ANTI-COLLISION VEHICULAR RADAR SYSTEM

• US 3,778,826 A
• Filed: 09/25/1972
• Issued: 12/11/1973
• Est. Priority Date: 12/30/1969
• Status: Expired due to Term

• Current Assignee: John B. Flannery, Paul D. Flannery
• Original Assignee: John B. Flannery, Paul D. Flannery
• Inventors: Flannery, John B., Flannery, Paul D.
• Primary Examiner(s): Tubbesing, T. H.
• Application Number:
  US05/291,567
• Time in Patent Office: 442 Days
• Field of Search: 343/7ED,8,112CA 333/11 180/98
• US Class Current: 342/71
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93185 Controlling the brakes
• CPC Class Codes: G01S 2013/9319 Controlling the accelerator
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles

Abstract

A simplified radar system mounted on a vehicle and having an unmodulated RF signal transmitter-receiver beamed along a path to reflect signals from any obstacle. A novel circuit including an assymmetrical magic tee; an opening and closing Doppler discriminator, a closing Doppler frequency sensing means, a transitory obstacle discriminator and an override means is arranged to control power means which pulses the brakes, when driver inattention, or fog, requires braking or turning in time to avoid collision. The system reacts only in emergency stop situations to avoid collision by substituting the relatively short reaction time of the Doppler sensing radar system for the relatively long reaction time of an operator and in being independent of all other parameters such as input from vehicle speedometer, distributor or the like.

Claims

1. A vehicular radar system for automatically decelerating or stopping a vehicle to avoid a collision with an obstacle in an emergency stop situation, said system comprising:

transmitter-receiver means mounted on said vehicle to beam an unmodulated, CW electro-magnetic signal along the path of said vehicle and to receive reflections of the transmitted signal from any obstaclE in said path;

means for detecting the Doppler signal caused by relative velocity between said vehicle and obstacle;

asymmetrical magic tee means for discriminating between such detected opening and closing Doppler signals and responding only to closing Doppler signals, automatic powered means actuated by electric signal means for decelerating or stopping said vehicle, and means responsive only to the frequency of said closing Doppler signals and independent of any other parameters for energizing said electric signal means at a frequency in direct proportion to the relative velocity of said vehicle and obstacle whereby a collision is avoided by substituting the relatively short reaction time of the Doppler sensing radar system for the relatively long reaction time of the operator.

2. A vehicular radar system as specified in claim 1 plus means responsive to said closing Doppler discrimination means for sensing a continuous train of cycles accumulating to a predetermined value, before energizing said electric signal means;

whereby non-dangerous, temporary obstacles, in the path of said vehicle, do not cause a braking response in said system.

3. A vehicular radar system as specified in claim 1 plus:

over-ride circuit means on said vehicle, including a switch proximate the accelerator pedal of said vehicle, actuation of said switch energizing said circuit means to disassociate said system from said automatic powered means and permit the operator to assume full control of said vehicle.

4. A vehicular radar system as specified in claim 1, wherein:

said asymmetrical magic tee means for discriminating between detected opening and closing Doppler signals includes an asymmetrical magic tee, separating the detected Doppler signal into two components having a phase shift other than 0* or 180* with respect to each other and changing the polarity of the phase relationship as a function of opening or closing Doppler, and includes a differentiating circuit for discriminating between said opening and closing Doppler.

5. A vehicular radar system as specified in claim 1, wherein:

said asymmetrical magic tee means for discriminating between detected opening and closing Doppler signals includes an asymmetrical magic tee, separating said signals into two components, with a predetermined abnormal phase shift, and switch means including a one-shot circuit including a transistor, said transistor becoming conductive to cause said one-shot circuit to fire only when closing Doppler exists.

6. A vehicular radar system as specified in claim 1, wherein:

said vehicle includes a brake pedal and an accelerator pedal, said automatic powered means includes a mechanical linkage between said pedals arranged to retract said accelerator pedal when said brake pedal is depressed and said electric signal means includes a series of electric pulses arranged to automatically depress said brake pedal at a rate which varies with vehicle speed.

7. In a vehicular radar system for actuation in emergency stop situations, the combination of:

automatic powered means, responsive to electric signal means, for decelerating a vehicle;

transmitter-receiver means mounted on said vehicle to transmit and receive unmodulated RF energy in a relatively small angular sector directly in front of the vehicle for reflection from an obstacle in said sector;

electronic means for sensing opening and closing Doppler in said reflections, and responding only to closing Doppler frequencies;

electronic means responsive to said closing Doppler frequencies for sensing true and false obstacles and responding to true obstacles, located in said path for a predetermined period, and electric signal means responsive only to closing Doppler frequencies, reflected from true obstacles for at least said predetermined time, and independent of any other parameters for repeatedly energizing said automatic powered deceleration Means in pulses at a frequency directly proportional to said closing Doppler frequencies and to the relative velocity between said vehicle and said obstacle whereby a collision is avoided by substituting the relatively short reaction time of the Doppler sensing radar system for the relatively long reaction time of the operator and actuation is not dependent on input from moving parts of the vehicle.

8. A vehicular radar system for screening out opening movements while sensing closing movements between a vehicle and an obstacle in the path thereof, said system comprising:

combined RF signal transmitter-receiver means on said vehicle for reflecting a signal from said obstacle, said means including Doppler detection means;

power actuated deceleration means on said vehicle controlled by electric signal means;

asymmetrical magic tee means for discriminating between opening and closing detected Doppler, frequencies in the reflections of said RF signal means, and for emitting electrical signals only when closing Doppler signals are so detected;

closure rate detection means for sensing the frequency of said detected closing Doppler signals and means responsive only to said closure rate detection means and independent of any other factors, for energizing said electric signal means in pulses directly proportional to the closing Doppler frequency so detected;

whereby said vehicle will be pulse decelerated at a frequency of pulsation depending only on its rate of approach toward said obstacle.

9. In a radar system of the type utilizing the Doppler effect:

asymmetrical magic tee means for discriminating between opening and closing Doppler in the detected audio frequencies said means comprising the generating of a unique phase relationship between two detected Doppler signals, the polarity of said phase relationship being dependent on the sign of the relative velocity, and means responsive only to closing Doppler signals so discriminated, and free of all other parameters, for energizing electric signal means in pulses directly proportional to the closing Doppler frequencies so detected.