| 摘要 |
A method for improving a radio location system based on time-of-arrival. Time-of-arrival radio location systems are limited in ultimate accuracy by signal-to-noise ratio and by the time varying multipath environment in which they must operate. These systems time stamp some feature of an arriving signal, from a transmitter, in order to calculate a range or a hyperbolic line-of-position. Some feature of the received signal must be identified which can provide repeatable readings, in order for a time-of-arrival system to be reliable. The present invention teaches techniques which maintain a high signal-to-noise ratio while identifying a feature of the received signal which is least affected by multipath. The technique uses correlation peak/envelope information to estimate the leading edge of the correlation function, then enhances discrete samples at the leading edge of the correlation function to yield high signal-to-noise ratio readings. The present invention can reduce required transmitted bandwidth, increase system resolution and accuracy by twenty to one, and maintain high message traffic throughput.
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