Digital active array radar

Patent metadata

Field	Value
Publication number	US-9897695-B2
Application number	US-201414488129-A
Country	US
Kind code	B2
Filing date	Sep 16, 2014
Priority date	Oct 3, 2013
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

A frequency-modulation, continuous-wave (FMCW) radar system may include a transmit array including a number of transmit antenna elements in a first dimension that is greater than a number of transmit antenna elements in a second dimension. The transmit array may output an FMCW transmit beam that illuminates an area with a greater extent in a first illumination dimension than in a second illumination dimension. The radar system may include a transmit electronics module that electronically scans the transmit beam in the second illumination dimension, and a receive array comprising receive antenna elements. The radar system may include a receive electronics module that generates, using a plurality of receive signals, a plurality of receive beams within the area illuminated by the transmit beam and electronically scans each receive beam in the second illumination dimension such that scanning of each receive beam is coordinated with scanning of the transmit beam.

First claim

What is claimed is:

1. A frequency modulation continuous wave (FMCW) radar system comprising:
a transmit array comprising a plurality of transmit antenna elements arranged such that a number of transmit antenna elements in a first transmit array dimension is greater than a number of transmit antenna elements in a second transmit array dimension substantially perpendicular to the first transmit array dimension, wherein the transmit array is configured to output an FMCW transmit beam that illuminates an area with a greater extent in a first illumination dimension than in a second illumination dimension substantially perpendicular to the first illumination dimension;
a transmit electronics module operable to electronically scan the FMCW transmit beam in the second illumination dimension;
a receive array comprising a plurality of receive antenna elements; and
a receive electronics module operable to generate, using a plurality of receive signals received from the receive array, a plurality of receive beams within the area illuminated by the FMCW transmit beam and electronically scan each receive beam of the plurality of receive beams in the second illumination dimension such that the scanning of each receive beam is coordinated with the scanning of the FMCW transmit beam in the second illumination dimension.

2. The FMCW radar system of claim 1 , wherein the first transmit array dimension comprises a substantially horizontal row, wherein the second transmit array dimension comprises a substantially vertical column, wherein the first illumination dimension comprises an elevation, and wherein the second illumination dimension comprises an azimuth.

3. The FMCW radar system of claim 1 , wherein the transmit array comprises a plurality of transmit arrays and the receive array comprises a plurality of receive arrays, and wherein each transmit array of the plurality of transmit arrays is configured to output a respective FMCW transmit beam that illuminates an area with a greater extent in the first illumination dimension than in the second illumination dimension.

4. The FMCW wave radar system of claim 1 , wherein the transmit electronics module comprises at least one direct digital synthesizer operable to generate a phase shift for each respective transmit signal output to each of the plurality of transmit antenna elements to electronically scan the FMCW transmit beam in the second illumination dimension.

5. The FMCW radar system of claim 1 , wherein the transmit electronics module comprises:
at least one direct digital synthesizer operable to generate an intermediate frequency signal comprising an I signal and a Q signal, apply a phase offset to the I signal to form a phase-shifted I signal and apply the phase offset to the Q signal to form a phase-shifted Q signal;
at least one image reject mixer operable to receive the phase-shifted I signal and the phase-shifted Q signal from the at least one direct digital synthesizer and a radio frequency signal from a corporate feed and generate an FMCW transmit signal that is offset from the radio frequency signal by the intermediate frequency;
at least one amplifier operable to receive and amplify the FMCW signal and output the amplified FMCW transmit signal to a transmit antenna element of the plurality of transmit antenna elements.

6. The FMCW radar system of claim 1 , wherein the receive array is electrically divided into quadrants, each quadrant comprising a plurality of receive antenna elements arranged in a plurality of rows, each row of the plurality of rows comprising a plurality of receive antenna elements.

7. The FMCW radar system of claim 6 , wherein the receive electronics module comprises:
at least one analog receive electronics module operable to:
heterodyne each respective receive signal of the plurality of receive signals to an intermediate frequency by mixing the respective receive signal and a radio frequency signal from a corporate feed;
downconvert the respective intermediate frequency receive signals to baseband frequency using a reference clock signal having a frequency that is an integer multiple of the intermediate frequency to form respective baseband frequency receive signals
apply a phase shift to each baseband frequency receive signal to scan the plurality of receive beams in the second illumination dimension; and
sum I signals and Q signals for each row of each quadrant to form a plurality of summed I signals and a plurality of summed Q signals, wherein the number of summed I signals for each quadrant corresponds to the number of rows in the respective quadrant and the number of summed Q signals for each quadrant corresponds to the number of rows in the respective quadrant; and

at least one digital receive electronics module operable to form the plurality of receive beams by at least applying a plurality of complex beam weights to the plurality of summed I signals and the plurality of summed Q signals.

8. The FMCW radar system of claim 7 , wherein:
the plurality of complex beam weights applied to the plurality of summed I signals generate weighted I data streams and the plurality of complex beam weights applied to the plurality of summed Q signals generate weighted Q data streams, and
the at least one digital receive electronics module is further operable to generate the plurality of receive beams, each receive beam of the plurality beams located at a predetermined first illumination dimension position.

9. The FMCW radar system of claim 8 , wherein the at least one digital receive electronics module is further operable to generate monopulse tracking beams for each receive beam.

10. A method comprising:
outputting, by a transmit array comprising a plurality of transmit antenna elements, a frequency modulated continuous wave (FMCW) transmit beam, wherein the plurality of transmit antenna elements are arranged such that a number of transmit antenna elements in a first transmit array dimension is greater than a number of transmit antenna elements in a second transmit array dimension substantially perpendicular to the first transmit array dimension, and wherein the FMCW transmit beam illuminates an area with a greater extent in a first illumination dimension than in a second illumination dimension substantially perpendicular to the first illumination dimension;
electronically scanning, by a transmit electronics module, the FMCW transmit beam in the second illumination dimension;
receiving, by a receive electronics module, a plurality of receive signals from a receive array comprising a plurality of receive antenna elements; and
electronically generating and scanning in the second illumination dimension, by the receive electronics module, a plurality of receive beams such that the scanning of each receive beam is coordinated with the scanning of the FMCW transmit beam so that the plurality of receive beams are within the area illuminated by the FMCW transmit beam throughout the scanning of the FMCW transmit beam and the plurality of receive beams in the second illumination dimension.

11. The method of claim 10 , wherein the first transmit array dimension comprises a substantially horizontal row, wherein the second transmit array dimension comprises a substantially vertical column, wherein the first illumination dimension comprises an elevation, and wherein the second illumination dimension comprises an azimuth.

12. The method of claim 10 , wherein the transmit electronics module comprises at least one direct digital synthesizer, and wherein electronically scanning the FMCW transmit beam in the second illumination dimension comprises:
generating, by at least one direct digital synthesizer, a phase shift for each

Assignees

• Honeywell Int Inc

Inventors

• Vacanti David C

Classifications

• H01Q1/28

  Adaptation for use in or on aircraft, missiles, satellites, or balloons · CPC title

• H01Q21/065

  Patch antenna array · CPC title

• H01Q1/42

  Housings not intimately mechanically associated with radiating elements, e.g. radome · CPC title

• G01S7/352

  Receivers · CPC title

• G01S7/35

  Details of non-pulse systems · CPC title