Abstract: A method and apparatus which perform efficient projection of 4-dimensional data (3 spatial and 1 time dimension) onto planar grids are described. Multiple frames of data are drawn from a limited time history data buffer and projected onto a planar grid, which need not be flat, defined in its own coordinate system. Higher dimensional data structures can also be formed from multiple projection grids. Measurement data from multiple data frames is projected into the planar grid such that distance out of plane is the z-dimension. Computational efficiency is achieved by processing only those data samples that are relevant to the planar grid. To be considered relevant, the impulse response of the sensor's measurement rays must cross the planar grid. Samples of relevant rays must also map onto the planar grid's coordinate mesh to be relevant. Multiple data measurements may determine the planar grid's final amplitude result.

Abstract: The present invention relates to a radar video display and recording device, which can simultaneously display radar video signals of the whole and designated areas in the polar coordinates and Cartesian coordinates, respectively, and can store the radar video signals of the designated area in a hard disk drive (HDD) for obtaining long-time continuous radar video information for subsequent analysis and algorithm verification. A radar video capture card is utilized on a personal computer (PC) or workstation platform to analyze and store radar video signals of the whole and designated areas and to simultaneously display video signals at different processing stages in a digital video processing unit on a scope for monitoring the work condition at each processing stage.

Abstract: A process is provided for near real-time or real-time software based scan conversion in a general purpose computer. The general purpose computer receives data via a digital network comprising range scaled and window detected radar video and antenna azimuth data in polar coordinate format according to the Andrusiak et. al. U.S. Pat. No. 5,923,285. The general purpose computer integrates the polar data into a polar buffer prior to conversion to Cartesian coordinates for display. This process de-couples the polar buffer from the coordinate conversion process so that the polar buffer process keeps up with incoming real-time data. The coordinate conversion process is given some portion of the remaining processor bandwidth such that even if it does not keep up with the real-time rate of the radar, it will display all target information. The polar buffer processing involves integration of the new data with old data in the polar buffer in order to preserve target information until it has been displayed.

Abstract: Disclosed is a three-dimensional radar apparatus comprising a radar transmitting/receiving unit, a three-dimensional polygon-generating unit, and a three-dimensional graphics unit, wherein a radar transmitter/receiver outputs signals concerning orientation information, distance information, and reception intensity information on the basis of a radio wave reflected from a target, and a scan converter is used to convert the signals concerning the orientation information, the distance information, and the reception intensity information into two-dimensional radar image data composed of two-dimensional rectangular coordinates and brightness information of each of picture elements. The two-dimensional radar image data is also inputted into the three-dimensional polygon-generating unit to perform polygon-generating processing on the basis of the two-dimensional rectangular coordinates and the brightness information of each of the picture elements.

Abstract: A three-dimensionally designed display radar in which a two-dimensional image data and three-dimensionally designed image data are depicted in combination in a video memory by the aid of an image controller, and they are simultaneously depicted on a screen of a display unit.

Abstract: The present invention provides a radar apparatus and like systems and method which comprise coordinate converting means for signals defined in a polar coordinate system to corresponding signals defined in Cartesian coordinate system, an image memory, and an indicator with pixels the number of which being the same as that of memory elements of the image memory, and further comprise means for drawing imaginary first and second sweep lines on pixels or memory elements of the image memory to determine a first sample point for a pixel on the second sweep line or to determine a last sample point for a pixel on the first sweep line, and perform a signal processing such as data correlation or interpolation in response to the detected last sample point or the first sample point detected so that displayed image quality is improved.

Abstract: A process provides radar scan conversion from radar amplitude data in polar coordinates to rectangular coordinates by a digital computer which receives (r,.theta.) coordinate amplitude data from a radar receiver and which supplies (x,y) coordinate amplitude data which covers a rectangular-shaped display area of a monitor display. A software program generates an aggregate radial scan pattern that consists of a plurality of radials each of which have active lengths that span one or more of a plurality of selected regions of the display such that the region boundaries are square as a result of a modified radial drawing method. Each resolution region is defined by the bisection of the radials forming the previous resolution region and the hole-filled range of the previous resolution region. The display can be generated as an offset display where the antenna center may be offset from the display center.

Abstract: In a plurality of shift registers which receive M.multidot.n-tuple speed data divided into plural parts, execute modulation of the data, and output modulated data as n-tuple speed data, a period of time required from a start of inputting M.multidot.n-tuple speed divided data as a modulation object to an end of outputting n-tuple speed modulated data is set within one period of an M.multidot.n-tuple speed frame clock.

Abstract: A radar scan converter and method of mixing image. By inserting a radar scan converter (RSC) card in a personal computer, an input video such as a radar video or supersonic video can be mixed on a screen of the personal computer without deteriorating the current graphic, such as range rings, plots, tracks, and symbols. An analog-to-digital converter, a radial buffer, a decimation filter, a coordinate converter and an overlay processor are used in the radar scan converter. The overlay processor read a display memory on a display card according to a triangular coordinate generated by the coordinate converter. The read data from the display memory is then compared. When the read data do not contain either text or graphic, a data processed by the decimation filter is written into the display memory.

Abstract: The Radar Scan Converter receives range and azimuth data that is generated by a conventional radar and presented in a polar coordinate system, and processes and displays this data, in real time, on a conventional generally rectangular display screen which has a display formed by a relatively large number of pixels organized in the X- and Y-axes of a Cartesian coordinate system. The Radar Scan Converter sequentially updates each pixel in the display by (1) selecting a pixel address in the Cartesian coordinate system, (2) determining the corresponding cell address in a direct display memory interface, (3) reading the video level in this corresponding cell, (4) then responsive to this respective video level, either initially loading or subsequently updating the associated pixel in a screen image memory, and (5) refreshing the display from the screen image memory through respective cycles over repeated radar scans.

Abstract: A system for the distribution of digitized radar video over a digital network is presented. The digital network is located at the low data rate point in the radar scan conversion process resulting in low network bandwidth with no loss of video fidelity. The conversion from analog to digital distribution allows for a totally integrated information network eliminating the need for a dedicated radar distribution network. This approach broadens the use of radar data from traditionally dedicated consoles to all network users. The radar and display system architecture consists of one or more radars and displays. Each radar has a video digitizer and azimuth decoder that is coupled to receive radar analog signals representative of radar data in polar coordinates or other format, which are constructed to provide digital signals representative of said analog signals.

Abstract: The Radar Scan Converter System (1) receives range and azimuth data generated by a conventional radar as presented in a polar coordinate system, (2) stores this data in associated cell locations in a range/azimuth polar video map, and (3) displays this polar coordinate range/azimuth data in a Cartesian coordinate system, in real time, on a conventional computer monitor having a rectangular display formed by a relatively large number of pixels organized in the Cartesian coordinate system. Each pixel in the display is sequentially update by (1) selecting a respective pixel address, (2) determining the corresponding range/azimuth cell address in the polar video map, (3) reading the video level in this corresponding range/azimuth cell, and (4) in response to this associated video level, either initially loading or subsequently updating the selected pixel.

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 scan conversion from radar data in polar coordinates to radar data in rectangular coordinates is employed to supply (x,y) coordinate data to a display, which has variable azimuthal pixel resolution that increases from the center of the display to its periphery. An aggregate radial scan pattern is generated on the display that consists of a plurality of radials each of which have active lengths that span one or more of a plurality of selected boundary resolution zones of the display. These zones are defined by a series of different hyperbolically-based resolution boundaries which define resolution zones of increasing azimuthal resolution values as the zones extend further from the center of said display towards the periphery of said display. The number of radials that are generated on said display match the average azimuthal resolution of said display for each zone.

Abstract: A process provides radar scan conversion from radar amplitude data in polar coordinates to rectangular coordinates by a digital computer which receives (r,.theta.) coordinate amplitude data from a radar receiver and which supplies (x,y) coordinate amplitude which covers a rectangular-shaped display area of a monitor display. A software program generates an aggregate radial scan pattern that consists of a plurality of radials each of which have active lengths that span one or more of a plurality of selected zones of the display such that as the average azimuthal resolution associated with each zone increases, the number of generated radials match the average azimuthal resolution of the display for each zone. The display can be generated as an offset display relative to the antenna center of a display that has no offset.

Abstract: A pseudo-code representation and a C language representation of a scan converter system whereby radar amplitude data specified in polar coordinates may be displayed on a computer monitor display controlled by rectangular coordinates is provided. The invention utilizes a look-up table that is built using a two-phase algorithm. The look-up table is set into an initial state after which a mapping process takes place in which all of the (x,y) coordinate values covering the display area are inversely projected to the nearest (r,.theta.) coordinate values using trigonometric and approximation procedures. Since more than one (x,y) value may map to the same (r,.theta.) value, these values are linked together to form a patch. All of the (r,.theta.) coordinates will not be hit in this mapping process. Therefore, a second phase of projection occurs. Each (r,.theta.

Abstract: A device for displaying an image delivered in particular by a radar on a screen of a television monitor associated with a videographic memory the contents of which are controlled by a control assembly for the control of the display and reception of the image to be displayed, the control assembly functions in conjunction with an after glow processor for processing the contents of certain zones of the videographic memory in accordance with a given law a mathematical treatment formula for producing a pseudo-after glow phenomenon of certain points of the radar image displayed on the screen.

Abstract: A high speed and high precision coordinate transformation process for transforming image data in range-azimuth coordinates to horizontal-vertical display coordinates. The process is comprised of the following steps. Recursion initialization parameters and values for a perspective transformation are computed. Then, range and azimuth values using predetermined recursion equations are computed. A critical range factor using predetermined recursion equations and inverse operation is computed. Range and azimuth results are computed. Display address values are computed. Data is retrieved and the data is stored in display locations. A decision is then made whether the last display address has been stored. Additional display address values are computed until all addresses have been computed, and the process is ended once all addresses have been computed.

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: A device for converting data for display on at least one television screen associated with a videographic memory, the output signals of the radar comprising at least one videographic signal and scanning data, the device comprises a processor for processing the different radar output data, an analog/digital converter for digitizing the videographic signal, a videographic signal converter for compressing the digitized videographic signal, a distance marker generator for generating distance markers, a polar to Cartesian converter for converting the standard of the coordinates of the data contained in the signal from a polar coordinate system into a Cartesian coordinate system, an intermediate memory for receiving and storing the compressed videographic signal and the distance markers, an output buffer memory for receiving and storing the output signals of the intermediate memory and the polar to Cartesian converter and an interface for controlling the memory as a function of the data contained in the buffer memo

Abstract: A plan position indicator display is converted to a correctly scaled perspective display based on aircraft altitude and display parameters. Two cartesian based display memories are involved. One memory stores the plan position indicator image to be converted and the other memory stores the converted image ready for direct display on a bit-mapped display device. The arrangement is such that a plan position indicator display pixel address is provided for each pixel in the memory which stores the converted image for permitting said latter memory to be completely filled with the most appropriate pixel values at the frame rate without the need for further pixel filling or erasing.

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: By performing rotation and translation operations, a radar display converts a radar signal to radar image information expressed in a three-dimensional orthogonal coordinate system with horizontal, vertical, and depth coordinates related to a certain viewpoint. Terrain and target information is converted to the same coordinate system and combined with the radar image information, producing a realistic three-dimensional display. Clipping is performed in the depth direction to eliminate portions of the radar image disposed behind terrain or target images. Terrain and target images disposed behind the radar image are reduced in intensity, but not clipped. Perspective projection and zoom transformations may also be carried out.

Abstract: Radar data vectors of a desired number of pixels in length are scan converted, at a desired angular rate. A complete 360 degree radar data scan is maintained in memory. A raster image of a desired number of pixels in size and of arbitrary position and angular orientation with respect to the radar scan in memory is outputted. The resolution of the raster output image is varied to adjust its update rate. A high resolution, motion stabilizing radar display is provided and a multiresolution capability is available to eliminate image artifacts attributed to raster image update rate.

Abstract: A radar of particular use at close range has a CRT that is scanned in a spiral fashion by applying phase quadrature sinusoidal signals to resonant deflection coils. A digitizer converts the radar return signals to multi-bit signals which are supplied to a memory with signals for alternate pixels stored in different halves of the memory. The apparatus reads out signals from one half of the memory during one scan and reads out signals from the other half of the memory during the next scan so that they are interleaved with the pixels on the display brightened by the first scan.

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 present invention relates to a raster scanning radar display apparatus which is capable of improving the display of echo signals from objects in the vicinity of a ship on the display surface of an indicator. The raster scanning radar display apparatus includes a memory for storing echo signals based on one search signal, a sweep scanning device for drawing a plurality of imaginary sweeps which are parallel with each other in a display memory each time the pointing bearing of the antenna is varied and for generating signals representative of addresses of memory elements in a display memory scanned by the sweeps. The apparatus whites echo signals into the memory elements of the display memory scanned by one sweep and writes predetermined signals into the memory elements of the display memory scanned by other sweeps. The signals in the disply memory are read and displayed on an indicator.

Abstract: A method and apparatus for displaying radar data on a display monitor, wherein the monitor is divided into octants, and wherein the radar data defines a pie-shaped slice to be displayed within an octant on the monitor. The radar data has a center point which is defined as a point on an x-y plane, a radius r which is a defined as a number of displacement units in length extending radially from the center point, a starting angle .theta., a delta angle .differential..theta., radial displacement data which defines the color of groups of displacement units along the radius r for the slice, and a quantity Q which is the number of groups of radial displacement data within said radar data. The radar data is received by a data processing system and stored in memory. The video display monitor is updated by a screen refresh memory controlled by a graphics accelerator.

Abstract: A radar system that enhances the display of moving targets by using negative scan-to-scan correlation to determine which pixels will be displayed at the brightest level. More specifically, a bit image stores a multi-bit scan-to-scan correlated history for each pixel on a display screen, and when new video data is received on a scan, the bit image memory is modified in accordance therewith. A pixel is enhanced to the brightest level only if a return is received from a spacial location from which returns were not received on previous scans. Thus, a target that moves to a new location is displayed at the brightest level because it doesn't correlate with returns from prior scans.

Abstract: A new architecture for the implementation of radar displays is provided which uses a mixed architecture superposing a PPI (Plan Position Indicator) type display on a raster display. The polar (analog) signal and the cartesian (digital) signal are displayed on the screen by means of suitable multiplexing and synchronization electronics so that the processor managing the screen "sees" a cartesian display, but the cartesian display is periodically interrupted and the polar display is interjected and is displayed in a polar format.

Abstract: A method is disclosed for assigning radar recurrences to radials to be displayed.A converter has means receiving an antenna rotation signal (68 ) and a radar synchronization signal (SY.sub.R), and groups incident recurrences in radials to be displayed as follows:memorization of the incident radials at the rate of their arrival in one of the memories of a group of three with, as the case may be, grouping of the incident recurrence with the already memorized recurrence, with the number of memory being written in getting incremented by one unit at the first blip SY.sub.R following the reception of a blip .epsilon.; andreading of a memory during the reception of a blip .epsilon. in order to constitute a radial, the number of the memory to be read being obtained by deducting 1 from the number of memory being written in at this moment.

Abstract: A weather radar system having improved display characteristics for rotation and translation of weather data where the rotations and translations are accomplished by converting data in a dedicated polar coordinate memory to display memories. The translation and rotation of the data between data updates is accomplished by referring to the data stored in the dedicated polar coordinate memory and thereby generating new rotated or translated data without requiring a manipulation plate of the data in the display memories.

Abstract: A method and apparatus for converting polar format radar video data into a horizontal raster format output to a TV monitor. Radar video data comprises radar video pixels each having an associated intensity value and a polar coordinate in a raster display. The TV monitor includes a display screen including a plurality of pixels wherein each pixel has a corresponding X,Y address. The apparatus and method of the invention comprises steps or apparatus for storing the radar video pixels, translating X,Y addresses into corresponding angular and radial coordinates, scanning the storage means using the translated X,Y address and interpolating a radar intensity value for the translated X,Y address. The radar video pixels are indexed by radial and angular coordinates. The scanning process includes accessing at least four radar video pixels surrounding the translated X,Y address.

Abstract: A marine radar system having a multi-plane video memory for storing scan-to-scan integrated video data used to raster scan the CRT. A scan converter generates cartesian or x,y addresses for the video memory and synchronous with the generation of each, x,y address, generates a range address for reading corresponding video data from an r,.theta. or polar memory. The x,y addresses are generated along azimuth sweeps by incrementing one coordinate by a pixel unit and the other coordinate by a trigonometric function. The unit coordinate and the trigonometric function are determined by the 45.degree. octant in which the azimuth sweep is located. The pixel unit incremented coordinate is offset by one pixel unit from the origin of the azimuth sweep in alternate octants to address pixels along the octant boundaries and thereby avoid display artifacts.

Abstract: A radar system having a raster scan memory storing scan-to-scan integrated true motion stabilized data. A scan converter generates x,y addresses along azimuth sweeps from the x,y coordinates of own-ship relative to an arbitrary true reference origin. Accordingly, as own-ship moves, the initial x,y coordinates for the azimuth sweeps are continuously being updated. For each x,y coordinate generated, the scan converter also generates a range address for reading corresponding video data stored in polar coordinates relative to own-ship. The x,y coordinates are coupled to a PROM which rolls over the x,y coordinates that are outside of the x,y address field of the memory thereby enabling the addressing of the memory for storing data derived from corresponding polar coordinate video data. Data in the memory is used to raster scan a visual display. The memory is organized into a plurality of planes wherein the data for each pixel of the display is derived from a plurality of bits that are scan-to-scan integrated.

Abstract: An echo receiving system is provided for periodically scanning a region for echo returns obtained in polar coordinates and for providing a visual display of such received echo returns in a rectangular raster format, such system comprising: a scan converter, responsive to the echo returns obtained in polar coordinates for converting such returns into rectangular coordinates; and, means for modifying such coordinate converted returns and for displaying such modified, coordinate converted returns in the rectangular raster format with displayed data being a function of the scan-to-scan change in echo returns from objects in the second region. With such arrangment, target build-up and target decay may be presented in the digitally generated raster display in a manner similar to that presented in an analog PPI display.

Abstract: A surveillance radar system which has a display processor 1 that receives graphic data from a computer 4 which are edited and divided according to target data and console associated data or background information data and which is edited in two arithmetic logic units 2 and 3 and in response to a console request are combined after being edited and are supplied to output interfaces A, B, C and D and forwarded for transmission to picture screen consoles through refresher channels connected to the output interfaces. The invention is provided for the utilization in surveillance radar systems covering large areas and using a large number of picture screen console.

Abstract: The invention concerns a method for smoothing, through filling, an image generated by the conversion of polar coordinates into Cartesian coordinates. A filling of these pixels not involved in the conversion is performed at the level of the signal received in polar coordinates. Artificial radials are created between the effective radials supplied in polar coordinates and the artificial radials have attributed a non-zero video signal, as a function of the video signals of the adjacent effective radials. These artificial radials are thereafter converted into Cartesian coordinates and fill the pixels otherwise not involved. The invention has application to the digital scan converted for radar display.

Abstract: A method and a device for extending the range of radar video data (recurrences) received at the radar pulse repetition frequency (PRF) which can be accented by a digital image converter (DIC) for processing a radar-type image. The frequency of the angular increments (.epsilon.) received for locating the angular position (.theta.) of the radar antenna with respect to a reference direction (north) is modified in order to make the angular increment frequency more nearly a function PRF, thereby guarding against any irregularity of the radar image or any defect of remanence.

Abstract: In a scan converter for converting polar-coordinate radar data into a standard video display scanned at a 100 ns per pixel rate, the reading of sixteen x-y pixels into the video buffer, writing of two polar pixels into the x-y memory, and fading of four x-y pixels in the x-y memory can all be accomplished in a single 1600 ns time slot by using a nibble mode of addressing with an x-y memory made up of four standard 64K chips operable in parallel. In another aspect of the invention, radar data can be written into the x-y memory of a scan converter at double that rate without affecting the read or fade capabilities by configuring the x-y memory chips in such a manner that a given address on the memory chips represents a group of adjacent pixels of one line of the display and a corresponding group of pixels of the next adjacent line of the display.

Abstract: A system for converting A-scan signals in r, .theta. co-ordinates into display data for x, y co-ordinate display locations, in which, for each A-scan signal, signal values for which the r co-ordinate is greater than a predetermined value contribute to the display data and values for which the r co-ordinate is less do not, and the predetermined values of r are different for different A-scans. FIG. 2 shows pixels, or display locations, close to the origin of an x, y rastor display. The lines radiating from the origin show the r, .theta. co-ordinates of A-scan signals derived from a radar antenna, superposed for purposes of illustration on the grid of pixels. The display data used to brighten an individual pixel is taken only from some, and not from all, of the A-scans which intercept that pixel. In particular, no data is taken from the portions of the A-scans which lie radially inwardly of the points 28 to 36, but data is taken from the portions of the A-scans that lie radially outwardly.

Abstract: A method for optimizing the storage of video signals in a digital scan converter provided with an intermediate block memory provided between the radial memory and the image memory. In the block memory, the pixels to be displayed are grouped together in blocks, the blocks being transferred in parallel to the image memory when they are completely filled. The blocks of the block memory correspond to those of the image memory and can each be used several times during a single antenna revolution.

Abstract: A pulse radar apparatus is provided with a transmitter and receiver unit (1), a video extractor (2) connected thereto for obtaining digitized plotting data, a plot processor (3) for determining the track positions with the associated digital data from the plotting data obtained in consecutive antenna revolutions, and a display system (5) for presenting both the video signals from the transmitter and receiver unit (1) and the track positions with the associated digital data. The pulse radar apparatus is furthermore provided with a data converter (4) deriving video signals from the plotting data, which video signals, after mixing with the video signals from the transmitter and receiver unit (1) are presented on the display (5) on a real-time basis.

Abstract: A method and apparatus for processing ultrasonic echo signals employ intermediate storage and representation of the echo signals in the form of image vectors, such storage and representation proceeding independently of the scanning technique utilized to generate the image vectors, such that switching among various scanning techniques is permitted. The full length of each image vector is written into an image memory in column fashion, the stored vectors being read out as image signals in a format suitable for specific types of representation, such as on a television monitor, the format instructions being contained in a memory or generated by an arithmetic unit. Upon read out from the image memory, the geometric form of the ultrasonic scan is reconstructed in a position and form corresponding to the actual scan, and the ultrasonic echo signals are similarly represented at their true positions.

Abstract: Disclosed is a system for high speed conversion of radar formats from polar coordinates to cartesian coordinates. From an initial address X.sub.i Y.sub.i where a radar pulse crosses a display, subsequent addresses are determined by adding constant values sin .theta..sub.i and cos .theta..sub.i to X.sub.i and Y.sub.i. This is faster than the prior method of calculating x.sub.i and Y.sub.i by multiplying R.sub.i (range) by sin .theta..sub.i and cos .theta..sub.i. Also disclosed is a system for filling the display between adjacent radials at long ranges where spoking of the display tends to occur. This is done by adding constant increments to one cartesian value on one vector until the next vector is reached while maintaining the other cartesian value constant.

Abstract: An aircraft locating system identifies on a TV format radar display the position of a specific aircraft based on an RF transmission from the aircraft on an RF channel. The locating system includes at least a pair of receive stations located within several miles of an airport and separated by a base line which is in near proximity to at least one runway at the airport or a theoretical extension thereof. Each receive station includes a passive receiver for determining a bearing angle to a source of RF on the RF channel for generating a signal representative of the bearing angle.The locating system further includes a processor which is responsive to bearing angle signals derived from the receive stations for generating line count and line delay information. The line count and line delay information correlate a position determined by the bearing angle signals from at least a pair of receive stations with a frame of reference of the TV display.

Abstract: A digital scan converter comprises an A/D converter; an input buffer; a random access memory; a write address generator; a plurality of read address generators; an address switch circuit composed of a first address switch means for switching the addresses from the write address generator and the read address generators and delivering the addresses via an address signal line to the random access memory, and alternately switching a first address signal line for transmitting the address from the write address generator and a common signal line for commonly transmitting the addresses from the plurality of the read address generators for connecting one of said switched lines with the address signal line, and a second switch means for switching in succession the connection between the common signal line and a plurality of second signal lines respectively connected with the plurality of the read address generators for transmitting the addresses; a plurality of output buffer; an output switch circuit having a third s

Abstract: A method for processing video signals in a digital image transformer in which, before conversion of the video data of the radar from polar coordinates into cartesian coordinates to be displayed on a television monitor, the distance sampling frequency is phase-locked to the sync pulses of the radar and the number of converted radials is limited to the resolution of the coder while satisfactory persistance is ensured and conversion errors are eliminated.

Abstract: High-amplitude-resolution graphics for raster-scanned television systems are generated beginning with relatively low-amplitude-resolution sampled data from image memory affording spatial resolution approximately the same as that of the television signal, generally at least as large as that afforded by the number of lines per field and by the video bandwidth used in the television system. The sample-data raster scan used in the television system is converted to the coordinate system used for memory addressing. The whole-number portions of the memory address are used to access addressable sample data at points surrounding the point specified by the complete address including whole-number and fractional portions; and the fractional portions of the address are used to perform an interpolation between or among the accessed sample data.

Abstract: A 360.degree. IFF video resynchronizer unit for storing pertinent data such s the range, the code, the IFF mode and the azimuth for each reply from associated transponders is disclosed. The 360.degree. IFF video resynchronizer unit is also configured for interfacing with one of a plurality of interrogator subsystems associated with a plurality of radar systems having multiple antennas so as to backup any one of the plurality of interrogator subsystems with a single 360.degree. IFF video resynchronizer unit. In addition, any number of the plurality of interrogator subsystems can be replaced with a single 360.degree. IFF video resynchronizer unit when at least one of the plurality of interrogator subsystems is present.