Sunday, February 23, 2014

Patents related to RADAR PPI Display Technology

Patents related to RADAR PPI Display Technology
radar digital ppi range scale change - Google Search

Patent WO1981000022A1 - Ppi display for radar and synthetic symbology - Google Patents
Abstract
A complete frame of radar data is stored in real time in the memory (20) addressed by the converter (21) in accordance with antenna azimuth. PPI display (43) includes a rapid non-real radar time rotating scan by deflecting the beam along the azimuth sweeps thereof under control of X-rate and Y-rate signals provided for each sweep. Additionally, concatenated straight line strokes for synthetic symbology are displayed on the PPI display (43) under control of X-rate and Y-rate signals. The X-rate and Y-rate signals are applied sequentially to X and Y binary multipliers (49, 50) under control of the pattern memory (42) in order to generate clock signals at a frequency proportional to the rate signals. The clock signals are then applied to X and Y position counters (53, 54) respectively for generating the X and Y deflection signals via the digital-to analog converters (55, 57).


Patent EP2430472A1 - Combining data from multiple radar signals on a single plan position ... - Google Patents
Abstract  
In certain embodiments, a method for combining data from multiple radar signals on a single PPI includes receiving, from a first radar device having a first angular range of visibility, first radar signal data corresponding to the first angular range of visibility. The method further includes receiving, from a second radar device having a second angular range of visibility, second radar signal data corresponding to the second angular range of visibility. The method further includes performing compensation processing on at least a portion of the second radar signal data to form modified second radar signal data that is correlated to the first radar signal data. The method further includes combining at least a portion the first radar signal data with at least a portion of the modified second radar signal data to form combined radar signal data and generating, based on the combined radar signal data, a display on a radar PPI display.


Patent CA1057435A1 - Off-center radar display circuit - Google Patents
Abstract
In a radar PPI displays, digital techniques are utilized to allow an operator to move the point about which the radial trace beam rotates to a point remote from the center of the radar viewing screen and including movement off the screen without actually moving the display beam off the screen. A sweep signal generator detects the location of operator positioned off-center point from the setting of off-center control and is responsive to radar range scale and antenna position signals to generate appropriate ramp deflection sig-nals in the proper time sequence to accurately display a selected portion of the plan position indication upon the entire area of the viewing screen. A beam control circuit is responsive to the same signals as the signal generator and to a radar start pulse to determine the exact time the PPI display beam is to be turned on to display selected portions of the plan position indication. In this manner, the display beam is never deflected off the screen but is selectively blanked and unblanked and swept across the viewing screen to display the selected portion of the plan position indication upon the viewing screen as if the radar trace originated off the screen. The signal generator and control circuit cooperate such that when a target under study is in the middle of the screen when range scale is changed, the target will still be in the middle of the screen except that it will be expanded or contracted according to the range scale change.

Patent CA1136740A1 - Marine radar including anticollision unit - Google Patents

Abstract
Abstract A bright display radar system having anticollision capabilities in which received signals are digitized at a rate determined by a radar range setting and displayed at a constant relatively slow rate independent of the range setting. A computer based anticollision unit operates in response to the relatively slow digitized received signals so that targets may be tracked equally well at short and long ranges. Two sets of operator actuable switches are provided for controlling the anticollision unit. A first set of switches is provided which correspond directly to the most commonly used computer operating functions. The second includes an alphanumeric keyboard which may be used to actuate subroutines stored in a physically separate read-only memory which operates only in response to the alphanumeric keyboard.

Patent US3789403 - Digital line graphics control on range scalable radar crt display - Google Patents
Abstract
In a radar PPI display, the cathode-ray tube beam is intensified during a selected sweep in a predetermined pattern to generate an identifying pattern of line segments or dots on the sweep. The pattern is controlled by a range counter used to generate the sweep. Upon scaling the range, the clock pulse rate to the range counter is changed, thereby permitting the same stage, or stages, of the range counter to control intensification of the range sweep.

Patent WO2007035484A1 - Radar scan conversion for plan position indicator - Google Patents
Abstract
An angular scan interval may be divided into one or more sweep sectors for display. Polar (r, θ) coordinates may be calculated for rectangular (x, y) coordinates at each pixel of a display interval by computing polar (r, θ) coordinates in an interval of 0 to π/4 and by applying mapping equation sets. Bounds of a block of polar radar (R θ) coordinates that map to a given (x, y) coordinate may be computed. A mechanism to associate the bounds of the block in polar radar (R θ) coordinates and the rectangular (x, y) coordinates may be created. Bounds associated with the x-coordinate in a sweep sector may be calculated. A maximum of the x-coordinate bounds to xmax and a minimum to Xmin may be assigned accordingly. Bounds associated with the y-coordinate in the sweep sector may be calculated for each x-coordinate. A maximum of the bounds of the y-coordinate to ymax and a minimum to ymin may be assigned accordingly. Bounds of the block of polar radar (R θ) coordinates for each rectangular (x, y) coordinate computed from the mechanism may be retrieved. Radar observed parameter values scanned within the corresponding retrieved block bounds may be retrieved. Average or maximum parameter values within the block on the display may be displayed at the rectangular (x, y) coordinate.

Patent CA1199095A1 - Ppi to raster display scan converter - Google Patents
Abstract
PPI TO RASTER DISPLAY SCAN CONVERTER
Abstract A raster display apparatus for converting radar input data which is formatted to produce a Plan Position Indicator (PPI) presentation on a cursive display to a format which achieves a PPI type image on a raster display. The apparatus generates radar images on a raster display screen which appear as targets having continuous arcs of the proper length around the placement position of a radar. Average video levels within successive discrete fixed azimuthal standard angle increments are stored in a radial buffer memory for various increments of range. These video levels are used for all points within the presently active standard angular increment. Radial distance of a given image is computed for changes in orthogonal components such as X or Y using simple prestored sine and cosine functions. Conversion calculations comprise primarily additions using adders. The video amplitude of the image displayed is equal in amplitude to the video level of the input data stored in the radial video buffer memory for the standard angle being processed.
Processing of successive standard angle increments proceeds in approximate synchronism with the input data being provided in a cursive display format.

Patent US4224621 - PPI Display for radar and synthetic symbology - Google Patents
Abstract
A complete frame of radar data is stored in radar real time addressed in accordance with antenna azimuth. The PPI rotating display scan is generated by deflecting the beam along the azimuth sweeps thereof under control of X-rate and Y-rate signals provided for each sweep. The X-rate and Y-rate signals are applied sequentially to X and Y binary rate multipliers which generate clock signals at a frequency proportional to the rate signals. The clock signals are applied to X and Y position counters respectively for generating the X and Y deflection signals via digital-to-analog converters. Sequential application of the X and Y rate signals to the X and Y rate multipliers generates the rotating scan. The radar data stored in memory is accessed in accordance with the azimuth address in synchronism with the generation of the azimuth display sweeps. The stored data provides the video signal for the display tube so as to generate the radar display. The rotating scan is generated in non-real radar time at a rapid rate. X-rate and Y-rate signals are also applied to the binary rate multipliers for generating concatenated straight line strokes to display synthetic symbology. ΔX and ΔY signals are utilized to control the lengths of the strokes.

Patent US4224619 - Symbology writing apparatus for radar plan position indicator displays - Google Patents
Abstract
Symbology is written on a radar plan position indicator display with a rotating beam deflection field. The PPI radar range is quantized into range increments and digital data representative of the symbology to be written are inserted into a shift register which is clocked in synchronism with the range sweeps to provide interleaved digital data to the video input of the display. The normal radar video data is combined with the symbology data so that the symbology and normal radar returns are simultaneously written in real time. A portion of the symbology generating apparatus provides a manual acquisition marker comprising a range ring and an azimuth geometric figure. A range switch gates a clock pulse signal into a range up/down counter for incrementing and decrementing the number therein, the digital output of the counter being representative of the range of the range ring. The decoded digital output of the range counter is loaded into the shift register for bit serial application to the video input to the display. A manually operated azimuth switch similarly increments and decrements an azimuth counter, the digital output of which being compared to the radar antenna azimuth signal for positioning the azimuth geometric figure in azimuth. The symbology writing apparatus also includes a portion for providing alphanumeric or other localized symbology. These symbols are stored in a character table in the various orientations required for the plan position indicator display and written via the output shift register at azimuth and range coordinates provided by the system, the data therefor being interleaved with the data for the manual acquisition marker.
Patent US4206461 - Radar system with improved visual detection of long range targets - Google Patents
Abstract
A radar system in which the time duration of video pulses corresponding to echo returns is increased as a direct function of the range of the return. On a PPI visual indicator, the visibility of long range targets is thus enhanced by increased size without distorting the display of short range targets and clutter.

Patent US4663630 - PPI radar apparatus - Google Patents
Abstract
A PPI radar apparatus is constructed such that even when a transmission time cycle of radio waves is varied by switchover of a distance range to any of short, middle and long distance ranges, a sweep display time cycle of a radar video signal received in any of the distance ranges is maintained constant at all times; the sweep display time cycle is determined to meet the middle distance ranges, in the short distance ranges in which the reception time of radio waves is short, the video signals are written in storage means in real-time and then displayed by readout of the video signals at a low speed in synchronism with the sweep time cycle, in the long distance ranges in which the reception time of radio waves is long, the video signals are written in storage means in real-time and then displayed by a number of readouts in one sweep display time cycle; and the video signals written in a plurality of storage means are parallelly read out and a mean value or peak of the read-out video signals is obtained by arithmetic operation to thereby enhance the signal-to-noise ratio of the radar image.

Patent US4845501 - Radar video scan converter - Google Patents
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,θ 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 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.

Patent US4005415 - Automated radar data processing system - Google Patents
Abstract
An automated radar data processing system comprised of signal processing cuitry and programmed general purpose digital computer apparatus performs detection, classification and tracking of all targets within the field of view of the radar. The signal processing circuitry includes an adaptive video processor which receives the raw radar video signals and which derives a threshold from the noise, clutter, or electronic countermeasures signals in the immediate vicinity of the target and passes only those incoming signals which satisfy the detection criteria in terms of signal to noise ratio and extent. The signal processing circuitry is interactive with target track data derived and stored in the computer apparatus, so that the specific signal processing applied to any target by the adaptive video processor is optimized in accordance with the track status of that target. The proposed system also better enables a human operator to take a system management position wherein he can set up or establish data processing conditions so as, for example, to optimize target detection in highly variable or critical environments.

Patent US4754279 - Scan converter for radar - Google Patents
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.

Patent US4862154 - Image display processor for graphics workstation - Google Patents
Abstract
The present invention provides for the combining of image and graphics data in a high-performance raster graphics workstation. It allows the definition of windows on the screen, the dynamic control of the position of those windows, the magnification factor (integer zoom), and a color translation table, corresponding to each window. All these functions are under user control. Response time of 10 new frame buffers generated per second provides a "real" time response.
Patent US4873515 - Computer graphics pixel processing system - Google Patents
Abstract
A line-filtering antialiasing apparatus for a computer graphics display, with a set of parallel pixel processors functioning independently in a line drawing system and with plotting apparatus assigning individual pixels to the processors so as to track to the line. An optimum number of sixteen processors filter proximity data based on the vertical distance from a pixel center to the line center for shading pixels to gray-scale intensity in an area of influence four pixels wide. Line terminations are extended and shaded at the termination area. Pixel values for individual lines are summed to develop a total display image.

Patent US5315305 - Scan converter for a radar display - Google Patents
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.

Patent US5414429 - Device for converting output data of a radar for the display thereof on a ... - Google Patents
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 memory. The device includes an after glow processor connected to the interface, for controlling the contents of zones of videographic memory to produce an after glow phenomenon of certain points of the radar image.

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