Vehicle proximity alarm system and method

Abstract

An object of the present invention is to provide a method of proximity detection based on transmitting at random intervals burst of a RF signal at a power level, and receiving, while not transmitting, a received RF signal. When detecting said received RF signal emitted by a target in range; an alarm signal is provided to warn of the proximity of the target. Another broad aspect of the invention is to deploy the above method among members of a territory and provide a monitoring patrol to verify if the proximity of those members can be detected from their RF signal. Another broad aspect of the invention is to provide to those members a plurality of status from which each member selects one corresponding to its current status and to transmit that status in the RF signal he is transmitting, thereby informing other members in range of his current status and enabling them to evaluate the potential danger associated with him.

1 - 39 . (canceled)  
     
     
         40 . A method of proximity detection, the method comprising: 
 transmitting at random intervals burst of a RF signal at a power level;    receiving, while not transmitting, a received RF signal;    detecting said received RF signal emitted by a target when in range; and    providing an alarm signal to warn of the proximity of said target.    
     
     
         41 . The claim as claimed in  claim 40 , wherein said RF signal comprises an RF frequency modulated signal in which is encoded information identifying the transmitter, and wherein said information is displayed.  
     
     
         42 . The claim as claimed in  claim 40 , wherein said RF signal comprises an RF frequency modulated signal in which is encoded information about the status of the transmitter, and wherein said alarm signal communicates the information about the status.  
     
     
         43 . The claim as claimed in  claim 40 , wherein said transmitting at random intervals burst a RF signal comprises transmitting alternately at two different power levels corresponding to a short range signal and to a long range signal.  
     
     
         44 . The claim as claimed in  claim 43 , wherein said providing an alarm signal comprises identifying said short or long range.  
     
     
         45 . The claim as claimed in  claim 43 , wherein said RF signal comprises an RF frequency modulated signal in which is encoded information about the signal power, and wherein said alarm signal identifies said corresponding short or long range.  
     
     
         46 . The claim as claimed in  claim 40 , wherein said burst of RF signal comprises burst duration of 20 ms, 1 to 3 mW of peak power, for an average transmitting power below 0.75 mW.  
     
     
         47 . The claim as claimed in  claim 40 , wherein said target comprises a vehicle.  
     
     
         48 . The claim as claimed in  claim 40 , wherein said target comprises a pedestrian.  
     
     
         49 . The claim as claimed in  claim 40 , wherein said RF signal comprises an omni-directional signal.  
     
     
         50 - 54 . (canceled)