A method for providing integrity information for checking atmospheric correction parameters for the correction of atmospheric disturbances for satellite navigation for a vehicle includes reading state signals relating to a state of an atmosphere between at least one satellite receiver and at least one satellite of the at least one satellite receiver. Each state signal represents certain state data that are transmitted between a satellite and a satellite receiver. The method further includes using at least one satellite signal and that are dependent on a state of the atmosphere between the satellite and the satellite receiver. The method further includes determining the integrity information using the state data. A variation of the state data against time is analyzed.

Determination of one or more timing (phase) and/or frequency corrections to be made to a local time base of a receiver device to synchronize the local time base with the time of GPS or other highly accurate time base. Timing packets from one or more grandmaster devices whose time bases are substantially the same as that of GPS or the like and/or positioning system signals (e.g., GPS signals) directly from a positioning system are received and manipulated to determine the timing and/or frequency corrections. The corrected time base may be used to assist in acquiring such positioning signals to allow for higher accuracy correction and/or for downstream communication operation. The present utilities are advantageous such as when a sufficient number of channels (e.g., four) from the receiver device to positioning system satellites are unavailable to synchronize the local time base to the GPS or other accurate time base.

In some implementations, a processor may retrieve predicted positioning data and predicted orbital data from global navigation satellite service (GNSS) positioning circuitry of a wireless device in response to a request for device time. The processor may retrieve long-term learning (LTL) data for a temperature sensing crystal (TSX) of the wireless device, the LTL data including S-curve characteristics of the TSX, and the time tracking uncertainty of the TSX. The processor may generate a GNSS-based device time estimate using the predicted positioning data and the predicted orbital data. The processor may perform TSX-based device time processing by updating the GNSS-based device time estimate using a clock signal of the TSX to generate a final device time estimate, the updating based on the retrieved LTL data for the TSX.

A method of receiving two chip-by-chip multiplexed CSK signals (e.g., GNSS signals) and searching for a non-CSK signal with optimal performance at a given digit capacity of a sampling memory resided in parallel correlators. For CSK signals Prompt, Early and Late results for each of possible code shift are calculated as different sums of four punctured convolutions. Depending on configuration, the method allows to receive both multiplexed CSK signals with lesser quality or one of the CSK signals with better quality. The method can be implemented as an apparatus with four punctured correlators, a set of multipliers by 1 or 2.sup.N, another set of multipliers by 1 or 0, summers of four input to one result, a RAM, searchers of maximum, and conditional commutators.

A method for accurately and efficiently calculating a dense ephemeris of a high-eccentricity orbit is provided. With respect to the ephemeris calculation of the high-eccentricity orbit, the method constructs uneven interpolation nodes through time transformation and interpolates by an interpolation polynomial based on uneven interpolation nodes to obtain a dense ephemeris, which significantly improves the calculation efficiency and accuracy. Based on a large-scale numerical experiment, the method derives an optimal universal value (that is, 0.3) of a transformation parameter for all orbital eccentricities and various interpolation polynomials. In the case of using the optimal universal value of the transformation parameter δ, the method further verifies the Hermite interpolation polynomial as the preferable one among various interpolation polynomials.

A method for accurately and efficiently calculating a dense ephemeris of a high-eccentricity orbit is provided. With respect to the ephemeris calculation of the high-eccentricity orbit, the method constructs uneven interpolation nodes through time transformation and interpolates by an interpolation polynomial based on uneven interpolation nodes to obtain a dense ephemeris, which significantly improves the calculation efficiency and accuracy. Based on a large-scale numerical experiment, the method derives an optimal universal value (that is, 0.3) of a transformation parameter for all orbital eccentricities and various interpolation polynomials. In the case of using the optimal universal value of the transformation parameter δ, the method further verifies the Hermite interpolation polynomial as the preferable one among various interpolation polynomials.

The present disclosure provides example satellite communication method, terminal device, and computer-readable storage medium. One example method includes receiving a first system message sent by a first satellite, where the first system message indicates a mean anomaly of the first satellite at an ephemeris reference time. A topology of a satellite network to which the first satellite belongs is determined based on the first system message.

Techniques are provided for non-linear satellite state modeling. First global navigation satellite systems (GNSS) signal data is obtained from a set of GNSS satellites. First satellite state data is obtained. The first satellite state data includes orbit data for the set of GNSS satellites. A non-linear satellite state model that includes a plurality of model parameters is generated. The non-linear satellite state model is generated by adjusting the plurality of model parameters based on the first GNSS signal data and the first satellite state data. The non-linear satellite state model outputs satellite state data based on GNSS signal data. Second GNSS signal data is obtained from the set of GNSS satellites. A set of updated satellite state data is calculated using the non-linear satellite state model and the second GNSS signal data.

An electronic timepiece includes a radio wave receiver, a communication unit, a memory and a processor. The radio wave receiver receives radio waves from positioning satellites. The communication unit communicates with an external device. The memory stores a program and predicted positional information on the positioning satellites. Based on the program stored in the memory, the processor shifts the timepiece between a normal operation state and a power saving state in which operation of the timepiece is restricted, depending on a status of the timepiece. In response to an elapsed time from a valid period of the predicted positional information exceeding a predetermined reference time during the power saving state, the processor causes the communication unit to receive updated data of the predicted positional information and other information from the external device when shifting the timepiece from the power saving state to the normal operation state.

An electronic timepiece includes a radio wave receiver, a communication unit, a memory and a processor. The radio wave receiver receives radio waves from positioning satellites. The communication unit communicates with an external device. The memory stores a program and predicted positional information on the positioning satellites. Based on the program stored in the memory, the processor shifts the timepiece between a normal operation state and a power saving state in which operation of the timepiece is restricted, depending on a status of the timepiece. In response to an elapsed time from a valid period of the predicted positional information exceeding a predetermined reference time during the power saving state, the processor causes the communication unit to receive updated data of the predicted positional information and other information from the external device when shifting the timepiece from the power saving state to the normal operation state.