering functions are manually or electronically controlled or both or some combination thereof.
• a pressure sensor 175a monitored by the flow controller 172 can greatly augment the status and dynamic response of the control loop by largely reducing gain modulation of the control loop due to shut off valve position and pump pressure variations.
• the Spray Sentry 170 settings are displayed by the VIEW Button 62 on keypad 60. Press SWATH key 64 to exit. These keys are not functional unless the Spray Sentry 170 feature is installed in the AirStar system. To select Acres Per Pass, press 5 VIEW key 62, scroll to Acres/Pass Y/N, and toggle "Y". Cumulative acres will be tabulated, based on swath width and ground speed, when the PLOT button 66 ia pressed or spray is actuated. To display the result in the left or right digital window on the lightbar 46, select A/P as the programmable lightbar 46 option described earlier. Examples of applications of the Spray Sentry 170 feature range from crop dusting to spraying oil dispersant over oil-laden waters. The efficiency of Spray Sentry 170 optimizing spray application and minimizing excess application results in a typical savings of 35% of chemical cost alone.
• the computer 41 loads 202 its software and performs a built-in test sequence
• the pilot selects the Programming Screen to CHECK set-up by scrolling the entire menu to be sure all settings are correct.
• the pilot sets Swath Width, 207 (default 208 is 75 feet), Log Interval, Log Speed MPH, Mask Angle 5, and the Lightbar.
• display box 45 left green lite 91 is ON, all red lights 92, 93 are OFF, the
• SAVE/PURGE key 74 is depressed to CHECK MINUTES REMAINING on memory card 43 and, finally, the system is Ready to Spray.
• the pilot can perform a confidence check on the system.
• the pilot sets up the A-B line on a known straight line such as the centerline of the runway. He then flies several swath advances, and then, decreases the swath back to #1. He lines up on the runway centerline and notes that the lightbar centers up, right down the swath centerline. He flies this numerous times until he gets the feel for making smooth corrections, and, just as importantly, has the confidence that the system flies straight.
• the computer is determining 209 whether a grid has been laid out.
• the pilot flies 210 the A-B/C lines to set up the grid.
• the program steps to determine 211 the latest position from the GPS receiver and compares 212 the current aircraft position with the desired position as predicted by the grid.
• the computer next determines the lateral position of the aircraft relative to the selected swath track the pilot desires to fly.
• the results of this evaluation will control the driving of the upper bar lights 151, 153 and the left hand digital display 157 in lightbar 46. Having determined 214 how far left or right the aircraft is, the result is converted 215 to lighting a prescribed number of LED'S using the variables as set by the pilot in the menu. If the aircraft is left of desired track by an amount greater than X, the system drives 216 the prescribed number of green lights 151 on the upper lightbar. It also drives 220 the left hand digital display 157 showing the off track error in feet. If the aircraft is off track by an amount greater than X to the right of the desired track, the system drives
• the system drives 219 the amber light 155 at the center of the upper light bar
• the system determines the intercept angle being flown by the aircraft relative
• the system drives 225 the amber light 155 in the center of the lower lightbar. If the track angle is more than the value set by the pilot, the system divides 226 the amount of the track angle by the variable V to obtain a quotient.
• the system determines 227 whether the current track will reduce the off track position error. If it does, the system will illuminate 229 the appropriate # LED on the lower lightbar equal to the quotient distance from the center LED on the side of the lightbar opposite the side of the swath line on which the aircraft is actually located. If the current track will not reduce the off track position error, the system will light 228 the appropriate # LED on the lower lightbar equal to the quotient distance from the center
• the system returns 230 to obtain 211 the latest position from the GPS receiver, and repeats the cycle all over again.

Landscapes

• Engineering & Computer Science (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Computer Networks & Wireless Communication (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Position Fixing By Use Of Radio Waves (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=22586020

Family Applications (1)

Country Status (4)

Families Citing this family (17)

Family Cites Families (7)

• 1994
  • 1994-12-02 WO PCT/US1994/013845 patent/WO1995015499A1/en not_active Application Discontinuation
  • 1994-12-02 EP EP95909197A patent/EP0742907A1/de not_active Withdrawn
  • 1994-12-02 BR BR9408245A patent/BR9408245A/pt not_active Application Discontinuation
  • 1994-12-02 AU AU17243/95A patent/AU1724395A/en not_active Abandoned
• 1996
  • 1996-06-28 AU AU56236/96A patent/AU5623696A/en not_active Abandoned

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events