Abstract:
Methods and systems for programming the automatic guidance unit of an aerial delivery system. The operator selects on a hand-held unit the desired flight parameters such as the latitude, longitude and altitude of the desired landing site, as well as the desired landing heading and default heading. A microprocessor converts this data into digital data that is stored on a removable EEPROM memory key. This key is then removed from the hand-held unit and at any convenient time, inserted into a mating female receptacle in the automatic guidance unit of the aerial delivery system. The programmed information originally entered in the hand-held unit is then transferred into the guidance unit of the aerial delivery system.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/226,423 filed Aug. 18, 2000 entitled “Automatic Guidance Unit For Aerial Delivery Unit.” 
    
    
     FIELD OF THE INVENTION 
     This invention relates to automatically controlled aerial delivery systems and methods and apparatus for programming the automatic guidance unit of such aerial delivery systems. 
     BACKGROUND OF THE INVENTION 
     Automatically guided ram air parafoil parachutes are excellent vehicles for delivery of cargoes from airplanes in situations when weather, terrain or military conflict makes aircraft landing difficult or impossible. One such airborne parafoil vehicle is the PEGASUS Advanced Precision Delivery System (APADS) available from FXC Corporation, the assignee of the present invention. 
     SUMMARY OF THE INVENTION 
     Prior to deploying a guided parachute system from an airplane, the on-board guidance system is preprogrammed with the target information. Heretofore, the complexity and difficulty of programming this on-board guidance system has greatly inhibited the use of automatically guided parafoil canopies or parachutes. Even though the ram air parafoil is capable of very accurately reaching targets from 30,000 feet aloft and several miles away from the target location, even a small error in preprogramming the airborne guidance system can completely negate the mission by causing the delivery system to land miles away from the targeted location. 
     The preferred embodiments of the present invention employ a simple handheld programming unit into which the coordinates and other parameters of the target location are set by simple thumbwheel switches. This programming can be quickly and accurately performed in the field by someone completely lacking in computer training or computer skills. 
     The preferred embodiments of the hand-held programming unit include a key receptacle accessible from outside of the unit. This receptacle accepts a key having an integral EEPROM or other data memory, which when inserted into this receptacle is loaded with the target location data that the user has manually entered into the handheld unit using the thumbwheel switches. 
     The memory key, now loaded with the target information, is easily carried by a responsible person for arming the guidance system. At the appropriate time before deployment of the load, this memory key is inserted into a mating receptacle located on the airborne guidance unit. The airborne unit is then immediately armed with the geographic coordinates and other data necessary for preprogramming the onboard flight guidance computer. 
     A significant feature of the programming system and procedure is its ease of use and minimal training requirements. No step requires the user to be trained in computers or the use of any computer operating or application software. As a result, the opportunity for making mistakes in the field is greatly decreased. Moreover, preloading the program data is very simple and straight forward and can be easily and quickly performed whether the parachute and guidance system are still on the ground waiting to be loaded into the airplane or after the unit has been loaded within the airplane. In addition, the programming of the memory key can be performed at any convenient time and by a different person than the personnel involved in deploying the guided parachute from the airplane. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1A and 1B show a cargo carrying ram air parafoil canopy in flight after it has been deployed from an airplane; 
     FIG. 2 shows the ram air parafoil canopy with an automatic guidance unit as it is packed before loading onto an airplane; 
     FIG. 3A shows a programmable memory key for programming the automatic guidance unit; 
     FIG. 3B shows the female receptacle used in the automatic guidance unit and the hand-held programmer unit for receiving the programmable memory key; 
     FIG. 4A shows a top plan view of one embodiment of the automatic guidance unit; 
     FIG. 4B shows a top plan view of a modified servomotor-pulley arrangement; 
     FIG. 4C shows a top plan view of another embodiment of the automatic guidance unit; 
     FIG. 4D shows a side elevational view of the automatic guidance unit of FIG. 4 c;    
     FIG. 5 is a perspective view of one embodiment of a hand-held programming unit; 
     FIG. 6 is a top view of the unit of FIG. 5; 
     FIG. 7 is a block diagram of the hand-held programmer of FIGS. 5 and 6; 
     FIG. 8 is a top view of another embodiment of the hand-held programming unit; 
     FIG. 9 is a block diagram of the hand-held programmer of FIG. 8; and 
     FIGS. 10 a  and  10   b  show exemplary circuitry for the hand-held programming unit. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Exemplary ram air parafoil canopy  20  and  20 ′ are illustrated in FIGS. 1A and 1B. Such parafoil canopies are used to deliver payloads from airplanes flying at high altitudes. Canopies manufactured by FXC Corporation, assignee of the present invention, have glide ratios in excess of 4.5:1. Reefed deployment allows these ram air parafoil canopies to be dropped at speeds up to 200 knots indicated airspeed (KIAS) from altitudes of 30,000 feet mean sea level (MSL) with reliability. Typically, canopy  20 ,  20 ′ includes a plurality of suspension lines attached directly to the canopy and then extending downwardly and inwardly. Suspended from the suspension lines are a restraining device  34  for controlling the rate of inflation of the canopy  20 ,  20 ′ and the airborne guidance unit (AGU)  30  to control the flight path to the canopy  20 ,  20 ′. The embodiment shown in FIG. 1A also shows the parachute bag  32 , whereas in the embodiment of FIG. 1B, this bag is retained proximate to the underside of canopy  20 ′ and is therefore not visible in FIG.  1 B. Right and left risers are controlled by servomotors located within the AGU  30 . The load  36  is carried below the AGU  30 . 
     The airborne elements of FIGS. 1A and 1B including the parafoil canopy  20 ,  20 ′ and AGU  30  within a case  44  are shown in FIG. 2 in their packed state before being deployed from an airplane. 
     The preferred embodiments of the AGU include servo controls for rotating two pulleys respectively coupled by gear trains to stepper motors. In one embodiment of the AGU unit  30  shown in FIG.  4 (A), the right and left risers are respectively attached to control lines wound around pulleys  50  and  52 . Respective stepper motors  54  and  56  are coupled through respective gear boxes  58  and  60  to drive pulleys  50 ,  52 . FIG. 4B illustrates an alternative embodiment in which the pulleys  50 ′ and  52 ′ are shown in cross-section with pulleys  50 ′,  52 ′ stepper motors  54 ′,  56 ′ and gear boxes  58 ′,  60 ′ disposed in line along a common axis. 
     Another preferred embodiment of the airborne guidance unit (AGU)  30 ″ is shown in FIGS. 4C and 4D. Stepper servomotors  54 ″ and  56 ″ are connected to respective pulleys  50 ″,  52 ″ around which are wound the lines controlling the parafoil canopy. Power is supplied to the onboard control circuitry and servomotor by a battery  57 ″. Typically, this battery is a 12-volt battery. The onboard control circuitry is mounted on a circuit board  59 ″. An onboard transceiver  61 ″ and antenna  63 ″ provides a wireless datalink to ground. GPS receiver  60  supplies latitude, longitude and altitude information to the onboard AGU digital flight computer. 
     By way of one specific example, approximately 30 inches of control line is wrapped around each of the pulleys  50 ,  52 , the gear boxes have an 18 to 1 ratio and the servo actuator stepper motors  54 ,  56  are driven at a 5,000 Hz rate so that the control lines are moved in and out from the pulleys  50 ,  52  at approximately one foot of control line per second. 
     The AGU&#39;s  30 ,  30 ′ and  30 ″ advantageously include a digital flight computer (typically several microprocessors and associated memory), a GPS receiver  60 , an altitude sensor, a compass, a power supply and batteries. An air speed sensor can also be included. The digital flight computer processes information from the GPS receiver  60  and other airborne sensors to determine the trajectory to intercept and land the canopy  20  while conserving altitude and compensating for wind variations. On example of a flight computer program is that utilized in the PEGASUS APADS aerial delivery system manufactured by FXC Corporation, assignee of the present invention. 
     Prior to deployment of the parafoil  20  and its load  36  from the airplane, the digital flight computer must be preprogrammed. Typically data input includes the geographical coordinates of the desired landing location, the anticipated landing heading, the altitude of the landing site and the barometric pressure. As described below, significant feature of this invention is that the AGU&#39;s  30 ,  30 ′ and  30 ″ are very simply and easily pre-programmed before deployment by entering a memory key  40  (shown in FIG. 3) into a mating female receptacle  42  accessible at the outside of the case  44  which contains the AGU. 
     The preferred embodiments of this invention provide a hand-held programming unit. Preferred embodiments  70  and  170  of this hand-held unit are shown in FIGS. 5,  6 ,  7 ,  8 , and  9 . In the embodiments of FIGS. 5,  6 , and  7 , the latitude, longitude, landing altitude, barometric pressure, landing heading and default heading information relating to the desired landing location is entered by respective thumbwheel switches  72 ,  74 ,  76 ,  78 ,  80  and  82  or like devices into a microcomputer  84  located within the handheld unit. 
     In the hand-held unit  170  shown in FIGS. 8 and 9, the thumbwheel switch for entering barometric pressure is not required since accurate altitude information is provided by the global positioning system (GPS)  60  onboard the AGU. Therefore, unit  170  includes respective thumbwheel switches  72 ,  74 ,  76 ,  80 , and  82  or the like, respectively entering the latitude, longitude, landing altitude, landing heading, and default heading information relating to the desired landing location. In addition, AGU unit  170  advantageously includes a code selector switch  183  for encoding the programmable key  40  with a particular code number recognizable by the AGU. These manually entered values are supplied as inputs to the microprocessor computer  84 . Key  40  is inserted into receptacle  142  and the data stored in the computer  84  is read into the EEPROM memory located within key  40 . LED readants  201 ,  202  indicate that the data has been stored in key  40 . 
     Exemplary internal circuitry of the hand-held unit  70  and  170  is illustrated in FIGS. 10 a  and  10   b . Thumbwheel switches  80  and  82  are shown in FIG. 10 a  and thumbwheel switches  72 ,  74 ,  76 , and  78  are shown in FIG. 10 b . FIG. 10 a  further illustrates code switch  183  of AGU  170 . It will be understood that since the barometer switch  78  is eliminated in the AGU  170 , the switch  78  and its associated diode array shown in FIG. 10 b  need not be included in AGU  170 . 
     Buses connect each switch directly to microprocessor  84  or via decoder  198 . Computer  84  addresses each switch and enters the data into the programmable key inserted into receptacle  42 . Also shown in the schematic of FIG. 10 a  are a 5-watt regulating power supply  200  and LED readants  201 ,  202 . 
     Advantageously, key  40  is a flash EEPROM memory key such as those described in U.S. Pat. No. 4,578,573 and available from Datakey, Inc., Burnsville, Mich. 55337 (www.datakey.com). Key receptacles  42  in the handheld unit  70  and key receptacle  142  in the hand-held unit  170  accept the key  40  and transfers the data inputted into the memory within the microcomputer  84  into the EEPROM memory located within the key  40 . 
     At any convenient time, before or during flight the key  40  is inserted into a mating receptacle  42  on the AGU case  44  (See FIGS. 2 and 4 d ) to arm the AGU. Turning the key  40  in receptacle  42  causes the data stored on key  40  to be read into the memory of the microprocessor within the AGU  30 . An indicator lamp  46  is then caused to intermittently flash indicating that the memory data has been transferred from key  40  and stored in the AGU  30 . 
     The handheld data entry units  70 ,  170  and key  40  are significant improvements in perfecting load carrying parafoil canopies. Heretofore, the flight data was programmed on a lap top computer and required the user to be knowledgeable in the use of a computer keyboard and using computer application and operating software such as, for example, the MS-DOS or Window computer operating systems. Mistakes in entry of data often resulted in the cargo never reaching its desired target. In warfare or disaster situations, such errors can be catastrophic since the cargo either may not reach the target area or fall into the hands of the enemy forces. In the field, repeated tests have proven that the use of a programmed laptop computer to preprogram the onboard AGU is not satisfactory. In contrast, the handheld unit  70  is easily and simply mastered and requires no computer knowledge or skills. 
     The preferred embodiments of the present invention include a power switch which limits the power drawn from the ACG battery until the canopy ACG and load pack shown in FIG. 2 are deployed form the airplane. Advantageously, the receptacle  42  and indicator lamp  46  and battery charger plug (not shown) are available for use without having to power up the servo amplifiers, servo motors and ACG sensors until the AGU is deployed from the airplane. At such time, the on-board ACG battery is connected to drive the flight control servos and control lines  26 ,  28 , as described above. 
     Appendix A is a publication of FXC Corporation entitled “PEGASUS-500 APADS SYSTEM DESCRIPTION.” Appendix B is a copy of a publication of the American Institute for Aeronautics and Astronautics entitled “Development of A High Glide, Autonomous Aerial Delivery System ‘Pegasus 500 
     (APADS)’.” Appendices A and B provide additional information about actual embodiments of the invention including test data from actual flight testing of these embodiments. 
     While the invention has been described herein with reference to certain preferred embodiments, these embodiments have been presented by way of example only, and not to limit the scope of the invention. Accordingly, the scope of the invention should be defined only in accordance with the claims that follow.