Abstract:
A retrofit digital electronics unit replaces the analog electronics unit of a tube-launched optically-tracked wire-guided missile. The retrofit digital electronics unit is smaller in size permitting the warhead of the missile to be enlarged. Additionally, the retrofit digital electronics unit is more susceptible to modification through simple changes in software.

Description:
RELATED INVENTIONS 
     Applicant acknowledges copending application Ser. No. 07/384,228 filed Jul. 21, 1989 and assigned to the same assignee as the present invention. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention: 
     This invention relates generally to the tube-launched optically-tracked wire-guided family of missiles and more specifically to a retrofit electronics unit therefore. 
     2. Description of Related Art: 
     These types of missiles were first developed over a decade ago and have proven themselves as very effective weapon against such targets as tanks, personnel carriers, bunkers, and the like. 
     A large part of these missile&#39;s effectiveness and appeal is its simple operational concept. The operator of the missile &#34;guides&#34; the missile to the target. Communication with the missile is through a wire or fiber optic link. Using a telescope and cross hairs arrangement, the operator controls the line of sight flight path of the missile to avoid field obstructions such as trees or hills. Since the operator controls the line of flight, a great operational burden is removed from the missile; it doesn&#39;t require the high level of electronic &#34;brains&#34; or complexity of other missiles. This reduces the cost of the missile significantly. 
     These operator generated signals are communicated in analog form utilizing changes in frequency in the communication link (a pair of thin steel wires). Because the incoming signal is analog, the electronics unit is also analog which makes the electronics unit bulky and complex. 
     One major disadvantage associated with analog circuits, is that even simple modification of the circuit&#39;s objective or operation is extremely difficult, requiring almost a total re-engineering of the circuit. This prevents the engineers from &#34;fine tuning&#34; the electronics unit. 
     The electronics unit is the &#34;brains&#34; of these missiles and implements the commands of the operator by adjusting the pitch and yaw control surfaces. These control surfaces guide the missile. 
     The various components making the missile (i.e. the warhead, the electronics unit, the flight motor, the launch motor, etc.) are unique separate modules permitting the missile to not only be easily maintained, but also component upgraded without undue re-engineering of the entire system. 
     The electronics unit is typically positioned directly behind the warhead in a forward position on the missile. The presence of the bulky electronics directly behind the warhead unit limits the volume available for the warhead. For some applications or targets, the limited size of the warhead is a disadvantage. 
     It is clear from the forgoing that the present analog electronics unit creates many engineering problems which hinders the ready upgrade of the tube-launched missiles. 
     SUMMARY OF THE INVENTION 
     The present invention replaces the purely analog electronics unit of the tube-launched missile with a hybrid analog/digital electronics unit. 
     The replacement electronics unit attaches to the existing wire harness and fits into the cavity created by removal of the traditional electronics unit. This hybrid electronics unit permits not only easy modification (through software changes to the digital micro-controller) but reduces the size of the electronics unit to such an extent that the size of the warhead can be significantly increased providing a more powerful and effective missile. 
     The hybrid electronics unit of the present invention utilizes the analog signals from the operator together with the missile&#39;s own internal positional signals generated by the yaw and roll gyros to manipulate the yaw and pitch control surfaces. 
     All signals received by the replacement electronics unit and sent out by it, are communicated through the traditional wire harness. This characteristic eliminates any undue modification to the missile and permits the missile to be easily retrofitted with the replacement electronics unit. 
     Any subsequent engineering changes to the electronic &#34;brains&#34; are easily accomplished by simply modifying the internal software of the digital microprocessor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a functional block diagram of the preferred embodiment. 
     FIG. 2 is an electronic schematic of the positional status determination mechanism first described in FIG. 1. 
     FIG. 3 is an electronic schematic of the decoding circuit for the operator generated signal first described in FIG. 1. 
     FIG. 4 is a wiring diagram of the micro-controller first described in FIG. 1. 
     FIG. 5 is an electronic schematic illustrating the handling of the signal used to control pitch and yaw. 
     FIG. 6 is an electronic schematic illustrating the handling of the signal used to control pitch and yaw and completing the objectives of the circuitry of FIG. 5. 
     FIG. 7 is a cut-away view of an embodiment of the invention when implemented into a missile and a missile system. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates, in block form, the operation of the preferred embodiment of this invention. At the center of the operation is the micro-controller 12. Utilizing it&#39;s software, the micro-controller 12 is the &#34;brains&#34; of the operation. 
     In this capacity, the micro-controller must be cognizant of the missile&#39;s positional status. This information is derived by utilizing the signals from roll gyro 17 and the yaw gyro 18 received from the wire harness (not shown). 
     The positional status mechanism 10 utilizes these signals for the generation of the roll signal and the yaw signal which are used by the micro-controller 12. By taking the signal from the roll gyro 17 and converting it via converter 10a into the roll signal, and taking the signal from the yaw gyro 18 and converting it via converter 10b into the yaw signal, the proper information is available to the micro-controller 12. 
     Information as to the operator&#39;s instructions/directions are communicated to the micro-controller 12 via the directional mechanism 11. 
     The operator feeds in the desired directions into operator interface 16. This directional information is communicated via a communication link (not shown) to the directional mechanism 11. The communication link used for these missiles is a continuous physical link (i.e. steel wire, copper wire, fiber optics, or the like) between the operator interface 16 and the missile. 
     In this regard, directions from the operator are translated by the launcher into the proper signals indicating if the missile is on track or not. For purposes of this description, the operator generated signals are these translated signals. 
     Since the communication link is a single pair of wires, the analog signal from the operator must be broken into its component parts by the directional mechanism 11. This is done by taking the incoming signal and passing it through a carrier separation filter 11a which generates the pitch signal and the yaw signal used by the micro-controller 12. 
     A low pass filter with negative threshold 11b obtains the yaw stabilization signal. 
     Utilizing this information from the status mechanism 10 (roll signal and yaw signal), and the directional mechanism 11 (pitch signal, yaw signal, and yaw stabilization signal), the micro-controller 12 is capable of manipulating the missile through signals sent to the manipulation mechanism 13. 
     Manipulation mechanism 13 amplifies the signals from the micro-controller 12 and communicates the amplified signals to the proper actuators. In the preferred embodiment, the actuators manipulate the control surfaces to affect the pitch and yaw of the missile in flight through the release of pressurized helium. 
     Operationally, micro-controller 12 communicates four signals which pass through: Power Driver 13a to generate the Yaw 1 Actuator Signal manipulating Actuator 19a; Power Driver 13b to generate the Pitch 2 Actuator Signal manipulating Actuator 19b; Power Driver 13c to generate the Yaw 3 Actuator Signal manipulating Actuator 19c; Power Driver 13d to generate the Pitch 4 Actuator Signal manipulating Actuator 19d. These power drivers are simply the preferred mechanism as means for amplifying the signals. 
     In this manner, the objectives of the operator are quickly and easily translated into their proper sequence of missile manipulations. 
     FIG. 2 is an electronic schematic of the preferred embodiment of the status mechanism first described relative to FIG. 1. 
     Signals from the roll gyro 17 and the yaw gyro 18 are communicated to the positional status mechanism 10. Those of ordinary skill in the art readily recognize various gyros which may be used in this context. 
     Signals from the yaw gyro 17 and the roll gyro 18 are communicated to the status mechanism 10 via connector 27. The yaw gyro signal-A 23, the yaw gyro signal-B 24, the roll gyro signal-A 25, and the roll gyro signal-B 26, are manipulated and a yaw gyro signal 21 and roll gyro signal 22 are communicated to the micro-controller 12. 
     FIG. 3 illustrates the preferred embodiment of the circuit used to create the directional mechanism 11 which accepts the signals indicative of the operator&#39;s directions via the operator interface 16 (shown in FIG. 1). 
     The wire signals from the operator interface 16 are handled by two substantially independent circuits to establish the pitch signal 31 and the yaw signal 32. Control signals 33 and 34 are also communicated to the micro-controller 12. 
     FIG. 4 illustrates the use of the signals from the positional status mechanism 10 and the directional mechanism 11 by the micro-controller 12. The yaw gyro signal 21 and the roll gyro signal 22 (as illustrated in FIG. 2), pitch signal 31, yaw signal 32, and yaw shorting signal 34 (as illustrated in FIG. 3) are combined within the micro-controller 12 to generate the control signals 41a, 41b, 41c, 41d, and 41e; also generated is control signal 42. 
     In this manner, the positional status of the missile is combined with the directions from the operator for proper manipulation of the missile in flight. 
     Through software, micro-controller 12 determines when a &#34;first motion&#34; occurs. Launch of the missile determines when micro-controller 12 can manipulate the missile&#39;s flight. First motion is determined by observing the pitch control signal from the launcher. Those of ordinary skill in the art recognize several embodiments that accomplish this task. 
     In the preferred embodiment, the micro-controller 12 is a microprocessor, part number 8797 BH, commercially available from Intel Corporation. Stored within the micro-controller 12 is the software designed to manipulate the incoming signals and perform the correct function. The preferred embodiment for this software is illustrated in the following Table A and is written in Macro Assembly for the Intel 8797 BH. ##SPC1## 
     FIG. 5 illustrates the preferred embodiment of the circuitry used to take the control signal 42 (originally described in FIG. 4), and generate the various balance signals. This includes the pitch balance-A 50a, pitch balance-B 50b, yaw balance-A 50c, and yaw balance-B 50d. All of these signals connect to connector 27 of the wire harness. 
     These signals are used for pre-launch alignment of the launcher control signals to the missile electronics. At launch, these wires are severed. 
     The remaining control signals, as first described in FIG. 4, are handled by the circuitry shown in FIG. 6. 
     Control signals 41a, 41b, 41c, and 41d are amplified to generate the pitch 4 actuator signal 60a, the yaw 1 actuator signal 60b, the pitch 2 actuator signal 60c, and the yaw 3 actuator signal 60d. These signals are communicated to the appropriate actuators via connector 27 of the wire harness. As is obvious to those of ordinary skill in the art, these signals are used for the manipulation of the control surfaces for flight control. 
     FIG. 7 illustrates the missile and missile system of the preferred embodiment, a tube-launched missile and system. 
     The missile&#39;s components are contained within a body 70 with control surfaces 73. Wings 77 assist the control surfaces 73 in maintaining and directing the missile during flight. 
     Beacons 72a and 72b assist the operator to visually identifying and track the missile after launch. 
     Also within missile 75 is the launch motor 76, the warhead 78, the extensible probe 79, flight motor 74, and the launch motor 76. These components are well known in the art and their functions are as their titles indicate. 
     Permitting the operator interface 16 to communicate with the missile 75 is the communication link, composed of wire dispensers 71 and wire 71a. Wire 71a is a steel wire. 
     In this manner, the operator communicates directions to the missile 75 via the operator interface 16 and communication link 71 and 71a. The directions from the operator are combined with the positional status of the missile by the electronics unit [not shown] to properly manipulate the control surfaces 73. 
     It is clear from the forgoing that the present invention creates a superior and more versatile missile.