High resolution time-of-flight measurements
OwnerThomas Broussardinventor
Life of this patent
Estimating the term…
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.
Claims13
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.
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 said transmitter signal;
- c. at least one variable frequency oscillator for generating said transmitter signal, wherein the frequency of said variable frequency oscillator further comprise a frequency that is several times higher than the frequency of said transmitter signal;
- d. means for controlling (10) 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, wherein said phase relationship further comprise a transmitter phase signal (9) generated by said variable frequency oscillator, a receiver phase signal (14), and a phase shift circuit (8) for providing at least two selectable phase relationships between said transmitter and receiver phase signals;
- e. means for determining the frequency (19) of at least one variable frequency oscillator;
- f. at least one processor and control electronics (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.
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 said transmitter signal;
- c. at least one variable frequency oscillator having a frequency several times higher than the frequency of said transmitter signal for generating said transmitter signal;
- d. means for controlling (10) said variable frequency oscillator for providing an initial predetermined transmitter frequency and further controlling said variable frequency oscillator to phase lock said transmitter signal to the corresponding received signal to form a phase locked signal;
- e. means for measuring the frequency (19) of at least one variable frequency oscillator;
- f. timer circuit (37) for making coarse time-of-flight measurements;
- g. at least one processor (1) disposed for determining the integral number of cycles within the time-of-flight of said phase locked signal based on said coarse time measurements and said frequency measurements;
- and said processor using said integral number of cycles and said frequency measurements to make subsequent higher resolution measurement of 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 a target.
Dependencies are inferred from the claim text.