Anti- jamming method for spread-spectrum radio signal receivers

• US 20050078739A1
• Filed: 12/06/2002
• Published: 04/14/2005
• Est. Priority Date: 12/18/2001
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Korpet, Damien, Renard, Alain
• Granted Patent: US 7,386,034 B2
• Time in Patent Office: Days
• US Class Current: 375/148
• CPC Class Codes: G01S 19/21 Interference related issues ; Issues related to cross-correlation, spoofing or other methods of denial of service
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04K 3/228 Elimination in the received signal of jamming or of data corrupted by jamming interference suppression in receivers H04B1/10
• CPC Class Codes: H04K 3/90 related to allowing or preventing navigation or positioning, e.g. GPS

Abstract

The invention relates to the improving of the resistance to intentional or unintentional jamming, of a receiver of spread spectrum radio signals transmitted by polarized wave. It consists in furnishing the receiver (2) with an array antenna (1) composed of elementary antennas (1a to 1f) having at least one so-called matched output path MP sensitive to the polarization of the polarized wave used for the transmission, certain (1b, 1d, 1e, 1f, 1g) furthermore having a second so-called cross path CP sensitive to a polarization orthogonal to that of the polarized wave used for the transmission and in performing first individual antijamming processings by polarimetric filtering (3) on each of the elementary antennas (1b, 1d, 1e, 1f, 1g) with matched MP and cross CP output paths then, globally, at the level of the reception signals obtained and of the reception signals of the elementary antennas (1a, 1c) without cross output path CP utilized, a second general antijamming processing by spatial filtering (4). Moreover, the invention can integrate additional antijamming processings by temporal or spectral filtering.

Claims

1. An antijamming method for a receiver of spread spectrum radio signals transmitted by polarized wave, the receiver having a receive array antenna including elementary antennas having at least one matched output path MP, sensitive to the polarization of the polarized wave used for the transmission, certain elementary antennas, and having a second cross output path CP, sensitive to a polarization orthogonal to that of the polarized wave used for the transmission, the method comprising the steps of:

performing first individual antijamming processings by polarimetric filtering on each of the elementary antennas with matched MP and cross CP output paths so as to derive from each of them, by combining the signals picked up by their matched MP and cross CP output paths, a single reception signal having undergone a first degarbling, and

globally performing, at the level of reception signals originating from the first individual antijamming processings by polarimetric filtering and the reception signals picked up by the elementary antennas devoid of cross output paths CP utilized, a second general antijamming processing by spatial filtering so as to derive by combining these reception signals, a reception signal having undergone a new degarbling.

2. The method as claimed in claim 1, wherein the polarimetric and spatial antijamming processings are performed simultaneously by one and the same processing circuit.

3. The method as claimed in claim 1, wherein, the first individual antijamming processings by polarimetric filtering for linearly combining, in phase and in amplitude, the signals picked up on the matched MP and cross CP output paths of one and the same elementary antenna to obtain a minimum of energy after processing.

4. The method as claimed in claim 1, wherein the first individual antijamming processings by polarimetric filtering are done with the aid of polarimetric filters all having the same adjustment, which adjustment is determined in such a way as to obtain a minimum of energy after processing for the one, taken as reference, of the elementary antennas with matched and cross output paths.

5. The method as claimed in claim 1, wherein the first individual antijamming processings by polarimetric filtering are done independently of one another, with the aid of polarimetric filters adjusted individually in such a way as to obtain, each time, a minimum of energy after processing.

6. The method as claimed in claim 1, wherein the second general antijamming processing by linearly combining, by spatial filtering, in amplitude and in phase, the reception signals originating from the first individual antijamming processings by polarimetric filtering and the reception signals picked up by the elementary antennas devoid of cross output path CP utilized, with a view to electronic pointing of the receive array antenna giving the main lobe of its radiation pattern the form of a narrow beam pointing in the direction of the position of the emitter of the polarized wave used for the transmission of the spread spectrum radio signals.

7. The method as claimed in claim 1, wherein the second general antijamming processing by spatial filtering consists in linearly combining, in amplitude and in phase, the reception signals originating from the first individual antijamming processings by polarimetric filtering and the reception signals picked up by the elementary antennas devoid of cross output path CP utilized, with a view to creating nulls in the radiation pattern of the receive array antenna in the directions of the jammers.

8. The method as claimed in claim 1, wherein the second general antijamming processing by linearly combining using spatial filtering, in amplitude and in phase, the reception signals originating from the first individual antijamming processings by polarimetric filtering and the reception signals picked up by the elementary antennas devoid of cross output path CP utilized, with a view to creating nulls in the radiation pattern of the receive array antenna in the directions of the jammers, one of the elementary antennas with matched MP and cross CP output paths is regarded as a reference elementary antenna and the other elementary antennas of the array antenna as auxiliary elementary antennas and the coefficients of the linear combination are altered dynamically so that the signal resulting from the linear combination is decorrelated with the reception signals of which it is composed, with the exception of the reception signal originating from the reference elementary antenna after a first individual antijamming processing by polarimetric filtering.

9. The method as claimed in claim 1, wherein additional antijamming processings by temporal or spectral filtering are performed on each of the reception signals originating from the first individual antijamming processings by polarimetric filtering and the reception signals picked up by the elementary antennas devoid of cross output path CP utilized, upstream of the second general antijamming processing by spatial filtering.

10. The method as claimed in claim 1, wherein an additional antijamming processing by temporal or spectral filtering is performed after the second general antijamming processing by spatial filtering.

11. The method as claimed in claim 2, wherein, the first individual antijamming processings by polarimetric filtering for linearly combining, in phase and in amplitude, the signals picked up on the matched MP and cross CP output paths of one and the same elementary antenna to obtain a minimum of energy after processing.

12. The method as claimed in claim 2, wherein the first individual antijamming processings by polarimetric filtering are done with the aid of polarimetric filters all having the same adjustment, which adjustment is determined in such a way as to obtain a minimum of energy after processing for the one, taken as reference, of the elementary antennas with matched and cross output paths.

13. The method as claimed in claim 2, wherein the first individual antijamming processings by polarimetric filtering are done independently of one another, with the aid of polarimetric filters adjusted individually in such a way as to obtain, each time, a minimum of energy after processing.

14. The method as claimed in claim 2, wherein the second general antijamming processing by linearly combining using spatial filtering in amplitude and in phase, the reception signals originating from the first individual antijamming processings by polarimetric filtering and the reception signals picked up by the elementary antennas devoid of cross output path CP utilized, with a view to creating nulls in the radiation pattern of the receive array antenna in the directions of the jammers, one of the elementary antennas with matched MP and cross CP output paths is regarded as a reference elementary antenna and the other elementary antennas of the array antenna as auxiliary elementary antennas and the coefficients of the linear combination are altered dynamically so that the signal resulting from the linear combination is decorrelated with the reception signals of which it is composed, with the exception of the reception signal originating from the reference elementary antenna after a first individual antijamming processing by polarimetric filtering.

15. The method as claimed in claim 2, wherein additional antijamming processings by temporal or spectral filtering are performed on each of the reception signals originating from the first individual antijamming processings by polarimetric filtering and the reception signals picked up by the elementary antennas devoid of cross output path CP utilized, upstream of the second general antijamming processing by spatial filtering.

16. The method as claimed in claim 2, wherein an additional antijamming processing by temporal or spectral filtering is performed after the second general antijamming processing by spatial filtering.

17. An antijamming receiver, comprising:

a receive array antenna including elementary antennas having at least one matched output path MP, sensitive to the polarization of the polarized wave used for the transmission, some of said elementary antennas having a second cross output path CP, sensitive to a polarization orthogonal to that of a polarized wave used for the transmission, a filter for performing first individual antijamming processings by polarimetric filtering on each of the elementary antennas with matched MP and cross CP output paths so as to derive from each of them, by combining the signals picked up by their matched MP and cross CP output paths, a single reception signal having undergone a first degarbling, and

a filter for globally performing, at the level of reception signals originating from the first individual antijamming processings and reception signals picked up by said elementary antennas devoid of cross output paths CP utilized, a second general antijamming processing by spatial filtering so as to derive by combining these reception signals, a reception signal having undergone a new degarbling.

18. The antijamming receiver as claimed in claim 17, wherein the first individual antijamming processings by polarimetric filtering are done with the aid of polarimetric filters all having the same adjustment, which adjustment is determined in such a way as to obtain a minimum of energy after processing for the one, taken as reference, of the elementary antennas with matched and cross output paths.

19. The antijamming receiver as claimed in claim 17, wherein spatial filtering performs second general antijamming processing by linearly combining, in amplitude and in phase, the reception signals originating from the first individual antijamming processings by polarimetric filtering and the reception signals picked up by the elementary antennas devoid of cross output path CP utilized, with a view to electronic pointing of the receive array antenna giving the main lobe of its radiation pattern the form of a narrow beam pointing in the direction of the position of the emitter of the polarized wave used for the transmission of the spread spectrum radio signals.

20. The antijamming receiver as claimed in claim 19, wherein the second general antijamming processing by linearly combining using spatial filtering, in amplitude and in phase, the reception signals originating from the first individual antijamming processings by polarimetric filtering and the reception signals picked up by the elementary antennas devoid of cross output path CP utilized, with a view to creating nulls in the radiation pattern of the receive array antenna in the directions of the jammers, one of the elementary antennas with matched MP and cross CP output paths is regarded as a reference elementary antenna and the other elementary antennas of the array antenna as auxiliary elementary antennas and the coefficients of the linear combination are altered dynamically so that the signal resulting from the linear combination is decorrelated with the reception signals of which it is composed, with the exception of the reception signal originating from the reference elementary antenna after a first individual antijamming processing by polarimetric filtering.

21. The antijamming receiver as claimed in claim 17, wherein additional antijamming processings by temporal or spectral filtering are performed on each of the reception signals originating from the first individual antijamming processings by polarimetric filtering and the reception signals picked up by the elementary antennas devoid of cross output path CP utilized, upstream of the second general antijamming processing by spatial filtering.