DETECTION AND CORRECTION OF CARRIER PHASE INCONSISTENCY DURING THE TRACKING OF A RADIO NAVIGATION SIGNAL

• US 20140062771A1
• Filed: 03/16/2012
• Published: 03/06/2014
• Est. Priority Date: 03/16/2011
• Status: Active Grant

• Current Assignee: Safran Electronics & Defense
• Original Assignee: Safran Electronics & Defense
• Inventors: Lebrat, Jean-Philippe
• Granted Patent: US 9,285,480 B2
• Time in Patent Office: Days
• US Class Current: 342/357.26
• CPC Class Codes: A63H 3/04 with deformable framework
• CPC Class Codes: A63H 3/46 Connections for limbs
• CPC Class Codes: C10L 5/36 Shape
• CPC Class Codes: C10L 5/40 essentially based on materials of non-mineral origin
• CPC Class Codes: C10L 5/44 on vegetable substances
• CPC Class Codes: G01S 19/20 Integrity monitoring, fault detection or fault isolation of space segment
• CPC Class Codes: G01S 19/26 involving a sensor measurement for aiding acquisition or tracking
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/43 using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel
• CPC Class Codes: Y02T 50/678 Aviation using fuels of non-fossil origin

Abstract

The invention relates to a method for tracking the carrier phase of a signal received from a satellite by a carrier using a carrier loop of the carrier phase, said signal being acquired by a navigation system of the carrier, said navigation system including a receiver for location by radio navigation, and a self-contained unit, wherein the receiver is suitable for acquiring and tracking the phase of the carrier of the signal from the satellite.

Claims

1. A method for tracking the carrier phase of a signal received from a satellite by a carrier by means of a carrier phase tracking loop, said signal being acquired by a navigation system of the carrier which comprises a localization receiver (10) by radio navigation and a self-contained unit (20), the receiver (10) being adapted for acquiring and tracking the phase of the carrier of the signal from the satellite, the method comprising the following steps:

determining (E1) a closed-loop control error of the carrier phase loop, said closed-loop control error being determined between two sampling instants and corresponding to a first phase deviation;

determining (E2) an acceleration variation of the carrier between the two sampling instants by means of the self-contained unit (20);

projecting (E3) the acceleration variation on a satellite-receiver view axis for obtaining a second phase deviation;

comparing (E4) the first and second deviations in order to detect an error on the measurement of the carrier phase tracked by said carrier phase loop, said comparison consisting of determining inconsistency of the first deviation with the second deviation.

2. The method according to claim 1, wherein the acceleration variation of the carrier is obtained by means of a numerical model implemented in a module (21) of the navigation system.

3. The method according to claim 1, wherein the acceleration variation of the carrier is determined by means of an inertial unit (21) of the navigation system.

4. The method according to one of the preceding claims, wherein the inconsistency is Integrated over a sliding period with a duration of the order of one to five times a time constant of a filter of the carrier phase loop and then compared with the threshold, typically of λ

/4, the method comprises a step (E5) for generating a replica signal of the received signal from the phase deviation {δ

γ

_n.δ

t²}_projected stemming from the self-contained unit (20).

5. The method according to claim 4, comprising a step (E6) for determining a navigation solution from integrated dopplers stemming from the generated replica signal.

6. The method according to one of the preceding claims, wherein if the inconsistency is greater than the threshold, typically of the order of λ

/4, the method comprises a step (E5′

) for correcting the integrated dopplers required for the navigation solution, the correction consisting of adding a term k.λ

/2 to said integrated dopplers wherein k is a relative integer such that the absolute value of the integrated inconsistency is less than the threshold, the threshold being typically of the order of λ

/4.

7. The method according to claim 6, comprising a step (E6) for determining a navigation solution from the corrected integrated dopplers.

8. The method according to one of the preceding claims, wherein the comparison consists of calculating an inconsistency term defined in the following way;

9. A navigation system comprising a satellite position receiver comprising means for applying a method according to one of the preceding claims.