Method and System for Determining the Delay of Digital Signals

Abstract

A method of and system for determining the time required for a digital bit or bit stream to traverse a round-trip path from a source transceiver to at least one destination transceiver and back is disclosed. The relative timing of the transmitted bit or bit stream is compared to the return bit or bit stream using a high speed comparison configuration so as to provide in substantially real-time various measurements related to or derived from the time required to traverse the round trip path, including distance measurement in indoor positioning, real-time locating, adaptive cruise control, intelligent transportation systems, robotics, collision avoidance, personnel accountability, emergency location, search and rescue, loss and theft prevention, logistics, marine safety, network analysis, communication channel characterization, and other high-speed measurement tasks. In addition, a method of and system for determining the distance between a source transceiver and a destination transceiver, and a method of and system for determining the angular position of a transceiver with respect to at least two other transceivers, are disclosed.

1 . A system for making a measurement of the amount of time required for at least one digital bit to traverse a round-trip path from a source transceiver to at least one destination transceiver and back, the system comprising:
 a high speed comparison configuration configured and arranged so as to (a) determine a measurement of the relative timing between a transmitted bit produced at a clock rate by the source transceiver and transmitted to a destination transceiver, and a corresponding return bit produced by the destination transceiver and received by the source transceiver in response to receiving the respective transmitted bit from the source transceiver, and (b) provide in substantially real-time at least one measurement related to or derived from a measurement of the time required for the transmitted and corresponding return bit to traverse the round trip path.   
   
   
       2 . A system for making a measurement of the amount of time required for a digital bit or bit stream to traverse a round-trip path from a source transceiver to at least one destination transceiver and back, the system comprising:
 a high speed comparison configuration configured and arranged so as to (a) determine a measurement of the relative timing between a transmitted bit or bit stream produced at a clock rate by the source transceiver and transmitted to a destination transceiver, and a return bit or bit stream produced by the destination transceiver and received by the source transceiver in response to receiving the transmitted bit or bit stream from the source transceiver, and (b) provide in substantially real-time at least one measurement related to or derived from a measurement of the time required to traverse the round trip path, wherein the high speed comparison configuration includes error correction configured and arranged so as to measure and correct for errors.   
   
   
       3 . A system according to  claim 2 , wherein error correction is configured and arranged so as to correct for one or more of the following: fixed delays and jitter. 
   
   
       4 . A system according to  claim 1 , further including a sampling configuration configured so as to sample each transmitted bit and the corresponding return bit at a multiple of the clock rate of the transmitted bit prior to comparing the relative timing of the two. 
   
   
       5 . A system according to  claim 1 , further including a processor configured and arranged so as to determine the distance between the source transceiver and the destination transceiver as a function of the time required to traverse the round trip path. 
   
   
       6 . A system according to  claim 1 , further including a processor configured and arranged so as to determine the two dimensional azimuth angle position of the source transceiver with respect to the destination transceiver and one other transceiver. 
   
   
       7 . A system for determining the distance between two transceivers in substantially real time using a measurement of the delay between (a) transmission at a clock rate of a transmitted digital signal by one of the transceivers functioning as a source transceiver and the other of the transceivers functioning as a destination transceiver and (b) reception of a return digital signal transmitted by the destination transceiver to the source transceiver in response to receiving the transmitted digital signal, the system comprising:
 the source and destination transceivers configured and arranged so as to define at least in part a round trip transmission path of the transmitted digital signal and the return digital signal:   the source transceiver including an oversampling component configured and arranged so as to oversample the return digital signal at an oversampling rate S so as to provide an oversampled return signal, wherein the oversampling rate S is a multiple of the clock rate of the transmitted digital signal;   a high speed comparison configuration configured and arranged so as to compare the transmitted digital signal to the oversampled return digital signal and generating at least two bytes of bits at the oversampling rate, wherein one of the bytes corresponds to a measurement of a differential time period during which a leading edge of the transmitted digital signal is transmitted and a leading edge of the return digital signal is received by the source transceiver, and the other of the bytes corresponds to a measurement of the differential time period during which a trailing edge of the transmitted digital signal is transmitted and a trailing edge of the returned signal is received by the source transceiver;   a value assignment component configured and arranged so as to assign a value to each of the bytes as a function of an ordering of the bits of each of the bytes, wherein the sequence of the least significant bit to most significant bit of one byte is temporally reversed; and   a delay determination component configured and arranged so as to determine the delay as a function of the assigned values of the two bytes.   
   
   
       8 . The system according to  claim 7 , further including a processor configured and arranged so as to accumulate a plurality of assigned values representing the delays for a plurality of transmitted and returned bits. 
   
   
       9 . The system according to  claim 7 , further including a noise compensation component configured and arranged so as to compensate for noise in the return digital signal. 
   
   
       10 . The system according to  claim 9 , wherein the noise compensation component is configured and arranged so as to compensate for an out-of-phase component of the noise. 
   
   
       11 . The system according to  claim 10 , wherein the noise compensation component is configured and arranged so as to determine an out-of-phase component as a function of the difference between a logical inverse of one of the bytes to a logical value of the other of the bytes. 
   
   
       12 . The system according to  claim 8 , further including a noise compensation component configured and arranged so as to compensate for noise in the return digital signal. 
   
   
       13 . The system according to  claim 12 , wherein the noise compensation component is configured and arranged so as to compensate for an out-of-phase component of the noise. 
   
   
       14 . The system according to  claim 13 , wherein the noise compensation component is configured and arranged so as to determine the out-of-phase component of noise as a function of the difference between a logical inverse of one of the bytes to a logical value of the other of the bytes.