Patent ID: 7636062

Claim:
A location system and a portable location device, the portable location device comprising: a first transmitter arranged to transmit ultra-wideband signals to the location system; a receiver for receiving the non-ultra-wideband control signals from the location system; and a control unit coupled to the receiver and arranged to control the transmission by the first transmitter of ultra-wideband signals in dependence on the non-ultra-wideband control signals received at the portable location device; and the location system comprising: a plurality of receivers for receiving the ultra-wideband signals from the portable device; a second transmitter arranged to transmit the non-ultra-wideband control signals to the portable device; and a location unit configured to determine the location of the portable location device by controlling the second transmitter to transmit the non-ultra-wideband control signals to the portable device and by using information derived from the ultra-wideband signals received from the first transmitter of the portable location device at more than one of the receivers of the location system.