# US 11,994,612 B2 · Systems and methods for phase-modulated radar detection

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- Number: US 11,994,612 B2
- Document ID: US11994612B2
- Status: Granted
- Kind: B2
- Application number: 17/324,963
- Filed: 2021-05-19
- Published: 2022-05-26
- Granted: 2024-05-28
- Earliest claimed: 2019-12-20
- Assignees: Oculii Corp.
- Applicants: Oculii Corp.
- Inventors: Lang Hong; Steven Hong
- Web page: https://patentgrep.com/patent/US11994612B2

## CPC

- G01S 7/354: {Extracting wanted echo-signals (Doppler systems G01S13/50)}
- G01S 13/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46)
- G01S 13/325: {using transmission of coded signals, e.g. P.S.K. signals}
- G01S 13/343: {using sawtooth modulation}
- G01S 7/356: {involving particularities of FFT processing}
- G01S 13/26: wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
- G01S 13/582: {adapted for simultaneous range and velocity measurements}
- G01S 13/584: {adapted for simultaneous range and velocity measurements}
- H04B 7/0413: MIMO systems
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- H04B: TRANSMISSION

## Abstract

A system for phase-modulated radar detection, preferably including one or more transmitter arrays, receiver arrays, and signal processors. A method for phase-modulated radar detection, preferably including transmitting a set of probe signals, receiving a set of reflected probe signals, and/or decoding the set of received probe signals, and optionally including evaluating effects of phase variance and/or modifying probe signal characteristics.

## Claims

### Claim 1

A method for radar detection, comprising:
at a set of transmit elements of a radar array, the set comprising a first transmit element and a second transmit element, transmitting a first code-division multiplexed set of radar probe signals, comprising:
based on a first encoding, transmitting a first encoded set of radar probe signals; and
substantially concurrent with transmitting the first encoded set, transmitting a second encoded set of radar probe signals;
at a receiver of the radar array, receiving a first set of reflected signals generated by reflection of the first code-division multiplexed set from at least one target in an environment surrounding the radar array;
based on the first encoding, demultiplexing the first set of reflected signals to generate a first decoded set of signals and a second decoded set of signals;
at the set of transmit elements, transmitting a second code-division multiplexed set of radar probe signals phase shifted from the first code-division multiplexed set based on a first set of phase variances, wherein transmitting the second code-division multiplexed set comprises:
based on the first encoding and the first set of phase variances, transmitting a third encoded set of radar probe signals; and
substantially concurrent with transmitting the third encoded set, transmitting a fourth encoded set of radar probe signals;
at a receiver of the radar array, receiving a second set of reflected signals generated by reflection of the second code-division multiplexed set from the at least one target;
based on the first encoding, demultiplexing the second set of reflected signals to generate a third decoded set of signals associated with the first transmit element and a fourth decoded set of signals; and
based on the first, second, third, and fourth decoded sets, determining target location information associated with the at least one target.

### Claim 2 (depends on 1)

The method of claim 1, wherein the target location information is associated with an interpolated virtual receive element location.

### Claim 3 (depends on 2)

The method of claim 2, further comprising, based on the first and second decoded sets of signals, determining target location information associated with a first receive element location and a second receive element location, wherein:
the first and second receive element locations define a first reference axis, wherein the first and second receive element locations are arranged along the first reference axis; and
the interpolated virtual receive element location is arranged along the first reference axis between the first receive element location and the second receive element location.

### Claim 4 (depends on 3)

The method of claim 3, wherein:
the first receive element location is located at a physical receive element of the receiver; and
the second receive element location is located at a virtual receive element defined by a radar system.

### Claim 5 (depends on 4)

The method of claim 4, wherein:
the radar array defines a first displacement vector from the first transmit element to the second transmit element; and
the virtual receive element is displaced from the physical receive element by the first displacement vector.

### Claim 6 (depends on 5)

The method of claim 5, wherein:
the first and second code-division multiplexed sets of radar probe signals define a radar wavelength; and
a length of the first displacement vector is substantially greater than half the radar wavelength.

### Claim 7 (depends on 6)

The method of claim 6, wherein a distance between the physical receive element and the interpolated virtual receive element location is substantially equal to half the radar wavelength.

### Claim 8 (depends on 5)

The method of claim 5, wherein:
the first encoded set is transmitted at the first transmit element; and
the second encoded set is transmitted at the second transmit element.

### Claim 9 (depends on 8)

The method of claim 8, wherein:
the third encoded set is transmitted at the first transmit element; and
the fourth encoded set is transmitted at the second transmit element.

### Claim 10 (depends on 5)

The method of claim 5, wherein:
the third encoded set is transmitted at the first transmit element; and
the fourth encoded set is transmitted at the second transmit element.

### Claim 11 (depends on 3)

The method of claim 3, wherein:
the first receive element location is located at a first physical receive element of the receiver; and
the second receive element location is located at a second physical receive element of the receiver.

### Claim 12 (depends on 3)

The method of claim 3, wherein:
demultiplexing the first set of reflected signals further generates a fifth decoded set of signals;
demultiplexing the second set of reflected signals further generates a sixth decoded set of signals;
the method further comprises, based on the fifth decoded set, determining target location information associated with a third receive element location;
determining target location information is performed based further on the fifth and sixth decoded sets;
the target location information is further associated with a second interpolated virtual receive element location;
the first and third receive element locations define a second reference axis;
the first and third receive element locations are arranged along the second reference axis;
the first and second reference axes define a non-zero angle between them;
the first and second reference axes define a reference plane; and
the second interpolated virtual receive element location is arranged on the reference plane.

### Claim 13 (depends on 2)

The method of claim 2, wherein demultiplexing the first set of reflected signals further generates the third decoded set of signals; the method further comprising, based on the first, second, and third decoded sets, determining target location information associated with a first receive element location, a second receive element location, and a third receive element location, wherein:
the first, second, and third receive element locations define a first reference triangle, wherein the first, second, and third receive element locations are each arranged at a different vertex of the first reference triangle; and
the interpolated virtual receive element location is arranged within the first reference triangle.

### Claim 14 (depends on 13)

The method of claim 13, wherein:
the first receive element location is located at a physical receive element of the receiver; and
the second receive element location is located at a first virtual receive element defined by a radar system.

### Claim 15 (depends on 14)

The method of claim 14, wherein the third receive element location is located at a second virtual receive element defined by the radar system.

### Claim 16 (depends on 1)

The method of claim 1, wherein the first set of phase variances are associated with a first beam steering angle for the set of transmit elements.

### Claim 17 (depends on 1)

The method of claim 1, wherein each phase variance of the first set has a respective magnitude less than or equal to 10°.

### Claim 18 (depends on 1)

The method of claim 1, wherein the second encoded set of radar probe signals is transmitted based on a second encoding substantially orthogonal to the first encoding.

### Claim 19 (depends on 18)

The method of claim 18, wherein the first and second encodings are binary phase modulation encodings.

### Claim 20 (depends on 1)

The method of claim 1, further comprising:
determining that a Doppler variance of the first and second sets of reflected signals is less than a threshold value;
in response to determining that the Doppler variance is less than the threshold value:
determining a second set of phase variances, different from the first set of phase variances; and
at the set of transmit elements, transmitting a third code-division multiplexed set of radar probe signals phase shifted from the first code-division multiplexed set based on the second set of phase variances;
at the receiver of the radar array, receiving a third set of reflected signals generated by reflection of the third code-division multiplexed set from the at least one target; and
based on the third set of reflected signals, determining refined target information associated with the at least one target.