Method and system for determining an angle of arrival of a radioelectric signal

Patent metadata

Field	Value
Publication number	US-11249166-B2
Application number	US-201916450645-A
Country	US
Kind code	B2
Filing date	Jun 24, 2019
Priority date	Jun 26, 2018
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

The invention relates to a method for determining an angle of arrival of a received radioelectric signal implemented by a receiving antenna system including either one rotating antenna having at least two receiving channels, or two rotating antennas with a same speed each having a receiving channel, and having different antenna diagrams. The method includes calculating and storing a series of ambiguous angle error measurement values obtained from receiving amplitude values of a radioelectric signal coming from an emitting source on said first and second receiving channels, calculating a convolution function on said angular range tween said series of ambiguous angle error measurement values and a series of theoretical angle error measurement values of said receiving channels previously calculated and stored, and determining an angle of arrival of said received radioelectric signal as a function of an estimate of a maximum of said calculated convolution function.

First claim

The invention claimed is:

1. A method for determining an angle of arrival of a received radioelectric signal implemented by a receiving antenna system including either one rotating antenna having at least two receiving channels, or two rotating antennas with a same rotation speed each having a receiving channel,
a first receiving channel having a first antenna diagram and a second receiving channel having a second antenna diagram, said first and second antenna diagrams being different,
comprising, in an operational phase:
calculating and storing a series of ambiguous angle error measurement values obtained from receiving amplitude values of a radioelectric signal coming from an emitting source on said first and second receiving channels, said radioelectric signal being received on said first and second receiving channels by the one or two rotating antennas over a predetermined angular range, each angle error measurement value being representative of a ratio between receiving amplitude values on said first and second receiving channels, and corresponding to an angular deviation relative to a reference angular value,

wherein the calculation of a series of ambiguous angle error measurement values comprises:
obtaining receiving amplitude values on said first and second receiving channels, each amplitude value being associated with an angular value;
for the first receiving channel, for each angular value, calculating a so-called synthetic receiving amplitude value, equal to a maximum between the receiving amplitude value on the first receiving channel and the receiving amplitude value on the second receiving channel;
for each angular value, calculating an ambiguous angle error measurement value by obtaining the ratio between the receiving amplitude value on the second receiving channel and the corresponding synthetic receiving amplitude value;

the method further comprising:
calculating a convolution function on said angular range between said series of ambiguous angle error measurement values and a series of theoretical angle error measurement values of said receiving channels previously calculated and stored,
determining an angle of arrival of said received radioelectric signal as a function of an estimate of a maximum of said calculated convolution function.

2. The method according to claim 1 , including, before calculating and storing a series of ambiguous angle error measurement values, detecting and separating received radioelectric signals by emitting source.

3. The method according to claim 1 , wherein said series of theoretical angle error measurement values of said receiving channels includes a number of values corresponding to a predetermined angular sampling pitch, the method further including, before calculating a convolution function, re-sampling ambiguous angle error measurement values to obtain a series of ambiguous angle error measurement values of equal angular sampling pitch and of same number of values as said series of theoretical angle error measurement values.

4. The method according to claim 1 , including a first phase for calculating and storing said theoretical angle error measurement values for said receiving channels.

5. The method according to claim 4 , wherein said first phase comprises:
obtaining receiving amplitude measurements on each of the receiving channels for a plurality of angular values, of predetermined angular pitch, to obtain said first antenna diagram and second antenna diagram,
processing the first antenna diagram to obtain a synthetic antenna diagram, each amplitude value of the synthetic antenna diagram corresponding to a given angular value being equal to the maximum between the value of the first antenna diagram and the amplitude value of the second antenna diagram corresponding to said angular value.

6. The method according to claim 5 , further comprising calculating theoretical angle error measurement values consisting of calculating, for each angular value, the ratio between the amplitude value of the second antenna diagram corresponding to said angular value and the amplitude value of said synthetic antenna diagram corresponding to said angular value.

7. The method according to claim 1 , wherein each antenna diagram includes a main lobe centered on a radioelectric axis of the antenna, two secondary lobes surrounding said main lobe and diffuse lobes surrounding said secondary lobes, said angular range being chosen so as to comprise said main lobe, said secondary lobes and at least one diffuse lobe on either side of the radioelectric axis of the antenna.

8. The method according to claim 1 , implemented in an antenna receiving system with a monopulse-type antenna including two receiving channels, the first receiving channel being a sum channel and the second receiving channel being a difference channel.

9. A system for determining an angle of arrival of a radioelectric signal, including either one rotating antenna having at least two receiving channels, or two rotating antennas with a same rotation speed each having a receiving channel,
a first receiving channel having a first antenna diagram and a second receiving channel having a second antenna diagram, said first and second antenna diagrams being different,
said first and second receiving channels being connected to an electronic computing device including at least one processor configured for:
calculating and storing a series of ambiguous angle error measurement values obtained from receiving amplitude values of a radioelectric signal coming from an emitting source on said first and second receiving channels, said radioelectric signal being received on said first and second receiving channels by the one or more rotating antennas over a predetermined angular range, each angle error measurement value being representative of a ratio between receiving amplitude values on said first and second receiving channels, and corresponding to an angular deviation relative to a reference angular value;

wherein the calculation of a series of ambiguous angle error measurement values comprises:
obtaining receiving amplitude values on said first and second receiving channels, each amplitude value being associated with an angular value;
for the first receiving channel, for each angular value, calculating a so-called synthetic receiving amplitude value, equal to a maximum between the receiving amplitude value on the first receiving channel and the receiving amplitude value on the second receiving channel;
for each angular value, calculating an ambiguous angle error measurement value by obtaining the ratio between the receiving amplitude value on the second receiving channel and the corresponding synthetic receiving amplitude value;

the processor further being suitable for implementing modules configured for:
calculating a convolution function on said angular range between said series of ambiguous angle error measurement values and a series of theoretical angle error measurement values of said receiving channels previously calculated and stored,
determining an angle of arrival of said received radioelectric signal as a function of an estimate of a maximum of said calculated convolution function.

Assignees

• Thales Sa

Inventors

• Cornic Pascal
• Porez Nicolas
• Garrec Patrick

Classifications

• G01S3/32 Primary

  derived from different combinations of signals from separate antennas, e.g. comparing sum with difference · CPC title

• G01S3/48 Primary

  the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured · CPC title

• G01S3/60

  Broad-beam systems producing in the receiver a substantially sinusoidal envelope signal of the carrier wave of the beam, the phase angle of which is dependent upon the angle between the direction of the transmitter from the receiver and a reference direction from the receiver, e.g. cardioid system · CPC title

• G01S5/12

  by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial · CPC title