Portable, iterative geolocation of RF emitters

• US 7,804,448 B2
• Filed: 11/09/2009
• Issued: 09/28/2010
• Est. Priority Date: 12/27/2006
• Status: Active Grant

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: TruePosition Incorporated
• Inventors: Anderson, Robert J., Lefever, Ronald, Bull, Jeffrey F.
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Mull; Fred H
• Application Number:
  US12/615,021
• Publication Number:
  US 20100052990A1
• Time in Patent Office: 323 Days
• Field of Search: 342463-465, 342/387, 342/450, 342/457, 342/357.14
• US Class Current: 342/387
• CPC Class Codes: G01S 5/0072 Transmission between mobile stations, e.g. anti-collision systems
• 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

Iterative geolocation of a stationary RF emitter through the use of TDOA may include the use of a single portable geolocation (e.g., TDOA) sensor, a pair of portable geolocation sensors and three of more portable geolocation sensors. Adding portable geolocation sensors to the iterative process reduces the constraints on the signals to be located as well as providing a reduction in the number of iterations required to obtain improved location accuracy.

Claims

1. A method for locating an emitter of interest (EOI) using at least one portable geolocation sensor, comprising:

at a first location, using a first portable geolocation sensor to receive, time stamp and store EOI transmissions during a first period of time;

moving the first portable geolocation sensor to a second location;

at the second location, using the first portable geolocation sensor to receive, time stamp and store EOI transmissions during a second period of time; and

using a stable frequency reference to characterize the timing and frequency stability of the EOI transmissions.

2. A method as recited in claim 1, further comprising computing the location of the EOI using data representative of the EOI transmissions stored during said first and second periods of time.

3. A system for use in locating an emitter of interest (EOI), comprising:

a portable receiver configured to receive, time stamp and store EOI transmissions during a first period of time at a first location, and to receive, time stamp and store EOI transmissions during a second period of time at a second location; and

means for providing a stable frequency reference and for using said frequency reference to characterize the timing and frequency stability of the EOI transmissions.

4. A system as recited in claim 3, further comprising a computer configured to compute the location of the EOI using data representative of the EOI transmissions stored during said first and second periods of time.