Array of UHF radar bases for protecting sensitive zones against intrusions

• US 8,446,311 B2
• Filed: 11/30/2010
• Issued: 05/21/2013
• Est. Priority Date: 12/01/2009
• Status: Expired due to Fees

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Ricci, Yves, Cavallari, Christian
• Primary Examiner(s): Keith, Jack W
• Assistant Examiner(s): BYTHROW, PETER M
• Application Number:
  US12/957,210
• Publication Number:
  US 20110254724A1
• Time in Patent Office: 903 Days
• Field of Search: 342/27, 342/28, 342/59
• US Class Current: 342/28
• CPC Class Codes: G01S 13/53 performing filtering on a single spectral line and associated with one or more range gates with a phase detector or a frequency mixer to extract the Doppler information, e.g. pulse Doppler radar G01S13/5244 takes precedence
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/0232 Avoidance by frequency multiplex

Abstract

A system for protecting sensitive zones includes detection bases disposed in such a way that each base performs the monitoring of a part of the limit of the protected zone. To each base n is allocated a frequency channel of width B′ centered on a frequency F_n. Each base comprises a plurality of UHF radars emitting pulses of spectral width B, with a high repetition frequency Fr. Each radar processes a fraction b₀ of the global Doppler band b₁ concerned. The emission frequencies of the various radars constituting one and the same base are defined in such a way that the gap between the emission frequency Fi of a radar of the base and the frequency F_n is less than the repetition frequency Fr and that the gap between the emission frequencies Fi and Fj of two radars of one and the same base is greater than (b₁+b₀)/2. The channel allocated to a base n as well as the emission frequencies allocated to the radars of this base are defined in such a way that, having regard to the position of the base, none of the radars constituting the base concerned is liable to be disturbed from a radioelectric point of view by the radars of the other bases.

Claims

1. A radar detection device comprising:

a base n to which is allocated a nominal frequency Fn and a frequency band of width B′

, on which are located pulsed Doppler UHF radars, of high repetition frequency Fr, each radar operating in a frequency band B, centred on an emission frequency Fi;

wherein, each radar i utilizing a Doppler spectral band b₀ around its emission frequency Fi, the number N of radars that the base can comprise and the emission frequency Fi of each radar i are defined in such a way that the gap (F_i−

F_n) is smaller in absolute value than the difference (Fr−

b₀)/2 and is not a sub-multiple of Fr/2;

a global Doppler spectral band b₁ corresponding to a maximum span of speeds being defined, the gap between the emission frequencies Fi and Fj of any two radars i and j of the base is greater than (b₁+b₀)/2.

2. The device according to claim 1, wherein, for a given global Doppler spectral band b1, the number N of radars that a base can comprise is dependent on the ratio Fr/b₁.

3. The device according to claim 1, wherein the radars are arranged on the base in such a way as to cover a continuous aperture zone extending over substantially 180°

.

4. The device according to claim 3, wherein angular sectors covered by the various radars exhibit overlap zones.

5. The device according to claim 1, wherein the radars are arranged so as to cover distinct sectors surrounding a detection base.

6. The device according to claim 5, wherein the radars are arranged in such a way that, having regard to an angular sector that can be covered by a radar, a continuous aperture zone extending over substantially 360°

around the base is covered.

7. A radar system for detecting intrusions into a protected zone delimited by a line, the crossing of the line being considered to be an intrusion into the protected zone, comprising a plurality of detection bases according to claim 1, arranged in such a way as to cover in a continuous manner the limit of the protected zone over the whole of its length;

each base n operating in a spectral band B′

centred on a frequency F_n;

the frequency F_n allocated to a base n being defined in such a way that, having regard to the position of the base, none of the radars constituting the base concerned is liable to be impeded from a radioelectric point of view by the radars of the other bases.

8. The radar system according to claim 7, wherein, each base comprising M colocated UHF radars whose Doppler spectral band is such that, having regard to the repetition frequency Fr, a number N, which is a multiple of M, of radars can operate in one and the same frequency band, the system allocates one and the same frequency F to N/M detection bases, the detection bases operating in one and the same spectral band being arranged in such a way that the emission carried out by a base does not impair the detection capabilities of the other bases occupying the same spectral band B′

.