A METHOD FOR DETERMINING THE HALF-CYCLE AMBIGUITY OF A GNSS CARRIER PHASE

• Main Authors: SLEEWAEGEN, Jean-Marie, SCHELLEKENS, Dries
• Format: Patent
• Language: English; French; German
• Published: 12.04.2023
• Subjects: ANALOGOUS ARRANGEMENTS USING OTHER WAVES; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES; MEASURING; PHYSICS; RADIO DIRECTION-FINDING; RADIO NAVIGATION; TESTING

According to the invention, the four signals L1CA, L1P, L2P and L2C transmitted by a GPS satellite are received and the carrier phases ϕLCA and φL2C are estimated from L1CA and L2C in the manner known in the art. In addition, the cross-correlation P between the downconverted signals L1P and L2P is determined, taking into account the delay between said signals. According to the invention, the sign of P is used in a novel way that enables the direct determination of the half-cycle ambiguity AL1CA of the L1CA signal. According to a first embodiment, this is done by downconverting the L2P signal by a replica having a phase derived from ϕL2C, instead of determining the phase of the L2P replica by a tracking loop as in the prior art. This new approach enables determining AL1CA directly from the sign of P. According to a second embodiment, the phase ϕL2P of the L2P replica is determined by a tracking loop as in the prior art, and the half-cycle ambiguity AL1CA is determined on the basis of the sign of P and on the basis of the difference between the carrier phases ϕL2P and ϕL2C. The invention is equally related to a GPS receiver comprising at least one channel configured for executing the method according to the first or second embodiment.