Methods and apparatus for detection system having fusion of radar and audio data

1. A method of locating a weapon, comprising:

detecting a weapon firing event with an audio sensor system, the detected weapon firing event indicative of a detected firing of the weapon and indicative of a detected time of the weapon firing event;

detecting a projectile fired from the weapon with a radar system;

employing a processor configured for:

correlating the weapon firing event detected by the audio sensor system with the detection of the projectile by the radar system to determine if the weapon firing event detected by the audio sensor system corresponds to the same projectile as that detected by the radar system, wherein the correlating comprises:

selecting a time difference threshold; and

relating the time difference threshold to a difference between the detected time of the weapon firing event detected by the audio sensor system and a time of the detection of the projectile by the radar system;

calculating a state vector associated with the projectile detection;

identifying a location of the weapon by backtracking the state vector to the detected time of the weapon firing event time; and

communicating the location of the weapon.

2. The method of claim 1 , further comprising generating a common time base for the weapon firing event and for the projectile detection.

3. The method of claim 1 , wherein the audio sensor system comprises an audio sensor.

4. The method of claim 1 , wherein the audio sensor system is directional and provides at least one of an azimuth angle of the detected weapon firing event or an elevation angle of the detected weapon firing event.

5. The method of claim 1 , wherein the step of detecting the weapon firing event with the audio sensor system comprises detecting the weapon firing event by direct path detection of audio generated by the weapon firing event.

6. A method of locating a weapon, comprising:

detecting a weapon firing event with an audio sensor system, the detected weapon firing event indicative of a detected firing of the weapon and indicative of a detected time of the weapon firing event;

detecting a projectile fired from the weapon with a radar system;

employing a processor configured for:

correlating the weapon firing event detected by the audio sensor system with the detection of the projectile by the radar system to determine if the weapon firing event detected by the audio sensor system corresponds to the same projectile as that detected by the radar system, wherein the correlating comprises:

selecting a time difference threshold; and

relating the time difference threshold to a difference between a time predicted by the state vector when backtracked to a terrain and the detected time of the weapon firing event detected by the audio sensor system;

calculating a state vector associated with the projectile detection;

identifying a location of the weapon by backtracking the state vector to the detected time of the weapon firing event time; and

communicating the location of the weapon.

7. A method of locating a weapon, comprising:

detecting a weapon firing event with an audio sensor system, the detected weapon firing event indicative of a detected firing of the weapon and indicative of a detected time of the weapon firing event;

detecting a projectile fired from the weapon with a radar system;

employing a processor configured for:

correlating the weapon firing event detected by the audio sensor system with the detection of the projectile by the radar system to determine if the weapon firing event detected by the audio sensor system corresponds to the same projectile as that detected by the radar system, wherein the correlating comprises:

selecting a position difference threshold; and

relating the position difference threshold to a difference between a location predicted by the state vector when backtracked to a terrain and a location predicted by the state vector when backtracked to the detected time of the weapon firing event detected by the audio sensor system;

calculating a state vector associated with the projectile detection;

identifying a location of the weapon by backtracking the state vector to the detected time of the weapon firing event time; and

communicating the location of the weapon.

8. A method of locating a weapon, comprising:

detecting a weapon firing event with an audio sensor system, the detected weapon firing event indicative of a detected firing of the weapon and indicative of a detected time of the weapon firing event;

detecting a projectile fired from the weapon with a radar system;

employing a processor configured for:

correlating the weapon firing event detected by the audio sensor system with the detection of the projectile by the radar system to determine if the weapon firing event detected by the audio sensor system corresponds to the same projectile as that detected by the radar system, wherein the correlating comprises:

selecting an angle difference threshold; and

relating the angle difference threshold to a difference between an angle to the projectile identified by the radar system and an angle to the weapon identified by the audio sensor system;

calculating a state vector associated with the projectile detection;

identifying a location of the weapon by backtracking the state vector to the detected time of the weapon firing event time; and

communicating the location of the weapon.

9. A weapon locating system, comprising:

an audio sensor system configured to detect a weapon firing event, the detected weapon firing event indicative of a detected firing of the weapon and indicative of a detected time of the weapon firing event;

a radar system configured to detect a projectile fired from the weapon;

a processor configured to:

correlate the weapon firing event detected by the audio sensor system with the detection of the projectile by the radar system to determine if the weapon firing event detected by the audio sensor system corresponds to the same projectile as that detected by the radar system, wherein the correlating comprises:

selecting a time difference threshold; and

relating the time difference threshold to a difference between the detected time of the weapon firing event detected by the audio sensor system and a time of the detection of the projectile by the radar system; and

calculate a state vector associated with the projectile detection and to backtrack the state vector to the detected time of the weapon firing event to identify the location of the weapon; and

a communication system configured to communicate the location of the weapon.

10. An article, comprising:

at least one computer-readable medium containing non-transitory stored instructions that enable a machine to perform:

detecting a weapon firing event with an audio sensor system, the detected weapon firing event indicative of a detected firing of the weapon and indicative of a detected time of the weapon firing event;

detecting a projectile fired from the weapon with a radar system;

correlating the weapon firing event detected by the audio sensor system with the detection of the projectile by the radar system to determine if the weapon firing event detected by the audio sensor system corresponds to the same projectile as that detected by the radar system, wherein the correlating comprises:

selecting a time difference threshold; and

relating the time difference threshold to a difference between the detected time of the weapon firing event detected by the audio sensor system and a time of the detection of the projectile by the radar system;

calculating a state vector associated with the projectile detection;

identifying a location of the weapon by backtracking the state vector to the detected time of the weapon firing event time; and

communicating the location of the weapon.

11. The method of claim 1 , further including receiving data from an optical sensor system to identify the location of the weapon.

12. The system of claim 9 , further including an optical sensor system coupled to the radar system.