Abstract: A distancing system for determining a distance between first and second locations comprising mobile and fixed units. The mobile unit is arranged at the first location and comprises first receive and first transmit portions operating at respective first and second frequencies, first and second baseband processors operating based on first and second clock signals, and a first control portion. The fixed unit is arranged at the second location and comprises second receive and transmit portions operating at the respective second and first frequencies, a third baseband processor operating based on a third clock signal, a second control portion, and a mode switch. The configuration of mode switch circuit allows communication between the fixed and mobile units or a determination of the distance between first and second locations.

Abstract: A distancing system comprising radio frequency transceivers and data processing circuits. The radio frequency transceivers allow data transmission via a high frequency radio signal. The transmission and receipt of these radio signals can be timed to estimate distance. But the data processing circuits operate at local clock frequencies, and one cannot be sure at what point a give radio frequency signal was received to a resolution greater than one-half cycle of the local clock signal. The data processing circuits periodically "skip" to resynchronize with incoming data streams. These skips occur at intervals corresponding to the frequency difference between the local clock frequencies. This frequency difference can be used to pinpoint fairly precisely when a given radio frequency signal was received in a previous half-cycle of the local clock.