US 2019/0107811 A1 · HIGH RESOLUTION TIME-OF-FLIGHT MEASUREMENTS

Abstract

This invention relates to apparatus and methods for measuring the time-of-flight of a signal. The signal may be acoustic energy or electromagnetic energy such as x-ray, radio frequency, microwave, millimeter-wave, radar, and laser. Unlike unambiguous ranging devices that measures the phases of two or more signals to determine the time-of-flight and requires long averaging to achieve some degree of accuracy, this invention phase lock one or more transmitter signals to the corresponding received signals in predetermined phase relationships and measures the frequencies of one or more variable frequency oscillators having frequencies several times higher than the frequency of the transmitter signal to determined the time-of-flight with much higher accuracy. An example of an embodiment of this invention is an apparatus that transmits a signal to a receiver and phase lock the transmitted signal to the received signal in a first selected phase relationship. A first frequency of the phase locked signal is determined and a second phase relationship that differs from the first phase relationship by a predetermined fraction of a cycle is selected. The transmitter signal relocks to the receiver signal in the second phase relationship and a second frequency of the relocked signal is determined. The time-of-flight is measured using the first and second frequencies and the predetermined fraction of a cycle difference in phase relationships.

Claims13

Dependent claims

A method for measuring the time-of-flight of a signal comprising:

a. transmitting transmitter signals (6) to a receiver (12), wherein the transmitter signals are generated by one or more high frequency variable frequency oscillators;
b. receiving and processing said transmitter signals;
c. controlling the frequencies of said frequency oscillators to phase lock the corresponding generated transmitter signal to the corresponding received signal to form at least first and second phase locked signals with frequencies that differ by a predetermined number of cycles within the time of flight;
d. making frequency measurements of said variable frequency oscillators for determining the frequency of said phase locked signals;
e. using said frequency measurements and said predetermined difference in number of cycles to measure at least one of a set of measurable factors from a group consisting of time-of-flight of said transmitter signal, velocity of said transmitter signal, range of a target, and velocity of said target.

2 more elements

Apparatus for measuring the time-of-flight of a signal comprising:

a. at least one transmitter (5) disposed to transmit a transmitter signal (6) to a receiver (12);
b. at least one receiver (12) disposed for receiving and processing the received signal (11) from said transmitter;
c. at least one variable frequency oscillator for generating at least one transmitter signal, wherein the frequency of said variable frequency oscillator further comprise frequencies that are several times higher than the frequency of said transmitter signal;
d. means for selecting and applying a drive signal (4) to said transmitter to transmit said transmitter signal to said receiver, wherein said drive signal is provided by said at lease one variable frequency oscillator;
e. means for receiving and processing said transmitter signal;
f. means for controlling said at least one variable frequency oscillator to phase lock said transmitter signal to the corresponding received signal in predetermined phase relationships to form at least first and second phase locked signals having frequencies that differ by a predetermined number of cycles within the time of flight;
g. measurement means to make frequency measurements of said at least one variable frequency oscillator;
h. at least one processor circuit and electrical signals (1) configured for processing said transmitter signals, and for measuring said time of flight based on said frequency measurements and said predetermined difference in number of cycles.

5 more elements

Dependencies are inferred from the claim text.

High resolution time-of-flight measurements

Life of this patent

High resolution time-of-flight measurements

Life of this patent

Abstract

Claims13