SYSTEM AND PROCESS OF DETERMINING VEHICLE ATTITUDE

• US 20140266882A1
• Filed: 03/12/2014
• Published: 09/18/2014
• Est. Priority Date: 03/12/2013
• Status: Active Grant

• Current Assignee: Australian Rail Track Corp. Ltd. (Government of Australia)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: METZGER, Thomas R.
• Granted Patent: US 10,012,736 B2
• Time in Patent Office: Days
• US Class Current: 342/357.59
• CPC Class Codes: G01S 19/21 Interference related issues ; Issues related to cross-correlation, spoofing or other methods of denial of service
• CPC Class Codes: G01S 19/215 issues related to spoofing
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: G01S 19/53 Determining attitude
• CPC Class Codes: G01S 3/28 using amplitude comparison of signals derived simultaneously from receiving antennas or antenna systems having differently-oriented directivity characteristics

Abstract

A system and process that can be used to determine vehicle attitude with only one navigation receiver. In one embodiment, the antenna of the navigation receiver is driven with a signal that modulates sensitivity in azimuth. The received navigation signal strength is demodulated by the phase at which the antenna is sweeping and a phase angle and a magnitude for the incoming signal are calculated. Using this calculated phase angle, magnitude and antenna characteristics, the location of the user (i.e. the navigation receiver) and the location of the navigation satellite, the attitude of the antenna and hence the user or user vehicle can be determined.

Claims

1. A process of determining vehicle attitude using one or more navigation satellites, comprising:

modulating the sensitivity of an antenna of a single navigation receiver in azimuth;

using the navigation receiver to receive a navigation signal from at least one navigation satellite;

demodulating the received navigation signal strength by the phase at which the antenna is sweeping and determining a phase angle for the incoming signal;

determining the location of the navigation receiver;

determining the location of the one navigation satellite; and

using the phase angle, the location of the navigation receiver and the location of the one navigation satellite to determine the attitude of the vehicle.

2. The process of claim 1, further comprising:

using the navigation receiver to receive multiple navigation signals from multiple navigation satellites;

determining a phase angle for each of the incoming signals;

determining the location of each navigation satellite; and

using the phase angles, the location of the navigation receiver and the locations of the navigation satellites to determine the attitude of the vehicle.

3. The process of claim 1, further comprising determining if the received navigation signals are coming from the wrong angle or if the received navigation signals are all coming from the same angle, wherein the navigation receiver has an anti-spoofing capability.

4. The process of claim 1, further comprising an array of the antennas on the vehicle, each antenna having a single navigation receiver, and each antenna is pointed in a different direction;

using each navigation receiver to receive a navigation signal from at least one navigation satellite;

determining an angle for the incoming signal to each antenna using the received navigation signal strength and based on the direction at which the respective antenna is pointing; and

determining the attitude of the vehicle using the angles, the location of the vehicle and the location of the at least one navigation satellite.

5. The process of claim 4, further comprising rejecting jamming signals coming from a signal source that is in a direct line with one of the antennas, and using other antennas of the array to receive navigation signals, wherein that the array of antennas has an anti jamming capability.