초록 ▼

Systems and methods for locating the shooter of supersonic projectiles based on shockwave-only measurements are described. Muzzle blast signals are neither sought nor required. The system uses at least five, preferably seven, acoustic sensors that are spaced apart at least 1 meter. The sensor signal

Systems and methods for locating the shooter of supersonic projectiles based on shockwave-only measurements are described. Muzzle blast signals are neither sought nor required. The system uses at least five, preferably seven, acoustic sensors that are spaced apart at least 1 meter. The sensor signals are acquired with a time resolution in the order of microseconds and processed to find and disambiguate the shockwave arrival angle unit vector. Two different Time-Difference-Of-Arrival (TDOA) measurement techniques are described, with one technique using counters in each signal channel and the other technique using cross-correlation between signal channels. A genetic algorithm can be used to efficiently disambiguate the results.

대표청구항 ▼

What is claimed is: 1. A method for disambiguating a projectile trajectory from shockwave-only signals, comprising: measuring at least an initial portion of the shockwave-only signals at five or more spaced acoustic sensors forming an antenna; determining from the measured initial portion of the s

What is claimed is: 1. A method for disambiguating a projectile trajectory from shockwave-only signals, comprising: measuring at least an initial portion of the shockwave-only signals at five or more spaced acoustic sensors forming an antenna; determining from the measured initial portion of the shockwave-only signals Time-Differences-Of-Arrival (TDOA) for sensor pairs; applying a genetic algorithm to an initial chromosome, that comprises projectile trajectory assumptions, for a predefined number of generations; computing residuals for solutions obtained with the chromosomes from the genetic algorithm; performing a gradient search on a solution having a smallest residual and on its ambiguous alternate solution; and if a ratio of the solution having the smallest residual and its ambiguous alternate solution is greater than a predefined value, designating the solution having the smallest computed residual as the disambiguated projectile trajectory. 2. The method of claim 1, wherein the predefined value of the ratio is approximately 2. 3. The method of claim 1, wherein the chromosome comprises a 4-tuple having elements selected from the group consisting of shooter azimuth, shooter elevation, missed azimuth and missed elevation. 4. The method of claim 1, wherein applying a genetic algorithm comprises applying crossover and mutation operators. 5. The method of claim 4, wherein the crossover operator comprises crossover azimuth and crossover missed azimuth operators. 6. The method of claim 5, wherein the crossover azimuth operator exchanges shooter and trajectory azimuth between two chromosomes. 7. The method of claim 5, wherein the crossover missed azimuth operator exchanges missed azimuth and missed elevation between two chromosomes. 8. The method of claim 4, wherein the mutation operator comprises field-mutation, incremental mutation, flip mutation, and no mutation. 9. The method of claim 8, wherein the field-mutation operator replaces a chromosome field with a randomly selected value. 10. The method of claim 8, wherein the incremental mutation operator induces small mutations in all fields of a chromosome. 11. The method of claim 10, wherein the small mutation operator comprises changes in all fields of a chromosome of less than 짹2째 in shooter azimuth and elevation, and less than 짹0.5째 for missed azimuth and elevation. 12. The method of claim 10, wherein the flip-mutation operator comprises changing the solution having a smallest residual into its ambiguous alternate solution. 13. The method of claim 10, wherein the flip-mutation operator comprises leaving a chromosome unaltered. 14. The method of claim 1, wherein determining a Time-Difference-Of-Arrival (TDOA) for a sensor pair comprises performing a cross-correlation between shockwave signals detected at the sensor pairs and selecting the TDOA that produces the smallest computed residual.