METHODS AND SYSTEMS FOR ENCODED BROADCASTING AND ANTENNA RECEPTION, PARTICULARLY FOR RADAR

• US 20110109498A1
• Filed: 06/30/2009
• Published: 05/12/2011
• Est. Priority Date: 07/03/2008
• Status: Active Grant

• Current Assignee: ANTHEOP
• Original Assignee: ANTHEOP
• Inventors: Goutelard, Claude
• Granted Patent: US 9,885,783 B2
• Time in Patent Office: Days
• US Class Current: 342/146
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/284 using coded pulses
• CPC Class Codes: G01S 13/48 using multiple beams at emission or reception

Abstract

To reduce radar cells and to improve the detection of a radar system, particularly a high-frequency surface wave radar (HFSWR), the broadcast system (SEM) is capable of broadcasting basic orthogonal signals two by two and each orthogonal to itself, temporally shifted to form, respectively, broadcast radiation patterns, each including main radiation lobes (L₁ , LP_N) alternating with secondary lobes, the main lobes associated with the basic signals being substantially juxtaposed in space. The receiving system (SRE) is capable of forming as many reception patterns in a monitored receiving area (ZR) as cells (CES_n'"'"'m) contained in the receiving area that are covered by main radiation lobes (LP_n) from one of the broadcast radiation patterns and located at a bistatic distance from the broadcast and receiving systems.

Claims

1. A method for emitting basic signals having orthogonality properties by emission antennas in an emission system and receiving the basic signals by several reception antennas in a reception system, comprising:

forming emission radiation charts for emitting respectively basic signals for all the emission antennas, each emission. radiation chart being associated with a respective basic signal to be emitted by all the emission antennas and comprising the main radiation lobes alternating with secondary radiation lobes, the main radiation lobes of the emission radiation charts substantially alternating and juxtaposed in the space, and

forming reception radiation charts in a reception area so as to receive the basic signals by each one of the reception antennas, the number of the reception radiation charts being at least equal to the number of cells being contained in the reception area, that arc covered by the main radiation lobes of one of the emission radiation charts and being located at a given bistatic distance from the emission and reception systems.

2. The method according to claim 1, wherein the basic signals are orthogonal. two by two.

3. The method according to claim 1, wherein each basic signal is orthogonal to itself being offset in time.

4. The method according to claim 1, comprising successive and cyclic emissions of basic signals.

5. The method according to claim 1, wherein the reception charts cover the reception area.

6. The method according to claim 5, wherein at least one of the reception charts has several main lobes alternating with secondary radiation lobes.

7. The method according to claim 1, comprising in the reception system:

weighting the signals captured by the reception antennas, the signal captured by a reception antenna being weighted so as to produce as many weighted signals as reception radiation charts, and

discriminating in basic signal and bistatic distance in the set of weighted signals for discriminating, on the one hand, cells having a constant bistatic distance, on the other hand, for a given bistatic distance, cells associated with one of the basic signals able to be discriminated by their orthogonality properties.

8. Emission and reception systems comprising several emission antennas for emitting basic signals having orthogonality properties and several reception antennas for receiving the basic signals, wherein:

the emission system comprises means for forming emission radiation charts for emitting respectively basic signals for all the emission antennas, each emission radiation chart being associated with a respective basic signal for emitting by all the emission antennas and comprising main radiation lobes alternating with secondary radiation lobes, the main radiation lobes of the emission radiation charts substantially alternating and being juxtaposed in the space, and

the reception system comprises means for forming reception radiation charts in a reception area so as to receive the basic signals by each one of the reception antennas, the number of reception radiation charts being at least equal to the number of cells contained in the reception area, that are covered by the main radiation lobes of one of the emission radiation charts and that are located at a given bistatic distance from the emission and reception systems.

9. The emission and reception systems according to claim 8, wherein the reception system comprises:

means for weighting signals captured by the reception antennas, the signal captured by a reception antenna being weighted so as to produce as many weighted signals as reception radiation charts, and

means for discriminating in basic signal and bistatic distance in the set of weighted signals, on the one hand, cells having a constant bistatic distance, on the other hand, for a given bistatic distance, cells associated with one of the basic signals able to be discriminated by their orthogonality properties.

10. Computer programs able to be implemented respectively in an emission system comprising several emission antennas for emitting basic signals having orthogonality properties and in a reception system comprising several reception antennas for receiving the basic signals, said programs comprising when the programmes are carried out in the emission system and the reception system, control steps of:

forming emission radiation charts for emitting respectively the basic signals by all the emission antennas, each emission radiation chart being associated with a respective basic signal to emit by all the emission antennas and comprising main radiation lobes alternating with secondary radiation lobes, the main radiation lobes of the emission radiation charts substantially alternating and juxtaposed in the space, and

forming reception radiation charts in a reception area so as to receive the basic signals by each one of the reception antennas, the number of reception radiation charts being at least equal to the number of cells contained in the reception area, that are covered by the main radiation lobes of one of the emission radiation charts and that are located at a given bistatic distance from the emission and reception systems.