Directional warhead fuze

• US 5,359,934 A
• Filed: 09/19/1990
• Issued: 11/01/1994
• Est. Priority Date: 09/19/1990
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Crawford, Malcolm F., Chinchillo, A. Robert, Ivanov, Alex J., Goldberg, Ernest, Driscoll, James A., Linnehan, Richard P.
• Primary Examiner(s): Jordan, Charles T.
• Application Number:
  US07/584,681
• Time in Patent Office: 1,504 Days
• Field of Search: 102/214, 102/215, 102/213
• US Class Current: 102/214
• CPC Class Codes: F42C 13/04 operated by radio waves
• CPC Class Codes: G01S 13/4445 amplitude comparisons monopulse, i.e. comparing the echo signals received by an antenna arrangement with overlapping squinted beams

Abstract

A directional ordnance for a missile. The missile contains circuitry to determine the direction of a target relative to the missile and to selectively detonate directing charges to force the blast from the warhead towards the target. The circuitry for determining the direction of the target includes two transmit antennas, each transmitting a different pseudo noise sequence, and two receive antennas; each coupled to a receiver which can determine the level of each pseudo noise sequence at each receive antenna. The relative strengths of the different pseudo noise sequences tell the direction of the target relative to the transmit and receive antennas.

Claims

1. A missile comprising:

a) a first transmit antenna and a second transmit antenna;

b) means, coupled to the first-and second transmit antennas, for generating a first pseudo noise signal and a second pseudo noise signal;

c) a first receive antenna and a second receive antenna; and

d) means, coupled to the first and second receive antennas, for determining the levels of the first and second pseudo noise signals received at the first and second receive antennas.

2. The missile of claim 1 wherein the means for determining the levels of the pseudo noise signals comprises means for correlating the signals at the first and second receive antennas with the first and second pseudo noise sequences.

3. The missile of claim 1 additionally comprising means, responsive to the means for determining, for computing the direction of a target relative to the missile.

4. The missile of claim 3 additionally comprising means, coupled to the means for computing the direction of a target, for selectively firing at least one of a plurality of directing charges.

5. The missile of claim 4 wherein the means for computing direction comprises means for amplifying the signals received at the first and second receive antennas by a predetermined amount before the signals are applied to the means for computing direction.

6. The missile of claim 2 wherein the means for correlating comprises four correlators, each correlator having two inputs and one output wherein:

a) a first correlator has one input coupled to the means for generating the first pseudo noise sequence and one input coupled to the first receive antenna;

b) the second correlator has one input coupled to the means for generating the first pseudo noise sequence and one input coupled to the second receive antenna;

c) the third correlator has one input coupled to the means for generating the second pseudo noise sequence and one input coupled to the first receive antenna; and

d) the fourth correlator has one input coupled to the means for generating the second pseudo noise sequence and one input coupled to the second receive antenna.

7. The missile of claim 6 wherein the outputs of each of the four correlators is coupled to digital logic means for selecting the largest signal.

8. The missile of claim 7 wherein the output of each correlator is coupled to the digital logic means through a circuit comprising:

a) a switch having at least one pole and two throws, the pole being connected to a correlator and the first throw coupled to an input of the digital logic means; and

b) an amplifier having an input connected to the second throw and an output coupled to an input of the digital logic means.

9. The missile of claim 8 wherein the digital logic means also comprises means for selectively actuating the switches and for determining the direction of a target from the largest signal selected before and after the switches are actuated.

10. A method of controlling a missile comprising the steps of:

a) transmitting at least a first pseudo noise signal into a first region and transmitting a second pseudo noise signal into a second region;

b) receiving signals from at least a third region and from a fourth region;

c) comparing the pseudo noise sequences and the received signals to determine the strengths of each pseudo noise signal in each received signal; and

d) determining the direction of a target relative to the missile from the strength of each pseudo noise sequence in each received signal.

11. The method of controlling a missile of claim 10 wherein the step of determining the direction of a target comprises:

a) producing a plurality of signals, each signal indicating the level of one transmitted pseudo noise signal in one received signal; and

b) comparing the levels of the plurality of signals.

12. The method of controlling a missile of claim 11 wherein the step of determining the direction additionally comprises:

assigning a direction based on the difference between the one of the plurality of signals and a second one of the plurality of signals.

13. The method of controlling a missile of claim 12 wherein the step of assigning a direction comprises:

a) assigning a first direction when the difference between the largest of the plurality of signals anti the next largest of the plurality of signals exceeds a threshold; and

b) assigning a second direction when the difference between the largest of the plurality of signals and the next largest of the plurality of signals is below the threshold.

14. The method of controlling a missile of claim 13 additionally comprising the step of:

directing the force from an explosion in the assigned direction.

15. The method of controlling a missile of claim 11 wherein the step of producing a plurality of signals comprises:

correlating each transmitted pseudo noise signal with each received signal.

16. The method of controlling a missile of claim 10 additionally comprising the step of directing a cloud of shrapnel in the direction of the target.

17. A method of controlling a missile comprising:

a) transmitting at least;

(i) a first transmit signal into a first transmit region around the missile, the first transmit signal being transmitted in different direction in the first transmit region with different gains, the pattern of gains making a first transmit coverage pattern;

(ii) a second transmit signal into a second transmit region around the missile, the second transmit signal being transmitted in different direction in the second transmit region with different gains, the pattern of gains making a second transmit coverage pattern;

b) receiving at least;

(i) a first receive signal from a first receive region around the missile, the first receive signal being received from different directions in the first receive region with different gains, the pattern of gains making a first receive coverage pattern;

(ii) a second receive signal from a second receive region around the missile, the second receive region being received from different directions in the second receive region with different gains, the pattern of gains making a second receive coverage pattern;

c) determining, by processing the transmitted and received signals, the strengths of signals reflected from objects in at least four combined regions, each combined region having a combined coverage pattern with a gain in different directions given by the product of the gain of one transmit coverage pattern and one receive coverage pattern and each reflected signal having a strength proportional to the gain of the combined coverage in the direction of the object relative to the missile; and

d) computing the direction of the object relative to the missile from the determined strength of the reflected signals.

18. The method of claim 17 additionally comprising the step of detonating an explosive charge and directing the blast from the target in the direction of the object.

19. The method of claim 18 wherein the step of determining the strength of reflected signals comprises, for each combined region:

a) computing the correlation of one transmitted signal with one received signal; and

b) selecting the peak value of the computed correlation.

20. The method of claim 19 wherein the step of computing the direction comprises:

a) selecting, from the reflected signals from at least four combined regions, the strength of the reflected signal with the largest value and determining the strength of reflected signals from combined regions adjacent to the combined region from which the largest signal was reflected;

b) selecting, as the computed direction,

(i) the direction in the center of the combined region associated with the largest reflected signal when the strength of the largest reflected signal exceeds the strength of the reflected signals from adjacent combined regions by a predetermined treshold; and

(ii) the direction intermediate the center of the combined region associated with the largest reflected signal and the center of the combined region associated with the larger of the reflected signals from adjacent combined regions when the strength of the largest reflected signal does not exceed the strength of the reflected signals from adjacent combined regions by a predetermined threshold.

21. The method of claim 20 wherein the step of selecting the direction comprises amplifying reflected signals from adjacent combined regions by the predetermined threshold.