Fast spatial search using phased array antennas

Patent metadata

Field	Value
Publication number	US-11152986-B2
Application number	US-201916451590-A
Country	US
Kind code	B2
Filing date	Jun 25, 2019
Priority date	Jun 25, 2019
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

Systems and methods for rapidly finding detectable signals within the field-of-view of a phased array antenna. The transmit beam pattern is modified over time to increase signal spatial search performance over typical time-delay steering by producing a coarse-to-fine angular beam pattern with a tree-based approach to signal detection. A tree-based beam search is employed to select a beam having a narrower beamwidth for transmission at an angle from boresight that lies in an angular space where a signal has been previously detected.

First claim

The invention claimed is:

1. A method for searching for signals using a phased array antenna, the method comprising:
designing a complementary beam tree having first through L-th levels, wherein an index l indicates an l-th level of a total number of levels L, and the l-th level has 2 l-1 M beams;
loading the L levels of the complementary beam tree into a beam steering controller that controls the beams created by the phased array antenna;
marking pre-selected beams in the complementary beam tree for the first through (L−1)-th levels;
for each search frame, performing steps (a) through (g) comprising:
(a) setting phases and amplitudes of antenna elements of the phased array antenna to transmit the pre-selected marked beams in succession;
(b) transmitting the pre-selected marked beams in succession;
(c) following each transmission of a beam, detecting whether a value of a parameter of a received signal indicates that a signal was received which corresponds to the transmitted beam or not;
(d) following each detection that a signal was received which corresponds to the transmitted beam, marking two narrower beams at a next level having respective bandwidths which are narrower than and overlap with respective portions of a bandwidth of the transmitted beam;
(e) setting phases and amplitudes of antenna elements of the phased array antenna to transmit the two marked narrower beams;
(f) transmitting the two marked narrower beams in succession;
(g) following each transmission of a marked narrower beam, iteratively repeating steps (c) through (f) before transmitting a next pre-selected marked beam in step (b);
marking a first subset of additional narrowest beams from the L-th level in order to fill in search gaps after steps (a) through (e) have been iteratively performed for a first search frame of the successive search frames;
setting phases and amplitudes of antenna elements of the phased array antenna to transmit the first subset of marked additional narrowest beams for the first search frame;
marking a second subset of additional narrowest beams from the L-th level in order to fill in search gaps after steps (a) through (e) have been iteratively performed for a second search frame of the successive search frames; and
setting phases and amplitudes of antenna elements of the phased array antenna to transmit the second subset of additional marked beams for the second search frame; and
wherein the first and second subsets of additional narrowest beams at the L-th level are mutually exclusive.

2. A phased array antenna system comprising:
a phased array antenna;
a transmitter;
a receiver;
a transmit module that connects the transmitter to the phased array antenna in a transmit mode and connects the receiver to the phased array antenna in a receive mode;
a beam steering controller configured to control the phased array antenna to transmit beams having beamwidths and angles from boresight which are determined by a tree-based beam search;
a beam search controller configured to send commands to the transmitter and beam steering controller, which commands cause beams selected by a tree-based beam search to be transmitted by the phased array antenna; and
a complementary beam set data storage medium storing data representing specifications of beams of a complementary beam tree organized in L levels, wherein an index l indicates an l-th level of a total number of levels L and the l-th level has 2 l-1 M beams;
wherein the complementary beam set data storage medium is accessible by both the beam search controller and the beam steering controller, the beam search controller is further configured to mark selected beams specified in the complementary beam set data storage medium, and the beam steering controller is further configured to control the beams created by a phased array antenna in dependence on beam information read from the complementary beam set data storage medium for each search frame of a succession of search frames, and
wherein the system is configured to perform the following beam tree search for signals:
(a) the beam search controller sets phases and amplitudes of antenna elements of the phased array antenna to transmit pre-selected marked beams in succession;
(b) the transmitter transmits the pre-selected marked beams in succession;
(c) following each transmission of a beam, the beam search controller detects whether a value of a parameter of a received signal indicates that a signal was received which corresponds to the transmitted beam or not;
(d) following each detection that a signal was received which corresponds to the transmitted beam, the beam search controller marks two narrower beams at a next level having respective bandwidths which are narrower than and overlap with respective portions of a bandwidth of the transmitted beam;
(e) the beam steering controller sets phases and amplitudes of antenna elements of the phased array antenna to transmit the two marked narrower beams;
(f) the transmitter transmits the two marked narrower beams in succession;
following each transmission of a marked narrower beam, the system iteratively repeats steps (c) through (f) before transmitting a next pre-selected marked beam in step (b);
the beam search controller marks a first subset of additional narrowest beams from the L-th level in order to fill in search gaps after steps (a) through (e) have been iteratively performed for a first search frame of the successive search frames;
the beam steering controller sets phases and amplitudes of antenna elements of the phased array antenna to transmit the first subset of marked additional narrowest beams for the first search frame;
the beam search controller marks a second subset of additional narrowest beams from the L-th level in order to fill in search gaps after steps (a) through (e) have been iteratively performed for a second search frame of the successive search frames; and
the beam steering controller sets phases and amplitudes of antenna elements of the phased array antenna to transmit the second subset of additional marked beams for the second search frame; and
wherein the first and second subsets of additional narrowest beams at the L-th level are mutually exclusive.

3. The phased array antenna system as recited in claim 2 , wherein the beam search controller comprises a module configured for detecting a particular parameter of signals output by the receiver.

4. The phased array antenna system as recited in claim 2 , wherein the first level includes beams having a first beamwidth, the second level includes beams having a second beamwidth which is less than the first beamwidth, the third level includes beams having a third beamwidth which is less than the second beamwidth, and the L-th level includes beams having an L-th beamwidth which is less than the third beamwidth and less than a beamwidth of any level between the third level and the L-th level.

5. A phased array antenna system comprising:
a phased array antenna;
a transmitter;
a receiver;
a transmit module that connects the transmitter to the phased array antenna in a transmit mode and connects the receiver to the phased array antenna in a receive mode;
a beam steering controller configured to control the phased array antenna to transmit beams having beamwidths and angles from boresight which are determined by a tree-based beam search;
a beam search controller configured to send commands to the transmitter and beam steering controller, which commands cause beams selected by a tree-based beam search to be transmitted by the phased array antenna; and
a complementary beam set data storage medium storing data representing specifications of beams of a complementary beam set organized in L levels, wherein an index l indicates an l-th level of a total number of levels L and an i

Assignees

• Boeing Co

Inventors

• Ray Gary A

Classifications

• G01S7/2925

  by using shape of radiation pattern · CPC title

• H01Q3/30

  varying the {relative} phase {between the radiating elements of an array (H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence)} · CPC title

• H01Q3/267

  Phased-array testing or checking devices · CPC title

• G01S13/422

  sequential lobing, e.g. conical scan · CPC title

• G01S2013/0263

  Passive array antenna · CPC title