Proximity radar method and system for a rotary-wing aircraft

Patent metadata

Field	Value
Publication number	US-11353580-B2
Application number	US-201916708194-A
Country	US
Kind code	B2
Filing date	Dec 9, 2019
Priority date	Dec 20, 2018
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

A proximity radar method for a rotary-wing aircraft includes a sequence of phases T(k) of steps. In a first phase T(1), the electronic computer of the radar system computes unambiguous synthetic patterns on the basis of a first activated interferometric pattern M(1) of N unitary radiating groups. In the following phases T(k) of steps, executed successively in increasing order of k, the electronic computer computes synthetic patterns on the basis of interferometric patterns M(k) of rank k, wherein the N unitary radiating groups of a series deviate simultaneously in terms of azimuth and in terms of elevation as k increases, and establishes maps of rank k of the surroundings in terms of azimuth distance/direction and/or elevation distance/direction cells wherein the detected obstacle ambiguities, associated with the network lobes, are removed by virtue of the map(s) provided in the preceding phase or phases.

First claim

The invention claimed is:

1. A proximity radar method for a rotary-wing aircraft, implemented by a proximity radar system comprising at least one radar sensor having:
an antenna panel, formed of a whole number N greater than or equal to 2 of reception sectors and at least one emission sector; and
N reception channels configured so as to independently demodulate and then respectively digitize the N reception sectors; and
an emission channel, configured so as to modulate a radar emission waveform on a radar carrier to be emitted by the at least one emission sector;
an electronic computer, configured so as to perform proximity radar processing operations and fuse direction/distance map data; and
a display for displaying the proximity situation of the aircraft;
the N reception sectors being distributed around a predetermined common central point O; and
each of the N reception sectors having one and the same number NK, greater than or equal to 2, of unitary radiating groups whose position in terms of azimuth and/or in terms of elevation varies between the central point O and the periphery of their sector, and pointing in one and the same pointing direction with an identical radiation pattern,
the proximity radar method comprising a sequence of phases T(k) of steps, executed successively as a function of k, k varying from 1 to NK, wherein:
each phase T(k) of steps consists in the electronic computer activating, with an interferometric pattern M(k) associated with the rank k, at a rate of one radiating group per reception sector, N active radiating groups associated with said interferometric pattern M(k), whose position in terms of azimuth and/or in terms of elevation varies as a function of the temporal rank k between the central point O and the periphery of their sector without passing through one and the same position again, so as to produce, in correlation, synthetic patterns during computational reception beamforming with a lobe width and the appearance of a number of network lobes that vary as a function of the temporal rank k, and so as to establish a map of rank k of the surroundings in terms of azimuth distance/direction and/or elevation distance/direction cells wherein the detected obstacle ambiguities, associated with the network lobes, are removed by virtue of the map(s) provided in the phase or phases preceding and/or following the phase T(k).

2. The proximity radar method as claimed in claim 1 , wherein
the N reception sectors are distributed angularly around a predetermined common central point O; and
each of the N reception sectors has one and the same number NK, greater than or equal to 2, of unitary radiating groups that deviate in terms of azimuth and/or in terms of elevation toward the periphery of their sector, and pointing in one and the same pointing direction with an identical radiation pattern; and
the sequence of phases T(k) of steps of the proximity radar method, k varying from 1 to NK, is wherein:
in a first phase T( 1 ), the electronic computer activates, with a first interferometric pattern M( 1 ), at a rate of one active radiating group per reception sector, N active radiating groups closest to the common central point O of the reception sectors, so as to obtain unambiguous synthetic patterns during computational reception beamforming; and then
in the following phases T(k) of steps, executed successively in increasing order of k, for k varying from 2 to NK,
the phase T(k) of steps consists in the electronic computer activating, with an interferometric pattern M(k) associated with the rank k, at a rate of one radiating group per reception sector, N active radiating groups associated with said pattern M(k), deviating more in terms of azimuth and/or in terms of elevation the greater the temporal rank k, so as to produce, in correlation, synthetic patterns during computational reception beamforming with a lobe width half that of the lobes of the preceding pattern M(k−1), and the appearance of a number of network lobes equal to 2 times 2k−1, and so as to establish a map of rank k of the surroundings in terms of azimuth distance/direction and/or elevation distance/direction cells wherein the detected obstacle ambiguities, associated with the network lobes, are removed by virtue of the map(s) provided in the phase or phases preceding the phase T(k).

3. The proximity radar method as claimed in claim 2 , wherein, for each phase T(k) of steps, k varying from 1 to NK, the electronic computer executes a first step, a second step and a third step;
the first step, executed in the phase T(k), consisting in the electronic computer activating N unitary radiating groups associated with an interferometric pattern M(k), wherein, for k equal to 1, the first pattern M( 1 ) is formed of the N active radiating groups, at a rate of one active radiating group per reception sector, that are closest to the common central point O of the reception sectors, and for k between 2 and NK, the pattern of order k, M(k), is formed of the closest adjacent N active radiating groups, at a rate of one active radiating group per reception sector, that deviate simultaneously in terms of azimuth and in terms of elevation from the active radiating groups of the preceding pattern M(k−1); and the signals received by the N reception sectors associated with the pattern M(k) are demodulated and digitized independently on the corresponding digitized channels and supplied to the electronic computer; and
the second step, executed in the phase T(k), k being between 1 and NK, consisting in two synthetic beams being formed through computation by the electronic computer on the basis of the signals from the N demodulated and digitized sectors by combining said N signals from the reception sectors by suitable phase-shifting operations, 2*(2k−1) network lobes being created in said synthetic beams starting from a rank k equal to 2; and
the third step, executed in the phase T(k), consisting in the computer establishing, on the basis of the synthetic beams computed for the pattern M(k) of rank k, a map of rank k of the surroundings in terms of azimuth distance/direction cells expressed as a direction cosine and/or elevation distance/direction cells expressed as a direction and direction/distance cosine and fusing the map of rank k with the map of preceding rank k−1 when k is greater than or equal to 2 in order to remove possible detected obstacle ambiguities.

4. The proximity radar method as claimed in claim 3 , furthermore comprising a display step executed after the third step of each phase T(k) starting from a predetermined rank k greater than or equal to 2, wherein
the display is configured so as to display the proximity situation of the aircraft, highlight approaching hazards and warnings.

5. The proximity radar method as claimed in claim 1 , wherein
the at least one emission sector is contained within the reception sectors and the proximity radar operates in a monostatic mode; or
the at least one emission sector is separate and remote from the reception sectors and the proximity radar operates in a bistatic mode.

6. The proximity radar method as claimed in claim 5 , wherein
when the radar operates in a bistatic mode,
at least one unitary emission radiating group, configured so as to point in the same pointing direction as that of the unitary radiating groups of the reception sectors and having the same radiation pattern, is activated statically; and/or
at least two unitary emission radiating groups configured so as to point in the same pointing direction as that of the unitary radiating groups of the reception sectors and having the same radiation pattern are activated dynamically, by making the activation of the radiating groups circulate so as to follow at least one circulation vector.

7. A

Assignees

• Thales Sa

Inventors

• Veyrac Yoan
• Inconstante Jérémy
• Garrec Patrick
• Montigny Richard
• Cornic Pascal

Classifications

• G01S13/933

  of aircraft or spacecraft · CPC title

• G01S13/48

  using multiple beams at emission or reception · CPC title

• B64C27/04

  Helicopters · CPC title

• B64C1/36 Primary

  adapted to receive antennas or radomes · CPC title

• G08G5/21

  located onboard the aircraft · CPC title