System and method for radar-vision for vehicles in traffic

• US 5,657,021 A
• Filed: 01/26/1995
• Issued: 08/12/1997
• Est. Priority Date: 06/30/1994
• Status: Expired due to Term

• Current Assignee: Ehsani Engineering Enterprises Incorporated
• Original Assignee: Ehsani Engineering Enterprises Incorporated
• Inventors: Ehsani-Nategh, Shahmir S., Ehsani-Nategh, Shahrokh
• Primary Examiner(s): Carone, Michael J.
• Assistant Examiner(s): MONTGOMERY, CHRISTOPHER KEITH
• Application Number:
  US08/378,466
• Time in Patent Office: 929 Days
• Field of Search: 342/70-72, 342/189
• US Class Current: 342/70
• CPC Class Codes: G01S 13/325 using transmission of coded signals, e.g. P.S.K. signals
• CPC Class Codes: G01S 13/426 Scanning radar, e.g. 3D radar G01S13/66 takes precedence
• CPC Class Codes: G01S 13/536 using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/0245 Radar with phased array antenna
• CPC Class Codes: G01S 2013/93272 in the back of the vehicles
• CPC Class Codes: G01S 2013/93276 in the windshield area
• CPC Class Codes: G01S 2013/9329 cooperating with reflectors or transponders
• 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 7/0234 Avoidance by code multiplex
• CPC Class Codes: G01S 7/038 Feedthrough nulling circuits
• CPC Class Codes: G01S 7/42 Diversity systems specially adapted for radar

Abstract

A plurality of substantially interference-free radar systems, each comprising: means for generating pseudorandom waveforms for sequential transmission by radar; and a radar transmitting and receiving phased array antenna having a horizontal beamangle of a few milli-radians (mR), and a vertical beamangle of about 25 mR.

Claims

1. A method for sensing mobile vehicles, comprising the steps of:

(a) transmitting by radar sequential pseudorandom code waveforms;

(b) tapping the pseudorandom code waveform transmitted in (a) and adjustably attenuating the tapped waveform to provide an attenuated version of the tapped waveform for cancellation of leakage of transmitted waveforms to a predetermined threshold;

(c) receiving echoes of the transmitted waveforms and subtracting therefrom the attenuated version of the pseudorandom code waveform obtained in step (b);

(d) correlating the attenuated versions of transmitted waveforms with waveforms resulting from subtraction in step (c); and

(e) recognizing an echo only when an output of the correlation in step (d) exceeds the predetermined threshold.

2. The method as defined in claim 1, step (a) further comprising the step of generating a radar beam having a horizontal beamangle of a few milli-radians.

3. The method as defined in claim 2, step (a) further comprising the step of sweeping the radar beam across a horizontal angle at least a few times the horizontal beamangle.

4. A radar vision system for a mobile vehicle according to the method of claim 2 and comprising radar reflectors marking road boundaries, and the radar beam angle of the few milli-radians continuously sweeping horizontally in front of the vehicle, when moving, between the road boundaries.

5. The method as defined in claim 1, wherein said attenuated version of the pseudorandom code waveform is adjusted in level in response to the integrated output of the correlation in step (d).

6. The method as defined in claim 5, wherein said level is adjusted at least once per hour of operation.

7. The method as defined in claim 3, for providing radar-vision to operators of mobile vehicles.

8. A plurality of substantially interference-free radar systems, each comprising:

means for generating pseudorandom waveforms for sequential transmission by radar;

means for tapping the pseudorandom waveform generated and transmitted;

means for adjustably attenuating the tapped waveform to provide an attenuated version of the tapped waveform for cancellation of leakage of transmitted waveforms to a predetermined threshold;

means for correlating said adjustably attenuated versions of said pseudorandom waveforms with received echoes thereof wherein the adjustably attenuated versions are subtracted from said received echoes before correlation; and

a radar transmitting and received phased array antenna having a horizontal beam angle of a few milli-radians.