System and method for determining angle of arrival for communications

Patent metadata

Field	Value
Publication number	US-11269044-B2
Application number	US-202016795855-A
Country	US
Kind code	B2
Filing date	Feb 20, 2020
Priority date	Feb 20, 2019
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

A system and method for determining an Angle of Arrival (AOA) for frequency modulated communications. The system may include first and second antennas spaced apart from each other by a distance, and configured to receive wireless communications in the form of a frequency modulated signal. The system may determine a phase difference between the received signals irrespective of the modulations in the signal, thereby facilitating determining an AOA.

First claim

The invention claimed is:

1. A system for determining an angle of arrival for frequency modulated communications, said system comprising:
a first antenna capable of wirelessly receiving the frequency modulated communications to generate a first frequency modulated output;
a second antenna separated by a distance from the first antenna, the second antenna capable of wirelessly receiving the frequency modulated communications to generate a second frequency modulated output, wherein the first frequency modulated output and the second frequency modulated output are indicative of the frequency modulated communications arriving at the first and second antennas at different times;
a controller configured to determine a phase difference between the first and second frequency modulated outputs received by the first and second antennas, wherein the phase difference is determined based on unmodulated forms determined from the first and second frequency modulated outputs, whereby the phase difference is determined irrespective of frequency modulations in the first and second frequency modulated outputs;
a first receiver is coupled to the first antenna to generate the first frequency modulated output;
a second receiver is coupled to the second antenna to generate the second frequency modulated output;
the first and second frequency modulated outputs are generated simultaneously by the first and second receivers;
the phase difference is determined based on the first and second frequency modulated outputs;
the first receiver includes a first frequency mixer and the second receiver includes a second frequency mixer;
the first frequency mixer and the second frequency mixer are coupled to an oscillation output from a common oscillator;
the first frequency mixer generates a first intermediate frequency signal based on the first frequency modulated output from the first antenna and the oscillation output;
the second frequency mixer generates a second intermediate frequency signal based on the second frequency modulated output from the second antenna and the oscillation output; and
the phase difference is determined based on the first and second intermediate frequency signals.

2. The system of claim 1 wherein the angle of arrival for the frequency modulated communications is determined based on the phase difference.

3. The system of claim 1 wherein the first and second receivers are phase locked.

4. The system of claim 1 wherein:
the first and second antennas are operably coupled to a receiver;
the receiver generates a first received signal corresponding to the first frequency modulated output for a first duration, the first received signal being indicative of frequency modulations in the frequency modulated communications; and
the receiver generates a second received signal corresponding to the second frequency modulated output for a second duration, the second received signal being indicative of the frequency modulations in the frequency modulated communications, the first duration being different from the second duration.

5. The system of claim 4 comprising demodulation circuitry configured to generate a first unmodulated signal based on the first received signal and a second unmodulated signal based on the second received signal, wherein the first unmodulated signal corresponds to the first duration and the second unmodulated signal corresponds to the second duration.

6. The system of claim 5 wherein a first phase of the first unmodulated signal is compared to a second phase of the second unmodulated signal, and wherein the phase difference is based on a comparison between the first phase and the second phase with respect to unmodulated signals obtained at different times and generated from the frequency modulated communications.

7. A system for determining an angle of arrival for frequency modulated communications, said system comprising:
a first antenna capable of wirelessly receiving the frequency modulated communications to generate a first frequency modulated output;
a second antenna separated by a distance from the first antenna, the second antenna capable of wirelessly receiving the frequency modulated communications to generate a second frequency modulated output, wherein the first frequency modulated output and the second frequency modulated output are indicative of the frequency modulated communications arriving at the first and second antennas at different times;
a controller configured to determine a phase difference between the first and second frequency modulated outputs received by the first and second antennas, wherein the phase difference is determined based on unmodulated forms determined from the first and second frequency modulated outputs, whereby the phase difference is determined irrespective of frequency modulations in the first and second frequency modulated outputs;
wherein the first and second antennas are operably coupled to a receiver;
wherein the receiver generates a first received signal corresponding to the first frequency modulated output for a first duration, the first received signal being indicative of frequency modulations in the frequency modulated communications;
wherein the receiver generates a second received signal corresponding to the second frequency modulated output for a second duration, the second received signal being indicative of the frequency modulations in the frequency modulated communications, the first duration being different from the second duration;
demodulation circuitry configured to generate a first unmodulated signal based on the first received signal and a second unmodulated signal based on the second received signal, wherein the first unmodulated signal corresponds to the first duration and the second unmodulated signal corresponds to the second duration;
wherein a first phase of the first unmodulated signal is compared to a second phase of the second unmodulated signal, and wherein the phase difference is based on a comparison between the first phase and the second phase with respect to unmodulated signals obtained at different times and generated from the frequency modulated communications; and
wherein the demodulation circuitry is configured to decode the first received signal to generate a first modulation signal and to decode the second received signal to generate a second modulation signal, wherein the first unmodulated signal is an intermediate frequency signal based on the first modulation signal, and wherein the second unmodulated signal is an intermediate frequency signal based on the second modulation signal.

8. A method of determining an angle of arrival for frequency modulated communications, said method comprising:
generating a first frequency modulated output based on wireless receipt of the frequency modulated communications in a first antenna;
generating a second frequency modulated output based on wireless receipt of the frequency modulated communications in a second antenna, wherein the second antenna is separated by a distance from the first antenna;
producing first and second unmodulated forms of the first and second frequency modulated outputs;
determining a phase difference based on the first and second unmodulated forms such that the phase difference is determined irrespective of frequency modulations in the first and second frequency modulated outputs;
providing an oscillation signal at an oscillation frequency;
mixing the first frequency modulated output and the oscillation signal to generate a first intermediate frequency signal;
mixing the second frequency modulated output and the oscillation signal to generate a second intermediate frequency signal; and
determining the phase difference based on the first and second intermediate frequency signals, w

Assignees

• Denso Int America Inc
• Denso Corp

Inventors

• Stitt R Michael
• Guthrie Warren

Classifications

• H04L47/115

  using a dedicated packet · CPC title

• G01S3/50

  the waves arriving at the antennas being pulse modulated and the time difference of their arrival being measured · CPC title

• G01S3/043

  Receivers · CPC title

• H03D7/168

  using a feedback loop containing mixers or demodulators · CPC title

• G01S5/04

  Position of source determined by a plurality of spaced direction-finders · CPC title