EP0068852A2
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A method and an apparatus for treating range and direction information data
Assignee: Kongsberg Gruppen ASA
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Filing: 1982-06-25
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Granted: —
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Expires: 2002-06-25
Abstract
Abstract Analog video information from a radar antenna rotating once each 2 seconds and emitting 2000 pulses per second is digitized by an A/D converter (15) which feeds a sweep memory (16) comprising 1024 range cells each storing one pixel. The analog antenna bearing 0 is digitized by a synchro/digital converter (19) and its sine and cosine fetched from a ROM table and supplied to X and Y rate multipliers (18) whose other input is a constant frequency. The pixels in the sweep memory (16) are written to X and Y coordinate addresses, determined from their range and bearing coordinates by the rate multipliers, in an intermediate storage block memory (17). Of the 4.096.000 pixels per antenna rotation, a central processor unit (20), operating in accordance with an algorithm, writes only 1048576 final pixels, four at a time, to a radar display refresh memory (3, 21) from which these pixels, in cartesian coordinate format, are transferred in page mode through a line buffer (30) to a D/A video output unit (5) and thence to a monitor (4) which provides a raster scan display of 1024 x 1024 pixels corresponding to the PPI information produced by the antenna. In controlling the transfer of pixels from the block memory (17) to the radar display refresh memory (3, 21), the central processor unit (20) forms and uses a table of memory block addresses associated with 4096 possible antenna bearing values, each memory block occurring once only in the table.
Inventors
- 👤 Magne Fossan
- 👤 Freddy Pohner
- 👤 Ole Johan Abelsen
- 👤 Tor Arne Torkilseng
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 05:10
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01S7/295; G01S7/298; G01S7/04; G01S7/06; G01S7/10
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
254 words
A method of treating range and direction information data which is converted from first scan format to a different scan format and is displayed on a raster scan display, wherein the range and direction information data provided by a range and direction sensor is stored in an input buffer as quantized video signals at addresses corresponding to the first format according to which the field of view, determined by the sensor in azimuth and range coordinates, is scanned at a given first rate, and addresses are generated as a function of the scan pattern and the scanning rate to accommodate the data read from the input buffer in a memory unit at locations corresponding to the display line pattern to be realized on the raster scan display, the data stored in the memory unit being transferred to a video output unit under the control of a timing unit so as to be presented on the raster scan display at a given second rate, characterized in that the storing of the data having converted addresses (X,Y) takes place in an intermediate storage unit (17) consisting of a number of square memory blocks (Bl B2) each corresponding to a plurality of pixels, that the intermediately stored data in the said blocks is transferred to a display memory (21) which comprises at least a sensor information refresh memory, after a writing sweep has passed respective memory blocks, and that in the said transfer of data to the display memory a plurality of pixels are transferred in parallel.
Claim 2
Independent Claim
254 words
A method of treating range and direction information data which is converted from first scan format to a different scan format and is displayed on a raster scan display, wherein the range and direction information data provided by a range and direction sensor is stored in an input buffer as quantized video signals at addresses corresponding to the first format according to which the field of view, determined by the sensor in azimuth and range coordinates, is scanned at a given first rate, and addresses are generated as a function of the scan pattern and the scanning rate to accommodate the data read from the input buffer in a memory unit at locations corresponding to the display line pattern to be realized on the raster scan display, the data stored in the memory unit being transferred to a video output unit under the control of a timing unit so as to be presented on the raster scan display at a given second rate, characterized in that the storing of the data having converted addresses (X,Y) takes place in an intermediate storage unit (17) consisting of a number of square memory blocks (Bl B2) each corresponding to a plurality of pixels, that the intermediately stored data in the said blocks is transferred to a display memory (21) which comprises at least a sensor information refresh memory, after a writing sweep has passed respective memory blocks, and that in the said transfer of data to the display memory a plurality of pixels are transferred in parallel.
Claim 3
Dependent Claim
153 words
A method as claimed in claim 1, characterized in that a writing sweep beam in effect sweeps across a region of the intermediate storage corresponding to the area being scanned by the sensor so as to simultaneously cover a number of memory blocks and consequently a number of pixel locations associated therewith and that the pixel locations which are covered by the writing sweep beam are filled thereby with data representing raw video information, the memory blocks containing the said filled pixel locations being arranged to displaceably overlap the writing sweep beam through its operation, and the memory blocks which are in the process of being filled being maintained stationary relative to the writing sweep beam whereas the blocks which have been passed by the writing sweep beam are emptied to the said refresh memory and displaced to a position ahead of the writing sweep beam so as to maintain the overlapping thereof.
Claim 4
Dependent Claim
36 words
A method as claimed in claim 1, characterized in that the number of memory blocks of the intermediate storage unit is large enough for all writing positions of the writing sweep beam to be covered thereby.
Claim 5
Dependent Claim
55 words
A method as claimed in claim 1, characterized in that the said quantized video signals are stored in a sweep memory from which the video information is transferred to the intermediate storage unit, a conversion from the first scan format to the second scan format being performed during said transfer and implemented by rate multipliers.
Claim 6
Dependent Claim
75 words
A method as claimed in claim 4, characterized in that the conversion from polar coordinates to cartesian coordinates by rate multipliers is accomplished by representing a range and direction vector associated with the sensor by a constant frequency, and generating its cartesian components X and Y as fractions of the said frequency by means of the rate multipliers, the fractions representing the corresponding sine and cosine values, respectively which are read from a read-only-memory table.
Claim 7
Dependent Claim
54 words
A method as claimed in claim 5, characterized in that the three frequencies (R,X,Y) are supplied respectively to a vector counter pointing to addresses in the sweep memory, and an X counter and a Y counter pointing to addresses in a block memory and a block pointer memory constituted by the intermediate storage unit.
Claim 8
Dependent Claim
99 words
A method as claimed in claim 6, characterized in that the data representing a picture line which is to be displayed on a raster scan monitor, is transferred from the refresh memory to a line buffer during the line flyback period of the display beam of the monitor and that during the total active horizontal line time of the monitor the pixels for the actual line are shifted from the line buffer to the monitor, the refresh memory during the horizontal line time being enabled for external input of fresh data which is to be displayed on the monitor.
Claim 9
Dependent Claim
66 words
A method as claimed in claim 7, characterized in that data from the refresh memory to the line buffer is transferred in groups, each group being selected so as to have the same row address so as thereby to reduce the access time to each address location by reading data in page mode and speeding up retrieval time and transfer time during the line flyback period.
Claim 10
Dependent Claim
135 words
Apparatus for carrying out a method for treating range and direction information data which is converted from a first scan format to a different scan format and is displayed on a raster scan display, as claimed in claim 1, characterized in that the apparatus comprises an intermediate storage unit (17) for storing the range and direction data having converted addresses (X, Y) and consisting of a number of square memory blocks (B1,B2) each corresponding to a plurality of pixels, the intermediate storage unit (17) being adapted to transfer the intermediately stored data in the said blocks (Bl, B2) to a display memory (21) which comprises at least a sensor information refresh memory (3), after a writing sweep has passed respective blocks, a plurality of pixels being transferred in parallel in the said transfer of data.
Claim 11
Dependent Claim
123 words
Apparatus as claimed in claim 9, characterized in that the intermediate storage unit comprises a dynamic block memory (17) the memory blocks of which are so controlled as to overlap a writing sweep beam (16b) through its writing operation, so that memory blocks (B4, B5, B2, B3) which are in the process of being filled with data are maintained with the same address location relative to the writing sweep beam (16b) for the covering thereof, whereas the blocks (Bl) which have been passed by the writing sweep beam are emptied to the said refresh memory and given another address so as to simulate a displacement to a position (B6) ahead of the writing sweep beam (16b), so as to maintain the overlapping thereof.
Claim 12
Dependent Claim
32 words
Apparatus as claimed in claim 9, characterized in that the number of memory blocks in the intermediate storage unit is large enough to cover all writing positions of the writing sweep beam.
Claim 13
Dependent Claim
46 words
Apparatus as claimed in claim 9, characterized in that rate multipliers (25,26) are provided for converting the coordinates of the quantized video data when the quantized video data is transferred by a sweep memory (16) to a block memory (17) constituted by the intermediate storage unit.
Claim 14
Dependent Claim
95 words
Apparatus as claimed in claim 12, characterized in that means are provided for generating a constant frequency representing a range and direction vector associated with the sensor, the said constant frequency being supplied as an input to the rate multipliers and the frequencies outputted from the rate multipliers (25, 26) being applied to drive respective counters, (27, 28), which point to addresses in the block memory (17), the constant frequency representing the vector also being applied to drive a specific counter (29) which through the sweep memory (16) is connected to the block memory (17).
Claim 15
Dependent Claim
70 words
Apparatus as claimed in claim 13, characterized in that the display memory (21) includes a line buffer (30) which receives from the said refresh memory (3) data representing a picture line of a monitor (4) on which the converted range and direction data is to be displayed, transfer of the said picture line data being effected during the line flyback period (thb) of the display beam of the monitor (4).
Claim 16
Dependent Claim
84 words
Apparatus as claimed in claim 14, characterized in that a selection means (31) is connected to the refresh memory (3) and the line buffer (30) to control transfer of data from the refresh memory (3) to the line buffer (30) in groups, each group being selected so as to have the same row address, thereby to reduce the access time to each address location by reading the data in page mode and speeding up retrieval and transfer time during the said line flyback period.
References Cited (Backward Citations)
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