Abstract: A positioning system and method for resilient ephemeris decoding of Global Navigation Satellite System (GNSS) satellite information is provided. The positioning system decodes first ephemeris data of a satellite in a GNSS satellite constellation and estimates a first position of the satellite at a first time-instant. The positioning system further estimates a deviation between the estimated first position and a position where the satellite is expected to be at the first time-instant and determines the estimated deviation to be above a threshold. The positioning system excludes use of the estimated first position in a position fixing operation of the positioning system based on the determination. The positioning system decodes second ephemeris data of the satellite based on the exclusion, estimates a second position of the satellite at a second time-instant, and controls a position filter of the positioning system to use the estimated second position in the position fixing operation.

Abstract: A Global Navigation Satellite System (GNSS) and method for switching between Phase Locked Loop (PLL) and Automatic Frequency Control (AFC) tracking loops inside the GNSS receiver is provided. The GNSS receiver acquires a signal from a satellite of a GNSS satellite constellation and receives information associated with external conditions that impact a decoding performance, or a phase or frequency tracking performance, of the GNSS receiver. The GNSS receiver updates a value of a switching threshold based on the received information and compares a strength of the signal with the updated value. The GNSS receiver selects a tracking loop as one of AFC or PLL, based on the comparison. Thereafter, the GNSS receiver generates, by the selected tracking loop, measurements associated with parameters of a carrier component of the signal and decodes satellite data of the signal based on the measurements.

Abstract: A positioning system and method for resilient ephemeris decoding of Global Navigation Satellite System (GNSS) satellite information is provided. The positioning system decodes first ephemeris data of a satellite in a GNSS satellite constellation and estimates a first position of the satellite at a first time-instant. The positioning system further estimates a deviation between the estimated first position and a position where the satellite is expected to be at the first time-instant and determines the estimated deviation to be above a threshold. The positioning system excludes use of the estimated first position in a position fixing operation of the positioning system based on the determination. The positioning system decodes second ephemeris data of the satellite based on the exclusion, estimates a second position of the satellite at a second time-instant, and controls a position filter of the positioning system to use the estimated second position in the position fixing operation.

Abstract: A method of acquiring viscosity of a downhole fluid is provided. The downhole fluid is in a downhole tool positionable in a wellbore penetrating a subterranean formation. The method involves obtaining a viscosity signal of the downhole fluid using a vibrating wire viscometer of the downhole tool, and acquiring viscosity parameters of the viscosity signal. The acquiring involves adjusting the viscosity signal by removing offsets from the viscosity signal, generating a complex signal from the adjusted viscosity signal, obtaining a low frequency component of the complex signal by filtering the complex signal into a high frequency component and the low frequency component and removing the high frequency component, and determining the viscosity parameters from the low frequency component.