Optimization of radar resources

• US 7,898,466 B1
• Filed: 12/08/2008
• Issued: 03/01/2011
• Est. Priority Date: 12/08/2008
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Vosbikian, Tamara A., Malakian, Kourken
• Primary Examiner(s): Sotomayor; John B
• Application Number:
  US12/329,991
• Time in Patent Office: 813 Days
• Field of Search: 342 95- 97, 342/107, 342/133, 342139-141, 342/195
• US Class Current: 342/95
• CPC Class Codes: G01S 13/426 Scanning radar, e.g. 3D radar G01S13/66 takes precedence
• CPC Class Codes: G01S 13/726 Multiple target tracking
• CPC Class Codes: G01S 7/295 Means for transforming co-ordinates or for evaluating data, e.g. using computers

Abstract

The radar tracking or pulse refresh rate is calculated for a target. The refresh rate is selected which makes a sum equal to a predetermined fraction of the radar beamwidth, where the sum is the sum of the bias error and a multiplicative product. The multiplicative product is the product of the random error multiplied by a number associated with the containment probability of the total error.

Claims

1. A method for determining timing of radar tracking pulses in a pulsed radar system operable in at least a tracking mode, and having known radar beamwidth, said method comprising the steps of:

determining a radar range of the target and an angle accuracy in the tracking mode;

determining bias error attributable to a maneuver of said target, random error in a sensed target angle, and probability of containment of a cumulative error, where the cumulative error comprises a combination of the error attributable to a maneuver and the random error;

from said bias error, random error, and probability of containment, determining a value of tracking refresh rate for the target which makes a sum of said bias error and a product of said random error multiplied by a number associated with the containment probability of the cumulative error equal to a predetermined fraction of said known radar beamwidth.

2. A method according to claim 1, wherein said step of determining a value of tracking refresh rate for the target comprises the step of determining a value of tracking refresh rate for a target which makes the sum of said bias error and said random error along said bias error and the product of said random error multiplied by a number associated with the containment probability of the cumulative error equal to one-half said known radar beamwidth.

3. A method for selection of the timing between successive tracking pulses in a radar system tracking, with the aid of a Kalman filter, a target having acceleration A and at a range r, where the radar system has a beamwidth BW at a given relative fractional power level k, and standard deviation of the measurement error σ

_m, said method comprising the steps of;

calculating lag time τ

of the Kalman filter which minimizes target velocity, and determining a nonlinear equation F(T) and its derivative F′

(T) with respect to a radar tracking pulse time interval T;

using an iterative Newton-Raphson numeric method, determining the value of radar tracking pulse time interval T, to within a predetermined accuracy; and

transmitting radar tracking pulses toward the target at the calculated value of radar tracking pulse time interval T.

4. A method according to claim 3, wherein said step of calculating the Kalman filter lag time τ

which minimizes target velocity, comprises the step of calculating

5. A method according to claim 3, wherein said step of determining a nonlinear equation F(T) and its derivative F′

(T) with respect to T includes the steps (a) of calculating;

6. A method for determining the timing of radar tracking pulses in a pulsed radar system operable in at least a tracking mode and having known or predetermined radar beamwidth, said method comprising the steps of:

determining a radar range of the target and an angle accuracy in the tracking mode;

determining bias error attributable to a maneuver of the target, a random error in sensed target angle, and a probability of containment of cumulative error;

from said bias error, random error, and probability of containment, determining a value of tracking refresh rate for the target which makes a sum equal to a predetermined fraction of said radar beamwidth, where said sum is a sum of said bias error and a multiplicative product, and said multiplicative product is a product of said random error multiplied by a number associated with the containment probability of the cumulative error.

7. A system for determining timing of radar tracking pulses in a pulsed radar system operable in at least a tracking mode, and having known radar beamwidth, comprising

a processor executing instructions to perform the following steps:

determining a radar range of the target and an angle accuracy in the tracking mode;

determining bias error attributable to a maneuver of said target, random error in a sensed target angle, and probability of containment of a cumulative error, where the cumulative error comprises a combination of the error attributable to a maneuver and the random error;

from said bias error, random error, and probability of containment, determining a value of tracking refresh rate for the target which makes a sum of said bias error and a product of said random error multiplied by a number associated with the containment probability of the cumulative error equal to a predetermined fraction of said known radar beamwidth.

8. A system according to claim 7, wherein, said step of determining a value of tracking refresh rate for the target comprises the step of determining a value of tracking refresh rate for a target which makes the stun of said bias error and said random error along said bias error and the product of said random error multiplied by a number associated with the containment probability of the cumulative error equal to one-half said known radar beamwidth.

9. A system for selection of the timing between successive tracking pulses in a radar system tracking, with the aid of a filter, a target having acceleration A and at a range r, where the radar system has a beamwidth BW at a given relative fractional power level k, and standard deviation of the measurement error σ

_m, said system comprising;

a processor executing instructions for performing the steps of

calculating lag time τ

of the filter which minimizes target velocity, and determining a nonlinear equation F(T) and its derivative F′

(T) with respect to a radar tracking pulse time interval T;

using an iterative Newton-Raphson numeric method, determining the value of radar tracking pulse time interval T, to within a predetermined accuracy; and

transmitting radar tracking pulses toward the target at the calculated value of radar tracking pulse time interval T.

10. A system according to claim 9, wherein the filter comprises a Kalman filter.

11. A system according to claim 9, wherein said step of calculating the filter lag time τ

which minimizes target velocity comprises the further step of calculating

12. A system according to claim 9, wherein said step of determining a nonlinear equation F(T) and its derivative F′

(T) with respect to T includes the steps;

(a) of calculating;