Single channel semi-active radar seeker

• US 8,274,425 B2
• Filed: 12/29/2010
• Issued: 09/25/2012
• Est. Priority Date: 12/29/2010
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Yeary, Mark B., Toplicar, James R., Doucette, Paul E., Foltz, Eleanor
• Primary Examiner(s): Sotomayor, John B
• Application Number:
  US12/981,401
• Publication Number:
  US 20120169524A1
• Time in Patent Office: 636 Days
• Field of Search: 342/62, 342 74- 77, 342 80- 81, 342/85, 342/90, 342 95- 97, 342125-126, 342131-135, 342139-141, 342147-154, 342156-158
• US Class Current: 342/62
• CPC Class Codes: F41G 7/2266 Systems comparing signals received from a base station and reflected from the target
• CPC Class Codes: F41G 7/2286 using radio waves
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/46 Indirect determination of position data
• CPC Class Codes: G01S 13/876 Combination of several spaced transponders or reflectors of known location for determining the position of a receiver G01S13/874 takes precedence
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 2013/462 using multipath signals
• CPC Class Codes: G01S 5/0273 using multipath or indirect path propagation signals in position determination
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems

Abstract

The disclosed approach provides a low-cost approach by employing a single channel receiver for a direction-finding missile, rather than a conventional four-channel system. It employs interferometry techniques. The proposed approach leverages orthogonal waveforms and pseudorandom noise (PN) codes. This is a low-cost approach for a single channel direction finding system by leveraging orthogonal waveforms and interferometric techniques.

Claims

1. A seeker comprising:

a single channel radio frequency (RF) receiver configured to convert a plurality of transmitted signals received by a single receiving antenna element into a corresponding plurality of received signals, the plurality of transmitted signals comprising mutually orthogonal transmitted waveforms from a corresponding plurality of spatially separated transmitting sources, each of the plurality of transmitted signals being received by the single receiving antenna element both directly from a respective one of the transmitting sources and indirectly from reflections off a target, the plurality of received signals comprising a corresponding plurality of received directly transmitted signals and a corresponding plurality of received reflected signals; and

a processor configured

to separate the plurality of received directly transmitted signals to track the seeker'"'"'s location and motion relative to the transmitting sources, and

to separate the plurality of received reflected signals to track the target'"'"'s location and motion relative to the seeker.

2. The seeker of claim 1, wherein a number of the plurality of transmitted signals is four.

3. The seeker of claim 1, further comprising a digital correlator for correlating each of the plurality of received signals whose corresponding said transmitted signals are synchronized to a common clock of the plurality of spatially separated transmitting sources.

4. The seeker of claim 1, further comprising a digital correlator for correlating each of the plurality of received signals against known Walsh sequences to segregate the received signals into corresponding contributions from each of the plurality of transmitted signals.

5. The seeker of claim 1, further comprising a digital correlator for correlating each of the plurality of received signals against a known pseudorandom noise sequence to segregate the received signals into corresponding contributions from each of the plurality of transmitted signals.

6. The seeker of claim 1, wherein the processor is further configured to communicate the tracked location and motion information to a guidance computer of an interceptor to allow the guidance computer to guide the interceptor to the target.

7. An interceptor comprising the seeker of claim 1.

8. An interceptor for intercepting a target from a launch platform comprising a plurality of spatially separated transmitting sources, the interceptor comprising:

a single receiving antenna element for receiving a corresponding plurality of transmitted signals from the plurality of spatially separated transmitting sources, the plurality of transmitted signals comprising mutually orthogonal transmitted waveforms, each of the plurality of transmitted signals being received by the single receiving antenna element both directly from a respective one of the transmitting sources and indirectly from reflections off the target; and

a seeker comprising;

a single channel radio frequency (RF) receiver configured to convert the plurality of transmitted signals received by the single receiving antenna element into a corresponding plurality of received directly transmitted signals and a corresponding plurality of received reflected signals; and

a processor configured

to separate the plurality of received directly transmitted signals to track the seeker'"'"'s location and motion relative to the transmitting sources, and

to separate the plurality of received reflected signals to track the target'"'"'s location and motion relative to the seeker.

9. The interceptor of claim 8, wherein a number of the plurality of transmitted signals is four.

10. A method of tracking a target by a seeker comprising a single channel radio frequency (RF) receiver connected to a single receiving antenna element, the method comprising:

receiving a plurality of transmitted signals by the single receiving antenna element, the plurality of transmitted signals comprising mutually orthogonal transmitted waveforms from a corresponding plurality of spatially separated transmitting sources, each of the plurality of transmitted signals being received by the single receiving antenna element both directly from a respective one of the transmitting sources and indirectly from reflections off the target;

converting by the single channel RF receiver the plurality of transmitted signals into a corresponding plurality of received directly transmitted signals and a corresponding plurality of received reflected signals;

separating the plurality of received directly transmitted signals to track the seeker'"'"'s location and motion relative to the transmitting sources; and

separating the plurality of received reflected signals to track the target'"'"'s location and motion relative to the seeker.

11. The method of claim 10, wherein a number of the plurality of transmitted signals is four.