Methods and Apparatus for Velocity Detection in MIMO Radar Including Velocity Ambiguity Resolution

Patent metadata

Field	Value
Publication number	US-2020209352-A1
Application number	US-202016814531-A
Country	US
Kind code	A1
Filing date	Mar 10, 2020
Priority date	Jul 9, 2016
Publication date	Jul 2, 2020
Grant date	—

Abstract

In accordance with described examples, a method determines if a velocity of an object detected by a radar is greater than a maximum velocity by receiving on a plurality of receivers at least one frame of chirps transmitted by at least two transmitters and reflected off of the object. A velocity induced phase shift (φ d ) in a virtual array vector S of signals received by each receiver corresponding to a sequence of chirps (frame) transmitted by each transmitter is estimated. Phases of each element of virtual array vector S are corrected using φ d to generate a corrected virtual array vector S c . A first Fourier transform is performed on the corrected virtual array vector S c to generate a corrected virtual array spectrum to detect a signature that indicates that the object has an absolute velocity greater than a maximum velocity.

First claim

What is claimed is:

1 . A circuit comprising:
a port adapted to be coupled to a receiver and configured to receive a plurality of chirps; a processor coupled to the port and configured to:
estimate a phase shift (φ d ) in a virtual array vector S of signals based on the plurality of chirps received by the port;
correct the phases of each element of virtual array vector S using φ d to generate a corrected virtual array vector S c ;
perform a first Fourier transform on the corrected virtual array vector S c to generate a corrected virtual array spectrum; and
analyze the corrected virtual array spectrum to detect a signature that indicates that an object corresponding to the detected signature has an absolute velocity greater than a maximum velocity.

2 . The circuit of claim 1 in which the processor is further configured to correct the corrected virtual array vector S c using a phase error vector corresponding to the detected signature and perform a second Fourier transform on a resulting matrix to determine if the signature is removed from the resulting matrix.

3 . The circuit of claim 1 in which the processor is configured to calculate a velocity of the object using formulas

v
est

=

ϕ
d


λ

4



π




T
c

,

where T c is a chirp period and λ is a wavelength of the chirps and v true =v est +2v max (if v est <0) or v true =v est −2v max (if v est >0), where v true is the correct velocity and v max is determined by the formula

v
max

=

λ

4




T
c

.

4 . The circuit of claim 1 in which the processor further determines if the signature is caused by multiple objects by analyzing S c .

5 . A method comprising:
receiving, by a receiver, a plurality of chirps; estimating a phase shift (φ d ) in a virtual array vector S of signals based on the received plurality of chirps; correcting phases of each element of virtual array vector S using φ d to generate a corrected virtual array vector S c ; performing a first Fourier transform on the corrected virtual array vector S c to generate a corrected virtual array spectrum; and analyzing the corrected virtual array spectrum to detect a signature that indicates that an object corresponding to the detected signature has an absolute velocity greater than a maximum velocity.

6 . The method of claim 5 further comprising correcting the corrected virtual array vector S c using a phase error vector corresponding to the detected signature and performing a second Fourier transform on a resulting matrix to determine if the signature is removed from the resulting matrix.

7 . The method of claim 5 further comprising determining a velocity of the object by using formulas

v
est

=

ϕ
d


λ

4



π




T
c

,

where T c is a chirp period and λ is a wavelength of the chirps and v true =v est +2v max (if v est ∠0) or v true =v est −2v max (if v est ∠0), where v true is the correct velocity and v max is determined by the formula

v
max

=

λ

4




T
c

.

8 . The method of claim 5 further comprising determining if the signature is caused by multiple objects by analyzing S c .

9 . A radar system comprising:
a receiver configured to receive a plurality of chirps; a processor coupled to the receiver and configured to:
estimate a phase shift (φ d ) in a virtual array vector S of signals based on the received plurality of chirps;
correct the phases of each element of virtual array vector S using φ d to generate a corrected virtual array vector S c ;
perform a first Fourier transform on the corrected virtual array vector S c to generate a corrected virtual array spectrum; and
analyze the corrected virtual array spectrum to detect a signature that indicates that an object corresponding to the detected signature has an absolute velocity greater than a maximum velocity.

10 . The radar system of claim 9 in which the processor is further configured to correct the corrected virtual array vector S c using a phase error vector corresponding the signature and perform a second Fourier transform on a resulting matrix to determine if the signature is removed from the resulting matrix.

11 . The radar system of claim 9 in which the processor further determines a velocity of the object.

12 . The radar system of claim 11 in which the processor further determines a velocity of the object using formulas

v
est

=

ϕ
d


λ

4



π


Assignees

• Texas Instruments Inc

Inventors

• Rao Sandeep
• Subburaj Karthik
• Wang Dan
• Ahmad Adeel

Classifications

• G01S7/356

  involving particularities of FFT processing · CPC title

• G01S13/42

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) · CPC title

• G01S13/343

  using sawtooth modulation · CPC title

• G01S7/354 Primary

  Extracting wanted echo-signals (Doppler systems G01S13/50) · CPC title

• G01S13/92

  for velocity measurement · CPC title