Polar coordinate format to a cartesian coordinate format scan converter

• US 4,002,827 A
• Filed: 05/15/1975
• Issued: 01/11/1977
• Est. Priority Date: 05/15/1975
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Nevin, Robert Leland, Cikotte, Leonard Joseph, O'Leary, John Joseph
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Coles, Edward L.
• Application Number:
  US05/577,971
• Time in Patent Office: 607 Days
• Field of Search: 343/5 SC, 178/7.5 R, 178/6.8, 178/7.30
• US Class Current: 342/185
• CPC Class Codes: G01S 7/298 Scan converters
• CPC Class Codes: G06F 7/548 Trigonometric functions; Co-ordinate transformations

Abstract

A slow scan radar signal is converted from a polar coordinate format to a cartesian coordinate format to permit the radar signal to be displayed on a television type display device. The radar signal, in analog form, is converted to a digital signal, placed in a memory to permit readout of the data in a cartesian coordinate format and converted from a digital to analog signal which may then be applied to the television type display device.

Claims

1. In a radar system including an angularly scanned antenna and an associated receiver system,

a scan converter for converting pulse-generated radar data received via said antenna -- receiver system in polar coordinate scan format to an x-y cartesian coordinate format comprising, in combination:

means for generating a cosine signal representative of the cosine of the antenna angle, said angle being defined by the angle between the polar coordinate radius along with said radar data is generated and a predetermined reference radius;

means operating in response to said cosine signal for generating a train of clock pulses for each radar pulse, the repetition rate of said pulses being a function of the cosine of said angle;

sampling means for generating a data signal representative of said radar in response to each of said clock pulses;

memory means having storage locations addressible in accordance with said x-y cartesian coordinate format;

means for loading said data signals into said memory means including a Y-address counter and means for incrementing said counter synchronism with said clock pulses, and

means for reading said data signals out of said memory in a sequence compatible with said cartesian coordinate format.

2. The scan converter set forth in claim 1 wherein said sampling means includes analog-to-digital converter means for generating said data signals in digital form and wherein said memory means includes means for storing digital signals.

3. In a radar system including an angularly scanned antenna and an associated receiver system;

a scan converter for converting pulse-generated radar data received via said antenna -- receiver system in polar coordinate scan format to an x-y cartesian coordinate format comprising, in combination;

means for generating a sine signal representative of the sine of the antenna angle, said angle being defined by the angle between the polar coordinate radius along with said radar data is generated and predetermined reference radius;

means operating in response to said sine signal for generating a train of clock pulses for each radar pulse, the repetition rate of said pulses being a function of the sine of said angle;

sampling means for generating a data signal representative of said radar in response to each of said clock pulses;

memory means having storage locations addressible in accordance with said X-Y cartesian cordinate format;

means for loading said data signals into said memory means including a X-address counter and means for incrementing said counter in synchronism with said clock pulses; and

means for reading said data signals out of said memory in a sequence compatible with said cartesian coordinate format.

4. The scan converter set forth in claim 3 wherein said sampling means includes analog-to-digital converter means for generating said data signals in digital form and wherein said memory means includes means for storing digital signals.