Determination of jammer directions using multiple antenna beam patterns

• US 6,084,540 A
• Filed: 07/20/1998
• Issued: 07/04/2000
• Est. Priority Date: 07/20/1998
• Status: Expired due to Term

• Current Assignee: F Poszat Hu LLC (Intellectual Ventures LLC)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Yu, Kai-Bor
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US09/122,206
• Time in Patent Office: 715 Days
• Field of Search: 342/13-19, 342/147, 342/175, 342/195, 342/378-385, 342/417, 342/428, 342/357.01
• US Class Current: 342/17
• 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: G01S 3/28 using amplitude comparison of signals derived simultaneously from receiving antennas or antenna systems having differently-oriented directivity characteristics
• CPC Class Codes: G01S 7/36 Means for anti-jamming , e.g. ECCM, i.e. electronic counter-counter measures
• CPC Class Codes: H01Q 3/2611 Means for null steering; Adaptive interference nulling
• CPC Class Codes: H04K 2203/32 including a particular configuration of antennas
• 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

Abstract

A radar or GPS receiving system uses an antenna array to produce multiple antenna beams directed toward multiple targets or spacecraft. Stand-off jammers produce signals which tend to be received on the sidelobes of the antenna beams and to disrupt system operation. An array of autonomous or adaptive nullers process the received signals to produce weights which adjust the antenna nulls to direct them toward the jammers. The antenna nulls of one beam pattern are compared with the nulls of other beam patterns. Normal between-sidelobe nulls will not occur at the same angle on all of the patterns, but those nulls generated by the nullers will occur at the same angle. The directions to the jammers are deemed to be those directions in which all beam patterns have nulls.

Claims

1. A radar system, comprising:

at least one array antenna, for generating multiple directive beam patterns during an interval in which jammer signals are present in fixed directions, each of said directive beam patterns being associated with sidelobe nulls;

transmitting means for generating radar transmission signals for transmission toward targets, and receiving means coupled to said at least one array antenna, for receiving reflected signals, over at least some of said directive beams, from at least one of said targets;

radar signal processing means coupled to said transmitting and receiving means, for processing information relating to said transmission and reflected signals, for generating display information relating to said targets;

a plurality of adaptive jammer nulling arrangements coupled to said receiving means and to control said array antenna, for adjusting said antenna beam patterns of said array antenna in a manner which produces a beam null directed toward each said jammer, for thereby reducing the effect of operation of said jammer on said radar system; and

jammer direction determination means coupled to said jammer nulling arrangements, for comparing the directions of said nulls produced by each of said jammer nulling arrangements, and for deeming those directions in which nulls occur in all of said directive antenna patterns to be the directions of said jammers.

2. A method for detecting the locations of targets and the directions of jammers, said method comprising the steps of:

transmitting radar transmission signals toward a target;

with a controllable array antenna, receiving reflected signals from said target;

controlling the directive pattern of said controllable array antenna in such a manner as to generate at least one main lobe for each of a plurality of independently directed directive patterns;

processing said received signals to identify a target and determine its location;

in the presence ofjamming signals, processing said received signals in such a manner as to produce signals for modifying said plurality of directive patterns to direct a directivity null of each of said directivity patterns toward the source of said jamming signals; and

comparing a plurality of said directivity patterns with each other, and deeming the direction of a source of said jamming signals to be in that direction in which a null occurs for all of said plurality of directivity patterns.

3. A global positioning receiver, comprising:

at least one array antenna, for generating antenna beam patterns, which beam patterns include multiple directive beams during an interval in which a jammer signal is present at a fixed location, each of said directive beams being associated with sidelobe nulls;

receiving and control means coupled to said at least one array antenna, for directing said directive beams toward global positioning satellites, and for receiving global positioning signals from said global positioning satellites;

processing means coupled to at least said receiving means, for processing information relating to said global positioning signals, for generating display information relating to the position of said global positioning receiver;

a plurality of adaptive jammer nulling arrangements coupled to said receiving and control means, for adjusting the antenna beam patterns of said array antenna in a manner which produces a beam null directed toward each jammer, for thereby reducing the effect of operation of the jammer on said global positioning receiver; and

jammer direction determination means coupled to said jammer nulling arrangements, for comparing the directions of said nulls produced by each of said jammer nulling arrangements, and for deeming those directions in which nulls occur in all of said jammner nulling arrangements to be the directions of said jammers.