Radar signal selection based upon antenna bearing

• US 5,497,162 A
• Filed: 01/09/1995
• Issued: 03/05/1996
• Est. Priority Date: 01/09/1995
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Kaiser, Stephen G.
• Primary Examiner(s): ELDRED, JOHN W
• Application Number:
  US08/370,052
• Time in Patent Office: 421 Days
• Field of Search: 342/159, 342/59, 342/147
• US Class Current: 342/159
• CPC Class Codes: G01S 13/103 particularities of the measurement of the distance G01S13/12, G01S13/14, G01S13/16, G01S13/18 and G01S13/20 take precedence
• CPC Class Codes: G01S 13/106 using transmission of pulses having some particular characteristics G01S13/12, G01S13/22, G01S13/24, G01S13/26, G01S13/28 and G01S13/30 take precedence
• CPC Class Codes: G01S 13/325 using transmission of coded signals, e.g. P.S.K. signals
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9321 Velocity regulation, e.g. cruise control
• CPC Class Codes: G01S 2013/9325 for inter-vehicle distance regulation, e.g. navigating in platoons
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00
• CPC Class Codes: G01S 7/282 Transmitters
• CPC Class Codes: G01S 7/285 Receivers
• CPC Class Codes: G01S 7/36 Means for anti-jamming , e.g. ECCM, i.e. electronic counter-counter measures

Abstract

A method for mitigating interference among a plurality of radar sets utilizes the steps of: determining the direction in which a radar antenna is pointing; selecting one of a plurality of different non-interfering radar signals based upon the direction that the radar antenna is pointing, each different non-interfering radar signal beam dedicated to a particular direction of the radar antenna; and utilizing the selected radar signal. Radar antennae pointed toward one another do not interfere with one another since they are both using different non-interfering radar signals.

Claims

1. A method for mitigating interference among a plurality of radar sets, said method comprising the steps of:

a) determining the direction in which a directional radar antenna is pointing;

b) selecting one of a plurality of different non-interfering radar signals based upon the direction that the radar antenna is pointing, each different non-interfering radar signal being dedicated to a particular direction of the radar antenna; and

c) utilizing the selected radar signal;

d) wherein radar antennae pointed toward one another do not interfere with one another since they are both using different non-interfering radar signals.

2. The method as recited in claim 1 wherein the step of determining the direction in which the directional radar antenna is pointing comprises determining the compass bearing of the radar antenna.

3. The method as recited in claim 1 wherein the step of selecting a plurality of different non-interfering radar signals comprises selecting one of a plurality of orthogonal radar signals, the orthogonality being based upon at least one of:

a) sinusoidal carrier frequency;

b) pulse repetition frequency of a pulsed sinusoidal signal;

c) pseudo-random pulse repetition frequency coding of a pulse-sinusoidal signal;

d) pseudo-random phase coding of a sinusoidal signal;

e) pseudo-random frequency coding of a sinusoidal signal;

f) Walsh functions; and

g) cross-polarization.

4. The method as recited in claim 1 wherein non-interfering radar signals are assigned to directions such that radar signals for directions 180 degrees apart are optimally non-interfering.

5. A radar system for mitigating interference among a plurality of radar sets, each radar set comprising:

a) a directional antenna; and

b) a direction sensor for sensing the orientation of said antenna;

c) a signal selector for selecting one of a plurality of different non-interfering radar signals based upon the direction that the radar antenna is pointing, each different non-interfering radar signal being dedicated to a particular direction of the radar antenna; and

d) a radar transceiver for transmitting the selected radar signal through said direction antenna and for receiving the return radar signal through said directed antenna;

e) wherein two such radar antennae pointed toward one another do not interfere with one another since they are not pointed in the same direction and thus are both using different non-interfering radar signals.

6. The radar system as recited in claim 5, wherein said direction sensor is mechanically coupled to said directional antenna.

7. The radar system as recited in claim 5 wherein said direction sensor is configured to sense the compass bearing of said directional antenna.

8. The radar system as recited in claim 5 wherein said direction sensor comprises a compass.

9. The radar system as recited in claim 5 wherein said signal selector selects one of a plurality of orthogonal radar signals based upon at least one of:

a) sinusoidal carrier frequency;

b) pulse repetition frequency coding of a pulsed sinusoidal signal;

c) pseudo-random pulse repetition frequency coding of a pulsed-sinusoidal signal;

d) pseudo-random phase coding of a sinusoidal signal;

e) pseudo-random frequency coding of a sinusoidal signal;

f) Walsh functions; and

g) cross-polarization.

10. A radar set comprising:

a) a directional antenna;

b) an electronic compass coupled to said directional antenna for determining the compass bearing thereof;

c) a microprocessor responsive to said electronic compass for selecting one of a plurality of different orthogonal radar signals; and

d) an orthogonal waveform signal generator for generating the selected orthogonal radar signal;

e) a radar transceiver for transmitting and receiving the selected orthogonal radar signal via said directional antenna;

f) wherein two such radar antennae pointed toward one another do not interfere with one another since they are not pointed in the same direction and thus are both using different non-interfering radar signals.