Patent ID: 6078786
Filing Date: 2000-06-20
Classification: G01S

Abstract:
A method for measuring the distance between a first station and a second station using a communications channel over which synchronization bits and other useful data is sent comprising the steps of:transmitting a range request signal from said first station to said second station through said communications channel, wherein said range request signal is transmitted through said communications channel in the form of synchronization bit violations in which selected synchronization bits are replaced with the range request signal;measuring a first station processing time (T.sub.1);receiving said range request signal at said second station;formulating a range request answer at said second station and sending, again in the form of synchronization bit violations, that answer to said first station through said communications channel;measuring a processing time (T.sub.2) at said second station and sending said second station processing time to said first station through said communications channel;measuring at said first station the total cycle time (T.sub.cycle) between when said range request signal was initiated and when an answer from said second station was received at said first station;calculating the signal travel time (T.sub.R) between said first station and said second station by subtracting the first station processing time (T.sub.1) and second station processing time (T.sub.2) from the total cycle time (T.sub.cycle); and,calculating the distance by multiplying the travel time (T.sub.R) by the speed of the communication.