High-resolution, active reflector radio frequency ranging system

摘要

A radio frequency ranging system is grounded in establishing and maintaining phase and frequency coherency of signals received by a slave unit from a master unit and retransmitted to the master unit by the slave unit. For a preferred embodiment of the invention, coherency is established through the use of a delta-sigma phase-lock loop, and maintained through the use, on both master and slave units, of thermally-insulated reference oscillators, which are highly stable over the short periods of time during which communications occur. A phase relationship counter is employed to keep track of the fractional time frames of the phase-lock loop as a function of the reference oscillator, thereby providing absolute phase information for an incoming burst on any channel, thereby enabling the system to almost instantaneously establish or reestablish the phase relationship of the local oscillator so that it synchronized with the reference oscillator.

主权项

1. A ranging system for determining a ranging measurement, the ranging system comprising:
a first unit that transmits at least one signal on at least one carrier asking for the ranging measurement, the at least one signal including at least one read range data packet; a second unit that receives the at least one signal, wherein the second unit achieves commonality of three frequencies and phase coherence with the at least one signal, the second unit including:
a first oscillator used in receiving the at least one signal and transmitting at least one second signal back to the second unit;a reference oscillator that controls the first oscillator, wherein the at least one read range data packet is used to achieve the commonality of three frequencies and phase coherence in the reference oscillator; anda phase coherency counter, wherein the phase coherency counter enables the second unit to transmit the at least one second signal back to the first unit with a predictable phase; and wherein the first unit receives the at least one second signal and determines the ranging measurement between the first unit and the second unit.