Near range radar

Patent metadata

Field	Value
Publication number	US-11709244-B2
Application number	US-202017036255-A
Country	US
Kind code	B2
Filing date	Sep 29, 2020
Priority date	Oct 21, 2019
Publication date	Jul 25, 2023
Grant date	Jul 25, 2023

Abstract

Apparatus and associated methods relate to enabling a radar system to use different sensing mechanisms to estimate a distance from a target based on different detection zones (e.g., far-field and near-field). In an illustrative example, a curve fitting method may be applied for near-field sensing, and a Fourier transform may be used for far-field sensing. A predetermined set of rules may be applied to select when to use the near-field sensing mechanism and when to use the far-field mechanism. The frequency of a target signal within a beat signal that has less than two sinusoidal cycles may be estimated with improved accuracy. Accordingly, the distance of a target that is within a predetermined distance range (e.g., two meters range for 24 GHz ISM band limitation) may be reliably estimated.

First claim

What is claimed is:

1. A radar system comprising:
(a) a transmitting circuit configured to transmit a radar signal to a target;
(b) a receiving circuit configured to receive a reflected portion of the transmitted radar signal from the target;
(c) a mixer circuit configured to produce a beat signal between the reflected radar signal and the transmitted radar signal;
(d) a signal processing engine; and
(e) a data store coupled to the signal processing engine, wherein the data store comprises a program of instructions that, when executed by the signal processing engine, cause the signal processing engine to perform operations to compute a distance measurement to the target, the operations comprising:
(i) performing a time-domain estimation algorithm to estimate a first frequency of a target signal within the beat signal using a curve fitting method,
(ii) performing a frequency-domain estimation algorithm to estimate a second frequency of the target signal using a Fourier transform method,
(iii) determining whether the first frequency is less than a first predetermined frequency and determining whether the second frequency is larger than a second predetermined frequency,
(iv) if the first frequency is less than the first predetermined frequency, then, selecting the first frequency to compute the distance measurement to the target,
(v) if the second frequency is larger than the second predetermined frequency, then, selecting the second frequency to compute the distance measurement to the target, and
(vi) if both the first frequency and the second frequency are ranged between the first predetermined frequency and the second predetermined frequency, then, using a combination of the first frequency and the second frequency to compute the distance measurement to the target.

2. The radar system of claim 1 , wherein the first predetermined frequency and the second predetermined frequency are each between one and three cycles within a radar's sweep period.

3. The radar system of claim 1 , the operations further comprising:
comparing the computed distance measurement with a set of thresholds to determine validity of the computed distance.

4. The radar system of claim 1 , the operations further comprising:
comparing a measured phase with a set of thresholds to further determine validity of the computed distance, the phase being obtained from the frequency used to compute the distance measurement.

5. The radar system of claim 1 , the operations further comprising:
comparing a measured amplitude with a set of thresholds to further determine validity of the computed distance, the amplitude being obtained from the frequency used to compute the distance measurement.

6. The radar system of claim 1 , wherein the beat signal comprises low frequency noise signals.

7. The radar system of claim 6 , wherein the low frequency noise signals comprise voltage-controlled oscillator (VCO) crosstalk noise.

8. The radar system of claim 6 , wherein the low frequency noise signals comprise one or more radome reflection signals.

9. The radar system of claim 1 , the operations further comprising:
utilizing a plurality of target estimations from the time-domain frequency estimation and the frequency-domain frequency estimation before determining a final target frequency estimation.

10. A radar system comprising:
(a) a transmitting circuit configured to transmit a radar signal to a target;
(b) a receiving circuit configured to receive a reflected portion of the transmitted radar signal from the target;
(c) a mixer circuit configured to produce a beat signal between the reflected radar signal and the transmitted radar signal, wherein the beat signal comprises a plurality of frequencies;
(d) a signal processing engine; and,
(e) a data store coupled to the signal processing engine, wherein the data store contains a program of instructions that, when executed by the signal processing engine, cause the signal processing engine to perform operations to perform a target distance measurement, the operations comprising:
(i) performing a time-domain estimation algorithm on the beat signal in the time domain to generate an estimate of a single frequency of a target signal within the beat signal using a curve fitting method, the single frequency having less than a predetermined number of sinusoidal cycles, and
(ii) computing the distance to the target based on the estimated single frequency of the target signal.

11. The radar system of claim 10 , wherein the estimated frequency is less than three cycles within a radar's sweep period.

12. The radar system of claim 10 , wherein the estimated frequency is less than one cycle within a radar's sweep period.

13. The radar system of claim 10 , wherein the estimated frequency is generated by machine learning.

14. The radar system of claim 10 , wherein the curve-fitting method comprises a sine fit transform.

15. The radar system of claim 10 , the operations further comprising:
(iii) comparing the computed distance obtained from the estimated frequency with a set of thresholds to determine validity of the computed distance.

16. The radar system of claim 10 , the operations further comprising:
(iii) comparing a measured phase obtained from the estimated frequency with a set of thresholds to determine validity of the computed distance.

17. The radar system of claim 10 , the operations further comprising:
(iii) comparing a measured amplitude obtained from the estimated frequency with a set of thresholds to determine validity of the computed distance.

18. The radar system of claim 10 , wherein the beat signal comprises low frequency noise signals.

19. The radar system of claim 18 , wherein a plurality of phases is used to separate the target signal from the low frequency noise signals within the beat signal.

20. The radar system of claim 18 , wherein the low frequency noise signals comprise voltage-controlled oscillator (VCO) crosstalk noise.

21. The radar system of claim 18 , wherein the low frequency noise signals comprise at least one radome reflection signals.

22. The radar system of claim 10 , the operations further comprising:
(iii) utilizing a plurality of target estimations before determining a final target frequency estimation.

23. The radar system of claim 10 , wherein a plurality of phases of the target signal are used to estimate the frequency and validity of the target signal.

24. A radar system comprising:
(a) a transmitting circuit configured to transmit a radar signal to a target;
(b) a receiving circuit configured to receive a reflected portion of the transmitted radar signal from the target and detect a beat signal between the reflected radar signal and the transmitted radar signal;
(c) a mixer circuit configured to produce a beat signal between the reflected radar signal and the transmitted radar signal;
(d) a curve fit engine configured to receive the beat signal and perform a curve fitting method on the beat signal to measure a frequency of a target signal within the beat signal;
(e) a Fourier transform engine configured to receive the beat signal and perform a Fourier transform on the beat signal to measure the frequency of the target signal;
(f) a controller, operably coupled to the curve fit engine and the Fourier transform engine, configured to selectively use a first frequency estimated by the curve fit engine and a second frequency estimated the Fourier transform engine in resp

Assignees

• Banner Eng

Inventors

• Wise Ashley
• Kang Chunmei
• Oberpriller Wade

Classifications

• G01S13/342 Primary

  using sinusoidal modulation · CPC title

• G01S13/347

  using more than one modulation frequency · CPC title

• G01S7/352

  Receivers · CPC title

• G01S13/34 Primary

  using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal · CPC title

• G01S13/931

  of land vehicles · CPC title