System and method for position determination by impulse radio using round trip time-of-flight

An impulse radio system, comprising:

• a first impulse radio transceiver including a clock, the clock configured to generate a first clock pulse, the first impulse radio being configured to transmit a first ultra wideband signal responsive to the first clock pulse;
• a second impulse radio transceiver spaced apart from the first impulse radio transceiver and configured to receive the first ultra wideband signal, the second impulse receiver being configured to transmit a second ultra wideband impulse signal responsive to the first ultra wideband signal;
• and
• wherein the first impulse radio transceiver is configured to receive the second ultra wideband signal, the clock being configured to generate a second clock pulse responsive to the second ultra wideband impulse signal, the first impulse transceiver being configured to determine an elapsed time between the first and second clock pulses indicative of a total time of flight of the first and second ultra wideband signals.

In an impulse radio system including a first impulse radio transceiver and a second impulse radio transceiver spaced from the first impulse radio transceiver, a method comprising:

• (a) transmitting from the first impulse radio transceiver a first ultra wideband signal;
• (b) receiving the first ultra wideband signal at the second impulse radio transceiver;
• (c) transmitting, from the second impulse radio transceiver, a second ultra wideband signal responsive to the first ultra wideband signal;
• (d) receiving the second ultra wideband signal at the first impulse radio transceiver;
• and
• (e) determining an elapsed time, between the transmission of the first ultra wideband signal and the reception of the second ultra wideband signal, indicative of a total time-of-flight of the first and second ultra wideband signals.

In an impulse radio system including a first impulse radio transceiver and a second impulse radio transceiver spaced a known distance from the first impulse radio transceiver, a method for calibrating distance measurements, comprising:

• (a) transmitting from the first impulse radio transceiver a first ultra wideband signal;
• (b) receiving the first ultra wideband signal at the second impulse radio transceiver;
• (c) transmitting, from the second impulse radio transceiver, a second ultra wideband signal in response to the first ultra wideband signal;
• (d) receiving the second ultra wideband signal at the first impulse radio transceiver;
• and
• (e) determining an elapsed time representing a time difference between the transmission of the first ultra wideband signal and the reception of the second ultra wideband signal;
• (e) producing an estimated delay representing a time difference between the reception of the first ultra wideband signal and the transmission of the second ultra wideband signal;
• (f) determining an estimated distance between the first and second impulse radio based on the elapsed time and the estimated delay;
• and
• (g) performing one of
• determining an error distance between the estimated distance and the known distance, and
• updating the estimated delay based on the known distance.

An impulse radio system, comprising:

• a first impulse radio transceiver configured to transmit a first ultra wideband signal;
• a second impulse radio transceiver spaced apart from the first impulse radio transceiver and not time synchronized with the first impulse radio transceiver, the second impulse radio transceiver being configured to receive the first ultra wideband signal, the second impulse radio being configured to transmit a second ultra wideband signal responsive to the first ultra wideband signal after a delay;
• and
• wherein the first impulse radio transceiver is configured to receive the second ultra wideband signal, the first impulse radio transceiver being configured to determine an elapsed time between the transmission of the first ultra wideband signal and the reception of the second ultra wideband signal, the first impulse radio transceiver being configured to determine a time difference between the elapsed time and the delay indicative of a total time-of-flight of the first and second ultra wideband signals.

In an impulse radio system including a first impulse radio transceiver and a second impulse radio transceiver spaced from the first impulse radio transceiver, a method comprising:

• (a) transmitting from the first impulse radio transceiver a first ultra wideband signal;
• (b) receiving the first ultra wideband signal at the second impulse radio transceiver;
• (c) transmitting, from the second impulse radio transceiver, a second ultra wideband signal;
• (d) receiving the second ultra wideband signal at the first impulse radio transceiver;
• (e) determining an elapsed time between the transmission of the first ultra wideband signal and the reception of the second ultra wideband signal;
• (f) determining a delay between the reception of the first ultra wideband signal and the transmission of the second ultra wideband signal;
• and
• (g) determining a difference between the elapsed time and the delay indicative of the total time-of-flight of the first and second ultra wideband signals.