Determination of wheel sensor position using radio frequency detectors in an automotive remote tire monitor system

Abstract

A tire monitor system and method rely on only two RF detector mounted on the vehicle, one in close proximity to one of the front wheels and the other in close proximity to one of the rear wheels. An RF detector can distinguish between its local transmitter and the other transmitter on the same axle by the amount of signal received. Every time the controller decodes transmitted RF data, the controller looks to see if and which RF detector has detected the transmission. The controller can then determine over a short period of time which sensor identifier belongs to which corner of the vehicle.

1 . A tire monitor method comprising: 
 at two or more detectors, detecting envelopes of respective radio transmissions from two or more tire monitors; and    based on the detected envelopes of the respective radio transmissions, identifying a source tire monitor position.    
     
     
         2 . The tire monitor method of  claim 1  further comprising: 
 based on the detected envelopes, modulating a wireline signal; and    identifying the source tire monitor position based on the modulated signal.    
     
     
         3 . The tire monitor method of  claim 1  further comprising: 
 based on the detected envelopes, determining a number of received transmissions from each of the two or more tire monitors; and    identifying the source tire monitor position based on the number of received transmissions.    
     
     
         4 . The tire monitor method of  claim 1  further comprising: 
 based on the detected envelopes, determining a rate of received transmissions from each of the two or more tire monitors; and    identifying the source tire monitor position based on the rate of received transmissions.    
     
     
         5 . The tire monitor method of  claim 1  further comprising: 
 detecting a signal envelope for the transmissions from a first tire monitor;    detecting a signal envelope for the transmissions from a second tire monitor; and    comparing the detected signal envelopes to determine the source tire monitor position.    
     
     
         6 . The tire monitor method of  claim 5  further comprising: 
 based on the detected envelopes, counting received transmissions from the first tire monitor;    based on the detected envelopes, counting received transmissions from the second tire monitor; and    comparing the transmission counts to determine source tire monitor position.    
     
     
         7 . The tire monitor method of  claim 1  wherein detecting envelopes comprises: 
 modulating a wireline signal to indicate detection of the envelopes of the respective radio transmissions.    
     
     
         8 . The tire monitor method of  claim 1  wherein detecting envelopes comprises: 
 in response to the respective radio transmissions, controlling actuation of a circuit element conducting a current which is detected to identify a position of a tire monitor transmitting the respective radio transmissions.    
     
     
         9 . A remote tire monitor system comprising: 
 a first plurality of tire monitors associated with wheels of a vehicle and configured for transmission of radio signals conveying information;    a second plurality of detectors, each detector associated with a pair of tire monitors to detect presence of radio signals from the pair of tire monitors and to produce a detected transmission indication in response to the detection of the presence of the radio signals; and    a control unit electrically coupled by conductors with the plurality of detectors to receive detected transmission indications, the control unit configured to receive tire monitor transmissions and associate transmitting tire monitors with positions on the vehicle based on the received detected transmission indications.    
     
     
         10 . The remote tire monitor system of  claim 9  wherein each detector of the second plurality of detectors comprises an envelope detector responsive to the presence of the radio signals to produce a wireline signal corresponding to an envelope of the radio signals.  
     
     
         11 . The remote tire monitor system of  claim 10  wherein the envelope detector modulates a current in a conductor electrically coupled with the control unit in response to the presence of the radio signals.  
     
     
         12 . A remote tire monitor system comprising: 
 tire monitors mountable on wheels of a vehicle and configured for radio transmissions of tire data;    radio detectors, each radio detector being configured to detect radio transmissions from tire monitors according to proximity to the tire monitors and produce an indication of a detected transmission, a first radio detector being positioned near one of a first pair of tire monitors and a second radio detector being positioned near a second pair of tire monitors on the vehicle, each radio detector being positioned proximate one tire monitor of its respective pair of tire monitors and positioned distal the other tire monitor of its respective pair of tire monitors; and    a control unit which receives the radio transmissions and which is coupled with the radio detectors to count the indications produced by respective tire monitors, the control unit determining respective positions of the tire monitors on the vehicle based on counts of the indications.