Abstract: A doppler video signal conditioning circuit comprising first, second and rd buffers which respectively receive a voltage controlled oscillator signal, a second intermediate frequency signal and a second local oscillator signal from a missile' radar receiver. The buffered voltage controlled oscillator, second intermediate frequency and second local oscillator signals are then supplied to a doppler processing circuit. The doppler processing circuit processes these signals, providing at its output a reconstructed doppler video signal which includes a marker which is 20 kHz above the frequency the missile's radar is tracking. The doppler processing circuit provides the reconstructed doppler video signal to an analog-to-digital converter. The analog-to-digital converter digitizes the reconstructed doppler video signal before supplying the digitized signal to a frame controller.

Abstract: A three dimensional imaging system that utilizes an ultra-wideband radar circuit, a focused radar antenna, an erasable programmable read only memory (EPROM) means which includes a translational software program for translating radar signals received from the radar circuit into signals representing three dimensional coordinates, a memory means 13 for storing the translated signals, and a Computer Aided Design (CAD) program means for processing the translated signals into three dimensional images.

Abstract: The present invention is a block adaptive quantizer and an associated VLSI processor to provide real-time data compression for high resolution imaging radar systems. The block adaptive quantizer receives data from a synthetic radar aperture in a burst-mode. The block adaptive quantizer encodes and quantizes the data via a data-compression scheme. The image data is encoded by the block adaptive quantizer using thresholds generated from current bursts of image data collected.

Abstract: The radar system comprises a transmitter unit and a receiving unit for radar signals, a trigger unit for guiding the radar signals from the transmitter unit and an aerial unit for transmitting the radar signals from the transmitting unit and for receiving reflected video signals. The transmitter unit and receiving unit each comprise at least two separate transmitters and receivers. All of the transmitters and receivers are triggered off by a common trigger which is arranged to trigger each individual transmitter mutually in series during a sequence period so that the transmitters produce signals with mutually distinct frequencies/characteristics. The individual receivers are matched to the respective transmitters to be able to present the frequencies/characteristics of video signals in approximately the entire sequence.

Abstract: A range cell formation process that are used to enhance the quality of an image following a perspective transformation from range-azimuth coordinates (B-scan) into elevation-azimuth coordinates (C-scan). The present range cell formation process eliminate situations where there are missing data points at the far range, and large areas that have the same data point at the near range. The range cell formation process evaluates the data content in range cells on a case by case basis using a prioritized system to determine what is to be displayed so that a high level of image contrast is maintained. In the far range, range cell data that are in between range points defined by every two adjacent elevation points are processed and a priority system is used to determine the best intensity value to use for the elevation points. The priority system is such that bright objects have the highest priority, followed by dark objects, and then followed by an average background level.

Abstract: A radar encoder comprising a delta modulation circuit which receives analog adar video data from a radar and then converts the data to digitized NRZL video data. The radar encoder also has an encoder circuit which receives the digitized NRZL video data as well as a trigger pulse signal and analog synchro signals from the radar. The synchro signals are provided to a Synchro-to-Digital Converter which converts the synchro signals to sixteen digital synchro data bits which are then latched into the converter. The synchro data bits are next parallel transferred to a pair of shift registers and then clocked in a serial format to a multiplexer. The multiplexer also receives the digitized NRZL video data supplied to the encoder circuit. A state machine, in response to the trigger pulse signal, generates control signals to latch the synchro data bits into the converter and then effect the parallel transfer of the synchro data bits from the converter to the shift registers.

Abstract: A plurality of threshold detectors is provided to pass analog signals of predetermined and varying threshold values. An analog to digital converter converts these analog signals to binary 1s and 0s. A target detected on each radar beam sweep is a 1 and no target is a 0. These binary numbers are then stored in a reversible up-down counter. At the first signal received, the counter counts up on hits (binary 1) and counts down on misses (binary 0). When the contents of the counter reaches a predetermined count, a target's leading edge is declared. At this time, the counter is then reset and proceeds to count up on misses and down on hits until the aforesaid predetermined count is attained, wherein a trailing edge is then declared.

Abstract: A radar decoder circuit for converting NRZL Data to radar video data which s supplied to a radar video display screen. The radar video circuit includes an Erasable Programmable Logic Device which decodes incoming NRZL data to identify a frame sync having twenty four data bits. When the frame sync is identified the location of sixteen bits of synchro data is also determined. The synchro data is then latched into a latch within the Erasable Programmable Logic Device for processing by a Digital-to-Synchro Converter. Control signals for effecting a transfer of the synchro data to the Digital-to-Synchro Converter are provided by enable and latch signal generating circuit within the Erasable Programmable Logic Device. The Digital-to-Synchro Converter converts the digital synchro data to analog synchro signals which are supplied to the radar video display allowing the display to indicate the direction the radar from which the NRZL data is received is pointing.

Abstract: Disclosed are a device for the detection of S mode responses received by a secondary radar receiver and its use for the filtering of the pulses contained in this response. The device furthermore comprises means to detect a signal S, means for the real-time computation of the mean values of magnitudes characterizing the pulses that belong to the response, and means for the filtration, by comparison, of the values of the magnitudes measured on each pulse detected with the mean value of the corresponding magnitude.

Abstract: Radar apparatus provided with a signal generator (1), transmitter means (2), antenna means (3), receiver means (4), a video processor (6) and an indication device (7) for the generation of a radar picture of the surroundings of the radar apparatus with a first resolution. A selected target, designated with control unit (8), may be displayed on the indication device (7) with a second, higher resolution. To this end signal generator (1) generates in the direction of the selected target control signals for transmitter (2) with an increased bandwidth. Selection and conversion unit (5) matches echoes of these increased bandwidth signals to the bandwidth of video processor (6) and indication device (7).

Abstract: A radar indicator comprising a source of radar image signals having a first (r,.theta.) format and a digital scan converter responsive to the radar image signals for converting the radar image signals from the first format to digital radar image signals having a second (X-Y) format. The digital scan converter includes an image memory for supplying the digital radar image signals having the second (X-Y) format. A source of external video image signals having the second format, including video synchronization signals is provided. A synchronization signal stripper and clock signal generator circuit is responsive to the video synchronization signals of the external video image signals for generating a clock signal synchronized with the synchronization signals of the external video image signals.

Abstract: An entropy based signal transmission, reception and analysis method and apparatus in which the entropy of time dependent signals is determined by utilizing a selected Green's function relationship. Information with respect to a medium with which the signals have interacted is derived by comparison of the entropies of the signals. In a preferred embodiment, the density distribution functions of selected digitized time segments of the signals to be analyzed are determined by utilizing the selected Green's function relationship and the entropies of the signals are then determined from the density distribution functions and compared with each other to derive the desired information.

Abstract: This system for displaying data on a display unit comprising a television screen associated with a videographic memory, the data containing at least one videographic signal and scanning data, a pre-processing unit for reel time programming the output data of the radar, a threshold unit for thresholding the videographic signal from its background noise, and a digitizer circuit for digitizing the videographic signal after thresholding, a compression circuit for space-time compressing the videographic signal after digitization, a transmission device for proprietary serial data transmission of the scanning data, of the compressed videographic signal and of compression data, to the television display assembly unit, which comprises a decompression unit for decompressing the videographic signal and a converter unit for converting the standard of the coordinates of the data contained in this signal, from a polar coordinates into a Cartesian coordinates with the aid of the compression and scanning data, and control de

Abstract: A digital video quantizer for use in TCAS and ATCRBS/SIF systems. A digital delay receives a digitized video signal and produces a plurality of delayed digital signals which are used throughout the quantizer. A threshold generator then produces a predetermined threshold and a dynamic threshold, and a quantized video generator compares one of the delayed digitized signals to a threshold to produce a quantized video signal. A slope quantizer detects a slope of the digitized signal which exceeds either a positive or negative threshold. In addition, a rise time detector detects an excessive rise time in the digitized video signal, and a chip amplitude comparator provides a signal which is used in detecting Mode S data bit values. The digital video quantizer's use of digital references rather than analog references, eliminates the inaccuracies caused by a reference voltage varying over time or temperature. The digital references also facilitate modification of the reference values at a later time.

Abstract: A video signal processor for a radar system includes A/D converters for receiving radar signals to digitize the signals at a predetermined speed, direct averagers for writing signals included in the predetermined size of azimuth among the digitized radar signals into different memories according to the azimuths and for averaging signals corresponding to the same range gates, cell average processors having a microcomputer and a RAM for cell-averaging the output of the direct averagers with the processing program down-loaded from a main controller, an extractor for extracting only target data from the output of one of the cell average processors, a radar video processor controller for generating various control signals, and a communication processor for performing the data transmission and reception between the main controller and the radar video processor controller of the radar system.

Abstract: The invention provides improved focus by phase corrections for Synthetic Aperture Radar images by operation on the range bin containing a selected isolated target. A phase correction signal is generated by first obtaining a non-interfering radar return from the selected target through band pass filtering operation and then extracting a non-linear residual phase from the band pass filtered data with an arc-tangent generator. The residual phase derived by the arc-tangent generator is then applied to the range compressed SAR data as a phase correction signal.

Abstract: A radar equipment comprising a display unit (FIG. 1) and a scanning unit (FIG. 2) linked together by electrical conductors (94,72,106,26) for the transmission of information and/or control signals between the units, and circuitry (90,98; 66,69; 102,108; and 25,162, respectively) for superimposing on an individual conductor more than one of the signals.

Abstract: A pulse marine radar system having a threshold generator providing a range dependent threshold waveform which is a function of sea conditions, rain conditions, and radar parameters. Based on the radar settings and inputs from the operator regarding the sea and rain conditions, a processor uses a mathematical model to compute the mean of sea clutter, rain clutter, and receiver noise for each of a plurality of successive range intervals. In response to the mean values, a generator generates a range dependent piecewise linear analog waveform which is subtracted in range sychronism from the receiver video. Next, the video is filtered. For each range interval, the processor also calculates a threshold based on the probability of sea clutter, rain clutter, and receiver noise exceeding the threshold after subtracting the mean. In response to the threshold values, a generator generates a piecewise analog signal which is compared with the output of the filter to digitize the radar video.