Abstract: A target tracking radar receiver for use in a semiactive tracking system wherein elevation angle data, azimuth angle data and Doppler frequency shift data are processed in a manner which enables narrow band filtering of target angle tracking data in the first intermediate frequency stage. The receiver is arranged to track, simultaneously, variations of target Doppler frequency and of transmitter frequency to permit the desired early narrow band filtering of the received angle data.

Abstract: A combined infrared-radar detection system wherein a radar antenna also serves as the primary mirror in an infrared focusing arrangement.

Abstract: A target tracking radar receiver for use in a semiactive tracking system wherein elevation angle data, azimuth angle data and Doppler frequency shift data are processed in a manner which enables narrow band filtering of target angle tracking data in the first intermediate frequency stage. The receiver is arranged to track, simultaneously, variations of target Doppler frequency and of transmitter frequency to permit the desired early narrow band filtering of the received angle data.

Abstract: A system and method that uses differential computation of position relative to a global positioning system (GPS) coordinate system and the computation of an optimum weapon flight path to guide a weapon to a non-moving fixed or relocatable target. The system comprises an airborne platform that uses a navigation subsystem that utilizes the GPS satellite system to provide the coordinate system and a synthetic array radar (SAR) to locate desirable targets. Targeting is done prior to weapon launch, the weapon therefore requires only a navigation subsystem that also utilizes the GPS satellite system to provide the same coordinate system that the platform used, a warhead and a propulsion system (for powered weapons only). This results in a very inexpensive weapon with a launch and leave (autonomous) capability. The computational procedure used in the platform uses several radar measurements spaced many degrees apart. The accuracy is increased if more measurements are made.

Abstract: A tracking radar system comprising an aerial arrangement having a plurality of outputs, means for deriving from the aerial outputs a sum signal representative of the sum of the aerial outputs and a difference signal representative of the direction of a target relative to the aerial, a receiver for processing said sum and difference signals to produce corresponding intermediate frequency sum and difference signals, means for comparing the intermediate frequency sum signal with the output of an oscillator in a first phase-locked loop and using the resulting signal to control the oscillator frequency so as to cause the oscillator to lock on to the frequency of the intermediate frequency sum signal, a phase-sensitive detector for comparing the intermediate frequency difference signal with the output of the oscillator to produce an output signal representative of the phase difference between the sum and difference signals, and bandwidth alteration means responsive to the sum signal to alter the bandwidth of the fi

Abstract: An underwater maneuverable vehicle is presented which carries an explosive charge and can be used for immediate removal or destruction of various menaces to navigation and other underwater hazards. The battery powered vehicle is air dropped from a platform which carries an imaging lidar system for detection and is operated and navigationally controlled in conjunction with an imaging lidar system.

Abstract: An underwater maneuverable vehicle is presented which carries an explosive charge and can be used for immediate removal or destruction of various menaces to navigation and other underwater hazards. The battery powered vehicle is air dropped from a platform which carries an imaging lidar system for detection and is operated and navigationally controlled in conjunction with an imaging lidar system. In accordance with an important feature of this invention, an optical lidar downlink is used to control the submerged underwater maneuverable vehicle from an airborne platform. The downlink is pulse spaced modulated. Command signals are secure, and are decoded aboard the vehicle. Control in speed, heading and depth, as well as command detonation are available using this technique.

Abstract: A method and apparatus that uses iteration to achieve a better prediction of the values of the commands needed to balance the gains of .SIGMA.+.DELTA. and .SIGMA.-.DELTA. channels of a radar guidance system, when an imbalance occurs due to a change caused by the AGC circuitry. An improved method of measuring channel-to-channel gain imbalance versus AGC measurements is provided, which produces modified input values that are used as commands that correct the mismatch during missile flight so that residual error is minimized and more accurate guidance is achieved. The present method is implemented by measuring the gain imbalance at predetermined AGC points during system calibration, and iterating these measurements to produce a relatively small channel-to-channel gain imbalance at the .DELTA.AGC amplifiers. The measured imbalance is then converted to .DELTA.AGC commands and applied to the .DELTA.AGC amplifiers. The resulting gain imbalance is measured and this value is added to the originally measured value.

Abstract: An AWTSS is shown to be made up of an improved synthetic aperture radar (SAR) for generating radar maps with various degrees of resolution required for navigation of an aircraft and detection of ground targets in the presence of electronic countermeasures and clutter. The SAR consists, in effect, of four frequency-agile radars sharing quadrants of a single array antenna mounted within a radome on a "four axis" gimbal with a sidelobe cancelling subarray mounted at the phase center of each quadrant. Motion sensors are also mounted on the single array antenna to provide signals for compensating for vibration and stored compensating signals are used to compensate for radome-induced errors. In addition, a signal processor is shown which is selectively operable to generate radar maps of any one of a number of desired degrees of resolution, such processor being adapted to operate in the presence of clutter or jamming signals.

Abstract: A missile guidance antenna that is conformal to the missile surface, dual-polarized and broadband. Slotline notch array elements (30, 52) are inclined toward boresight for both the E and H-planes. This inclination directs a greater portion of the energy toward the front of the missile. The additional energy directed forward reduces the nullifying effects of the metallic skin on the tangential E-field and enhances the performance of the other polarization. The slotline elements (30, 52) can be packed with spacing close enough to allow for electronic beam steering without creating grating lobes in the field at the highest frequency of operation.

Abstract: A pulse radar for operation at 94 GHz and higher frequencies is shown to include an antenna, a diplexer and first detector that are each optically fed so that radio frequency signals may be, when transmitting, passed through the diplexer to the antenna and, when receiving, from the antenna through the diplexer to the first detector.

Abstract: A vehicle mounted radar tracking system monitors vehicle heading rate, vehicle heading acceleration, vehicle roll rate and vehicle pitch rate, and provides a turn detect signal in response to heading rate, heading acceleration, roll rate or pitch rate being in excess of corresponding enable threshold magnitudes. In response to the turn detect signal, the tracking system dead reckons the positions of targets being tacked, and tracking system parameters are varied to make it more responsive to target motion. The turn detect signal is removed in response to heading rate, heading acceleration, roll rate and pitch rate being less than corresponding disable threshold magnitudes, and the tracking system is returned to normal operation.

Abstract: An adaptive RADAR environmental signal filter (1) is described which selectively preprocesses RF RADAR input data prior to the data's utilization by a processor (8). The filter (1) consists of an array of parallel discriminator cells (165) which compare incoming RF RADAR data to a window parameterized by predetermined threshold values. The array of discriminator outputs are networked through combinational logic (59) in order to provide an output correlation signal (63) to an external processor (8). A discriminator enable latch (55) synchronizes the discriminator outputs as the outputs pass through the combinational logic (59).

Abstract: A vehicle mounted radar system has an antenna (12) which rotates about a reference axis (19). During angular movement of the antenna with respect to the reference axis, a radar indicated target azimuth (.phi.') is modified to provide a corrected target azimuth (.phi.) which is substantially indicative of the actual or true target azimuth. A tracking system (25) uses a predicted radar indicated target position (P.sub.n+1 (x,y)) for target tracking and correlation. The tracking system uses a smoothed target position (STP(x,y)), indicative of actual target position, for providing a visual display (39) of target track.

Abstract: The present invention relates to ground-based electromechanical search and communications apparatus used in conjunction with airborne communications apparatus. The ground-based apparatus maintains contact with and determines the precise location of the airborne apparatus within a defined space. Additionally, the airborne apparatus may receive data from a satellite system as to its inertial coordinates within object space. The apparatus of the invention includes a ground-based electronically and/or mechanically controlled antenna, an integral transmitter and computer and an airborne transceiver with an integral antenna and computer. The airborne transceiver transmits to, and on occasion receives, discrete commands from the ground-based apparatus. The ground-based apparatus via transmissions received from the airborne apparatus, will be able to determine the precise location in object space of the airborne apparatus and extrapolate its future location.

Abstract: A pulse radar for operation at 94 GHz and higher frequencies is shown to include an antenna, a diplexer and first detector that are each optically fed so that radio frequency signals may be, when transmitting, passed through the diplexer to the antenna and, when receiving, from the antenna through the diplexer to the first detector.

Abstract: A broad band multimode seeker system for a missile includes a wide band phased array transmitter/receiver unit incorporating a wafer scale phased array device with a bandwidth of about 2 GHz to 35 GHz. A multimode intermediate frequency unit selectively generates radar and jamming waveforms and measures parameters of reflected radar and external emissions of RF energy. A guidance processor manages the front end assets for selective active or semiactive radar searching and tracking, and simultaneous searching for, tracking of, homing on, and applying a selection of electronic countermeasures to, multiple defensive radars. Confirmation of an assigned target is made through correlation of received RF signals with libraries of expected defensive system parameters and high resolution target profiles and preloaded target geographical coordinates.

Abstract: A fiber optic radar guided missile system 10 is disclosed which includes a radar receiver 12 disposed in a missile for receiving radar reflections and providing a first optical signal in response thereto. An optical receiver 14 is disposed at a launcher for receiving the first optical signal and for providing a set of electrical signals in response thereto. A fiber optic link 32 is connected between the missile and the launcher for communicating the first optical signal from the radar receiver 12 to the optical receiver 14.In a specific embodiment, the invention 10 includes a first system 12 disposed in a missile for receiving radar reflections which includes only an antenna 16 for receiving radar reflections, a radar seeker 18 for providing a first electrical in response to the received radar reflections, and a first fiber optic transmitter 26 for converting the first electrical signal into a first optical signal.

Abstract: A method of aligning two images of the same scene by matching features in a first image to features in a second image is disclosed. The method comprises identifying edges of objects in the first image using two different processes. The edges identified using both processes are compared and combined into one image representing confirmed edges which are readily identified in other images of the same scene. A template is then formed from the confirmed edges which is matched to a subregion of the second image.

Abstract: A radar system operating by the line-of-sight method requires an accurate measurement of the relative position of at least two objects. By sending out coded radar transmission pulses, control data are transmitted to a guided flying body in a radar beam, which sends back an echo signal to the receiver via a transponder. In order to measure the passive signal and the transponder echo signal in the radar beam as accurately as possible, common reception channels are provided for both echo signals containing, inter alia, arrangements to equalize the dynamic levels of the echo signals. The returned transponder echo signal corresponds with respect to coding and bandwidth to the transmission pulses originally generated in the transmitter and that are phase-coded but not provided with the control code.

Abstract: Air-to-ground radar (2) is stabilized by comparing the power of the returning echo occurring during an initial period after the transmission of each pulse with that occurring during a following period after the transmission of each pulse, and using the result of this comparison to control an elevation controller (13) of the radar (2). Means (7, 8) provide a first power signal representative of the power of the returning echo occurring during an initial period after the transmission of each pulse, means (7, 9, 10) provide a second power signal representative of the power of the returning echo occurring during a following period after the transmission of each pulse, and a comparator (12) compares the magnitude of the first and second power signals and outputs a control signal causing the elevation controller (13) to raise or lower the elevation at which output pulses are projected.

Abstract: A semi-active radar receiver for receiving a sequence of radar pulses and providing radar timing signals in response thereto. In a most general sense, the semi-active receiver of the present invention includes a receiver 10 for receiving a direct transmission of a series of pulses from a radar transmitter 2 and for providing a series of first signal pulses in response thereto. A range gate generator 42 is included for processing the series of first pulses to provide said radar timing signals. In a more specific embodiment, the receiver includes a filter 40 for processing said received pulses and deriving estimates of the timing of the receipt thereof. The estimates are then used by the range gate generator 42 to provide said radar timing signals.

Abstract: A method and apparatus for identifying inertial reference unit (IRU) errors in a guided missile employing a multi-mode guidance system and constructing correction terms to recover the missile true position. Discrepancy parameters are introduced to indicate misalignment between missile and launching platform (or ship) inertial frames where the missile onboard executive computer simultaneously processes the data provided from missile onboard sensors and target relevant data uplinked from the launching platform. The discrepancy parameters are employed to construct correction factors used to reduce the discrepancies. This updated missile configuration is then coupled with the target state estimator outputs to reconstruct smoothed line-of-sight (LOS) angles for terminal homing engagement.

Abstract: A missile guidance system having means for deriving from a target angle tracking loop a signal indicative of an apparent movement of a target off a missile-to-target sight line caused by a change in missile attitude, and means for feeding said apparent movement signal into a space stabilization loop to adjust the position of the aerial to compensate for said apparent movement.

Abstract: A signal acquisition circuit for a missile guidance system has a phase lock loop which is responsive to incoming signals received from a target and will lock on to the frequency of the received signal. The bandwidth of the phase lock loop is altered in dependence on the signal being received in order to distinguish between a valid target and noise.

Abstract: A high frequency target seeking device, using a stabilized reflector antenna, performs range search and tracking functions and target angle search and tracking functions. A technique is provided for target range discrimination using several narrow band i.f. filters, also thereby improving signal-to-clutter ratio and signal-to-receiver noise ratio. Target search is accomplished with simultaneous range and antenna azimuth scanning, with the range bins and the antenna beam swept across the target. A multiplexer selects the range bin having signals indicative of the target. Target range tracking is accomplished by the multiplexer additionally automatically selecting range bins adjacent to the target's range bin and comparing their output signals. Antenna stabilization is accomplished utilizing signals from vehicle pitch, roll, and yaw rate sensors, and antenna elevation and azimuth rate and angle sensors.

Abstract: A guided missile having a radar system which is utilized as a target seeker and tracking radar as long as it is capable of tracking the target through the encounter, after which, or at some set distance from the target, the radar and associated circuitry provides the optimum burst time.

Abstract: An automatic landing system for landing remotely piloted flying vehicles ng a predetermined path and at a predetermined point. The system includes an autopilot carried by the flying vehicle for measuring the parameters of attitude, airspeed, and heading and for comparing the measured parameters with the inputted parameters for the desired attitude, airspeed and heading. The autopilot adjusts the vehicle controls to make it conform to the desired attitude, airspeed and heading when deviations therefrom are detected. The system includes a radar transmitter and receiver means disposed on a stabilized double gimbal for measuring the actual heading and distance from the vehicle to the radar transmitter and receiver on a continuous basis.