METHOD AND APPARATUS FOR ADS-B VALIDATION, ACTIVE AND PASSIVE MULTILATERATION, AND ELLIPTICAL SURVEILLANCE

• US 20100149019A1
• Filed: 06/06/2009
• Published: 06/17/2010
• Est. Priority Date: 03/05/1999
• Status: Active Grant

• Current Assignee: ERA as (Omnipol as)
• Original Assignee: Omnipol as
• Inventors: Smith, Alexander E., Breen, Thomas J., Evers, Carl A., Hulstrom, Russell
• Granted Patent: US 8,072,382 B2
• Time in Patent Office: Days
• US Class Current: 342/30
• CPC Class Codes: G01S 11/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 13/78 discriminating between different kinds of targets, e.g. IFF-radar, i.e. identification of friend or foe G01S13/75, G01S13/79 take precedence
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 13/91 for traffic control G01S13/93 takes precedence
• CPC Class Codes: G01S 13/93 for anti-collision purposes
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile

Abstract

A system and method are disclosed to track aircraft or other vehicles using techniques including multilateration and elliptical surveillance. Unlike conventional approaches that use time difference of arrival for multilateration at a fixed set of reception points, this technique allows targets to be tracked from a number of dynamic or moving reception points. This allows for triangulation/multilateration and elliptical surveillance of targets from combinations of fixed, fixed and moving or only moving ground-based receivers, sea-based receivers, airborne receivers and space-based receivers. Additionally this technique allows for ADS-B validation through data derived from only two receivers to assess the validity and integrity of the aircraft self-reported position by comparing the time of arrival of the emitted message at the second receiver to the predicted time of message arrival at the second receiver based on the self-reported position of the aircraft and the time of arrival at the first receiver. The benefits of using less than three receivers for validation include greater validation coverage areas using a smaller set of ground stations at a lower infrastructure cost.

Claims

1. A method of tracking vehicles, comprising the step of:

receiving, from at least one moving sensor, a radio signal,

time-stamping the radio signal from the at least one moving sensor at least one known location, to determine a time of arrival of the radio signal from the at least one moving sensor at the at least one known location,

calculating, from the time of arrival of the radio signal from at least one the moving sensor, a position of the at least one moving sensor,

receiving at the at least one moving sensor, a radio signal from a vehicle,

time-stamping the radio signal from the vehicle at the at least one moving sensor, to determine a time of arrival of the radio signal from the vehicle at the at least one moving sensor, and

calculating, from the time of arrival of the radio signal from the vehicle at the at least one the moving sensor, a position of the vehicle.

2. The method of claim 1, wherein at least one of the at least one moving sensors comprises an orbiting satellite.

3. The method of claim 1, wherein at least one of the at least one moving sensors comprises a ground vehicle moving sensor.

4. The method of claim 1, wherein at least one of the at least one moving sensors comprises a moving ship/vessel sensor.

5. The method of claim 2, wherein the orbiting satellite broadcasts calculated vehicle position.

6. A method of determining target position, comprising:

generating an interrogation signal from at least one interrogator,

receiving the interrogation signal at a plurality of receivers,

determining position of at least one interrogator from the interrogation signals received at the receivers,

receiving responses from an interrogation target at the receivers,

determining position of the interrogation target from the position of the at least one interrogator and the responses from the interrogation target at the receivers.

7. The method of claim 6, wherein the interrogator, target, and receivers comprise one or more of moving, fixed, and are based on one or more of land, sea, air, or space.

8. The method of claim 7, wherein the interrogator comprises an interrogator located on an aircraft.

9. The method of claim 6, further comprising the steps of:

time synchronizing the interrogator and the receivers to a common precision time reference,

calculating a target'"'"'s ellipse of position with respect to each receiver using the interrogator time of interrogation measurement and each receiver'"'"'s time of arrival measurement for the corresponding reply transmission, and

fusing elliptical line of positions for each receiver to generate a computed target position.

10. The system of claim 9, further comprising the steps of:

receiving a self-reported position from the target, and

comparing the self-reported position from the target with computed target position to determine accuracy of the self-reported position from the target.