System and method for reduction of point of origin errors
A method of using a discriminant analysis and Kalman filter cascade to improve the accuracy of point of origin solutions. Tracking information about a potential target is utilized by an initial discrimination function to classify the target as a projectile. Using that information, the output of a first Kalman filter is fed into an additional discrimination function to further classify the type or sub-class of the projectile. A second Kalman filter can employ type-specific information to obtain a point of origin solution with increased efficiency and accuracy.
1. A method for extrapolating the point of origin of a projectile, the method comprising:
receiving, at a processor, data about a target from a radar;
classifying said target by performing a first discriminant function analysis of said received data using said processor;
performing, by said processor, a second discriminant function analysis of the analyzed data to create a first output comprising information about said radar target, wherein said second discriminant function is only performed if said first discriminant function classifies said target as a projectile;
calculating at least a first value of said projectile by performing, using said processor, a first Kalman filter algorithm using at least the data from said second discriminant function analysis;
performing, by said processor, a third discriminant function analysis of said at least a first value of said projectile to create a second output;
performing, by said processor, a second Kalman filter algorithm using at least said first value of said projectile to create a third output; and
using said third output to extrapolate a point of origin of said target.
2. The method of claim 1 , wherein said method further comprises:
predicting a point of impact.
3. The method of claim 1 , wherein said method further comprises:
sending at least said extrapolated point of origin to a downstream application.
4. The method of claim 3 , wherein said downstream application is a warning system.
5. The method of claim 3 , wherein said downstream application is a counter-measure system.
6. The method of claim 1 , wherein the step of calculating at least a first value of said projectile by performing a first Kalman filter algorithm comprises the steps of:
estimating at least an initial state of position and at least an initial state of velocity by fitting the received data into a quadratic curve;
initializing the ballistic coefficient to a constant value; and
computing the variance for at least a first radar coordinate.
7. The method of claim 1 , wherein said method further comprises:
measuring at least a first environmental variable, wherein said environmental variable is used by said first or second Kalman filter algorithm.
8. The method of claim 7 , wherein said environmental variable is wind speed.
9. The method of claim 8 , wherein said environmental variable is selected from the group consisting of wind speed, wind direction, air temperature, air density, and air pressure.
10. The method of claim 1 , wherein said method further comprises:
calculating at least a first radar cross-section, wherein said at least first radar cross-section is used in said third discriminant function analysis.
11. The method of claim 1 , wherein said second output comprises information about the target's caliber.
12. The method of claim 1 , wherein said Kalman filter algorithm comprises a type-specific ballistic model.
13. The method of claim 1 , wherein said Kalman filter algorithm comprises a type-specific drag model.
14. A method for extrapolating the point of origin of a projectile, the method comprising:
receiving, at a processor, data about a target from a radar;
performing, by said processor, a first discriminant function analysis of the received data to create a first output comprising information about said radar target;
calculating at least a first value of said projectile by performing, by said processor, a first Kalman filter algorithm using at least the data from said first discriminant function analysis;
performing, by said processor, a second discriminant function analysis of said at least a first value of said projectile to create a second output;
performing, by said processor, a second Kalman filter algorithm using at least said first value of said projectile to create a third output; and
using said third output to extrapolate a point of origin of said projectile.
15. The method of claim 14 , wherein said method further comprises:
predicting a point of impact.
16. The method of claim 14 , wherein said method further comprises:
sending at least said extrapolated point of origin to a downstream application.
17. The method of claim 15 , wherein said method further comprises:
sending at least said point of impact to a downstream application.
18. The method of claim 14 , wherein said method further comprises:
measuring at least a first environmental variable, wherein said environmental variable is used by said first or second Kalman filter algorithm.
19. The method of claim 14 , wherein said method further comprises:
calculating at least a first radar cross-section, wherein said at least first radar cross-section is used in said second discriminant function analysis.
20. The method of claim 14 , wherein said first output comprises information about the target's caliber.