Patent ID: 7135963

Claim:
A process for locating a tag for a hands-free system of a motor vehicle comprising the steps of: in a system comprising a tag ( 100 ), a first group of vehicle antennas defining a first antenna coverage zone, a second group of vehicle antennas defining a second antenna coverage zone, and a third antenna coverage zone defined by overlapping portions of the first and second antenna coverage zones, transmitting, from the first group of antennas to the tag, a first inquiry signal ( 14 ); transmitting, from the tag to the first group of antennas, a first response ( 16 ) to the first inquiry signal, and storing within the tag, for only a predetermined time span (T), a record of the first response; transmitting, from second group of antennas to the tag, a second inquiry signal ( 18 ); transmitting, from the tag to the second group of antennas, i) a second response ( 20 ) to the second inquiry, the second response including the stored record of the first response when an elapsed time period from transmitting the first response to transmitting the second response is less than the predetermined time span (T) and the second response being free of the stored record of the first response when the elapsed time period from transmitting the first response to transmitting the second response is not less than the predetermined time span (T); and determining a location of the tag to be i) in the first antenna coverage zone when the first response ( 16 ) is received by the first group of antennas, ii) in the second antenna coverage zone when the second response ( 20 ) is received by the second group of antennas, and iii) in the third antenna coverage zone when the second response is received by the second antennas and the second response comprises the stored record of the first response.