Method and apparatus for determining location using phase difference of arrival

In an ultra-wideband (UWB) system comprising a UWB transmitter adapted to transmit a first signal in a first channel and a second signal in a second channel different from the first channel, and a UWB receiver having first and second antennae separated by a first distance, d, a method comprising the steps of:

• 1.1 using the first antenna to receive the first transmitted signal;
• 1.2 using the second antenna to receive the transmitted first signal;
• 1.3 using the receiver to:
• 1.3.1 develop a first range, r1, between the transmitter and a selected one the first and second antennas;
• 1.3.2 develop a first phase value as a function of the complex baseband impulse response of the first transmitted signal received by the first antenna;
• 1.3.3 develop a second phase value as a function of the complex baseband impulse response of the first transmitted signal received by the second antenna;
• 1.3.4 develop a first path difference value, p1, as a function of the first and second phase values;
• 1.4 using the first antenna to receive the second transmitted signal;
• 1.5 using the second antenna to receive the second transmitted signal;
• 1.6 using the receiver to:
• 1.6.1 develop a second range, r2, between the transmitter and a selected one the first and second antennas;
• 1.6.2 develop a third phase value as a function of the complex baseband impulse response of the second transmitted signal received by the first antenna;
• 1.6.3 develop a fourth phase value as a function of the complex baseband impulse response of the second transmitted signal received by the second antenna;
• 1.6.4 develop a second path difference value, p2, as a function of the third and fourth phase values;
• and
• 1.6.5 develop an (x,y) location of the transmitter relative to the receiver as a function of d, r1, p1, r2, and p2.