Detection and location of radio frequency weapons from high altitude glider system

• US 7,948,426 B2
• Filed: 10/26/2009
• Issued: 05/24/2011
• Est. Priority Date: 10/26/2009
• Status: Active Grant

• Current Assignee: Southwest Research Institute
• Original Assignee: Southwest Research Institute
• Inventors: Wiebush, Le Moey Jr., Pevler, Alfred E., Van Rheeden, Donald R.
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Brainard; Timothy A
• Application Number:
  US12/605,439
• Publication Number:
  US 20110095933A1
• Time in Patent Office: 575 Days
• Field of Search: 342/13, 342/357.39
• US Class Current: 342/13
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence

Abstract

A method and system for detecting and locating RF weapons being used against aircraft. Large geographic regions may be defended by equipping a constellation of high-altitude airborne platforms with RF detectors, GPS receivers and a communications unit. The communications unit downlinks data indicating an RF weapon pulse and associated time and location data. From this data, a ground station performs a time difference of arrival (TDOA) location fix of the RF weapon.

Claims

1. A method of detecting and locating RF emissions weapons, comprising:

selecting a geographic region of protection;

deploying at least four aircraft to an altitude above commercial airline flight traffic lanes, each aircraft carrying a detection unit having at least an RF weapon detector, a GPS receiver, and a communications unit;

wherein the detection unit is programmed to time stamp detected RF weapon pulses and to associate GPS location data with the time of detection;

wherein the aircraft are configured to orbit above the geographic region;

monitoring data received from each aircraft at a ground station, the data from each aircraft indicating if an RF weapon pulse has been detected, and if so, the data further indicating the time of such detection and the location of the aircraft at that time;

using a computer-based analysis unit at the ground station to perform the following steps;

to calculate hyperbolic lines of position associated with the data from each aircraft;

to use the results of the preceding step and additional data representing the altitude of the aircraft and the terrain of the geographic region to calculate a best point estimate of the location of the RF weapon;

to calculate at least one probability containment region around the best point estimate; and

to display a map of at least part of the geographic region, the map graphically illustrating the containment region and the best point estimate.

2. The method of claim 1, wherein the aircraft are gliders.

3. The method of claim 2, wherein the deploying step is performed by using lighter-than-air balloons to lift the gliders to the desired altitude.

4. The method of claim 1, wherein the containment region is circular.

5. The method of claim 1, wherein the containment region is an ellipse.

6. A system for detecting and locating RF emissions weapons within a geographic region of protection, comprising:

at least four aircraft configured to orbit above the geographic region at an altitude above commercial airline flight traffic lanes, each aircraft carrying a detection unit having at least an RF weapon detector, a GPS receiver, and a communications unit;

wherein the detection unit is programmed, to time stamp detected RF weapon pulses, to associate GPS location data with the time of detection, and to transmit data representing the time of the pulse and the associated location via a downlink channel;

a ground station having computer-based equipment programmed to perform the following;

to monitor the downlink channel for data received from each aircraft at a ground station, the data from each aircraft indicating if an RF weapon pulse has been detected, and if so, the data further indicating the time of such detection and the location of the aircraft at that time;

to calculate hyperbolic lines of position associated with the data from each aircraft;

to use the results of the preceding step and additional data representing the altitude of the aircraft and the terrain of the geographic region to calculate a best point estimate of the location of the RF weapon;

to calculate at least one probability containment region around the best point estimate; and

to display a map of at least part of the geographic region, the map graphically illustrating the containment region and the best point estimate.

7. The system of claim 6, wherein the aircraft are gliders.

8. The system of claim 7, wherein lighter-than-air balloons are used to lift the gliders to the desired altitude.

9. The system of claim 6, wherein the containment region is circular.

10. The system of claim 6, wherein the containment region is an ellipse.