Collision avoidance system

• US 5,068,654 A
• Filed: 07/03/1989
• Issued: 11/26/1991
• Est. Priority Date: 07/03/1989
• Status: Expired due to Fees

• Current Assignee: Hazard Protection Systems Incorporated
• Original Assignee: Hazard Protection Systems Incorporated
• Inventors: Husher, Fredrick K.
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US07/374,841
• Time in Patent Office: 876 Days
• Field of Search: 340/903, 340/991-994, 340/988, 340/989, 340/435, 340/436, 340/505, 340/825.54, 340/825.69, 340/825.72, 340/825.06-825.14, 340/825.55, 455/11, 455/51, 455/53, 455/54, 455/56, 455/89, 180/167, 180/168, 375/107, 342/29-31, 342/41, 342/42, 342/455, 342/457
• US Class Current: 455/502
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26
• CPC Class Codes: G08G 1/161 Decentralised systems, e.g. inter-vehicle communication
• CPC Class Codes: H01Q 1/3233 particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems

Abstract

A collision avoidance system providing to each properly equipped vehicle an indication of the locational direction, heading, and relative velocity of other similarly equipped vehicles or stationary objects. Each vehicle in the system is equipped with a transponder module which transmits information data relating to that vehicle, and receives information data relating to the other similarly equipped vehicles. A central reference time signal transmitter is provided for transmitting a reference timing signal which effectively synchronizes each of the transponder modules. Upon receiving the reference timing signal, the transponder module subsequently transmits information data relating to that particular vehicle. Each of the transponder modules is allocated a unique time period for transmission of its information data. Thus, the system can accommodate a great number of transponder modules within the system, each transmitting their respective information data during unique time slots during a relatively small time frame.

Claims

1. A system which comprises:

transmitting means for continually transmitting a reference signal at a predetermined time interval;

a plurality of ground based transponder means for transmitting, in response to receipt of said reference signal, respective data signals at a common predetermined signal strength with horizontal polarization during different unique time periods following reception of said reference signal, each said transponder means being operative for receiving data signals transmitted by other transponder means in said system;

processor means coupled to each said transponder means for processing position status information including range information derived from signal strengths of said received data signals relative to said predetermined signal strength to provide about 10 feet of resolution at a range of 500 feet; and

indicating means coupled to each said processor means for indicating a collision threat to an operator based on said range information.

2. A collision avoidance system as claimed in claim 1, wherein said transmitted information data is shorter in duration than said specified time period so as to ensure transmission of said information data during only the specified time period designated for said object.

3. A collision avoidance system as claimed in claim 2, wherein said transmitting means comprises a multi-element antenna which transmits signals in an omni-directional manner.

4. A collision avoidance system as claimed in claim 2, wherein said receiving means comprises a multi-element antenna which receives signals in a uni-directional manner, said receiving means including a multiplexor for passing the signals received by each element of the antenna to said processing means in seriatim.

5. A collision avoidance system as claimed in claim 1, wherein said object is a vehicle and said other similarly equipped objects are moving vehicles or stationary objects.

6. A collision avoidance system as claimed in claim 1, wherein said object is a driverless vehicle having an inertial guidance system.

7. A collision avoidance system, comprising:

a central generator means for continuously and periodically generating and transmitting a reference signal along a transmission path;

receiving means associated with a ground based object for receiving said reference signal generated by said central generator means;

transmitting means associated with said ground based object for transmitting along said transmission path and in a specified time period after receipt of said reference signal a horizontally polarized signal containing information data relating to said ground based object in response to said receiving means receiving said reference signal, said receiving means also being operative for receiving information data transmitted by other similarly equipped ground based objects during different specified time periods after receipt of said reference signal;

processing means associated with said first mentioned ground based object for processing said received information data from said other similarly equipped ground based objects so as to derive the positional location of said other similarly equipped ground based objects with respect to said first mentioned ground based object with a resolution of about 10 feet at a range of 500 feet; and

indicating means associated with said first mentioned ground based object for indicating to an operator of said first mentioned ground based object a collision threat based on the positional location of said other similarly equipped ground based objects.

8. A collision avoidance system as claimed in claim 7, wherein said receiving means and said transmitting means are configured in a single housing so as to be vertically adjacent to one another.

9. A collision avoidance system as claimed in claim 7, wherein said processing means derives said positional location of said other similarly equipped objects according to signal strength of the received information data transmitted by the other similarly equipped objects.

10. A collision avoidance system as claimed in claim 9, wherein said positional location includes distance and direction of the other similarly equipped objects with respect to said object, said processing means further being operative for deriving relative velocities of said other similarly equipped objects from said received information data.

11. A collision avoidance system as claimed in claim 7, wherein said reference signal is an amplitude modulated signal and said information data is a frequency shift keyed signal.

12. A method of avoiding collisions, comprising the steps of:

continuously generating a reference signal through a transmission path at a predetermined cadence from a central location;

receiving said reference signal at a receiver unit associated with surface vehicle;

transmitting information data from a transmitter unit associated with said surface vehicle at a specified signal level through said transmission path in response to receiving said reference signal, said transmitting taking place during a unique time slot allocated for said surface vehicle after receipt of said reference signal;

receiving information data transmitted from other similarly equipped surface vehicles through said transmission path at said specific signal level during respective allocated unique time slots;

processing said received information data with a processor associated with said surface vehicle so as to derive range information relating to the location of said other surface vehicles based on received signal levels relative to said specified signal level with a resolution of about 10 feet at a range of 500 feet; and

indicating a collision threat to an operator of said surface vehicle by an indicator unit data based on said range information.