초록 ▼

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 circuit

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. Distances can thus be calculated based on a coarse timing value generated based on the local clock of one of the distancing units and first and second fine timing values generated based on the skips at one or both of the distancing units.

대표청구항 ▼

[ What is claimed is:] [1.] A system for determining the distance between a first location and a second location, the system comprising:a first distancing unit located adjacent to the first location, the first distancing unit comprisinga first radio frequency transceiver for transmitting a first sen

[ What is claimed is:] [1.] A system for determining the distance between a first location and a second location, the system comprising:a first distancing unit located adjacent to the first location, the first distancing unit comprisinga first radio frequency transceiver for transmitting a first send data stream as a first send radio frequency signal and generating a first receive data stream from a first receive radio frequency signal, anda first baseband processor circuit that operates based on a first clock signal having a first clock frequency, where the first receive data stream is asynchronous relative to the first clock signal and the first baseband processor circuit comprisesmeans for generating a first data receive signal indicating when the first receive radio frequency signal is received by the first radio frequency transceiver based on the first receive data stream and the first clock signal,means for adjusting the first receive data stream in time when the first receive data stream becomes out of synchrony with the first clock signal by a predetermined amount,means for generating a first skip signal whenever the first receive data stream is adjusted in time;a second distancing unit located adjacent to the second location, the second distancing unit comprisinga second radio frequency transceiver for transmitting a second send data stream as a second send radio frequency signal and generating a second receive data stream from a second receive radio frequency signal, anda second baseband processor circuit that operates based on a second clock signal having a second clock frequency, where the second receive data stream is asynchronous relative to the second clock signal and the second baseband processor circuit comprisesmeans for generating a second data receive signal indicating when the second receive radio frequency signal is received by the second radio frequency transceiver based on the second receive data stream and the second clock signal,means for adjusting the second receive data stream in time when the second receive data stream becomes out of synchrony with the second clock signal by a predetermined amount,means for generating a second skip signal whenever the second receive data stream is adjusted in time;first control means for operating the first distancing unit to transmit the first send radio frequency signal to the second distancing unit;second control means for operating the second distancing unit in response to the first send radio frequency signal to transmit the second send radio frequency signal to the first distancing unit;coarse timing means for generating a course timing value based on the first data transmit signal and the first data receive signal;first fine timing means for generating a first fine timing value based on a plurality of first skip signals; anddistance calculating means for calculating a distance value based on the coarse timing value and the first fine timing value.