A satellite radiowave receiving device includes a receiver and a processor. The receiver acquires and receives radiowaves from a positioning satellite. The processor performing a positioning operation based on the radiowaves received by the receiver to obtain a current position of the satellite radiowave receiving device. The processor causes the receiver to stop an acquiring operation of radiowaves from a new positioning satellite under a predetermined condition while radiowaves are being acquired from a required number of positioning satellite for the positioning operation. If an error range of the obtained current position no longer satisfies a predetermined accuracy standard during a stop of the acquiring operation, the processor causes the receiver to resume the acquiring operation.

Certain implementations of the disclosed technology may include systems and methods for reducing noise in dual-frequency GNSS signal observation. The method can include: receiving, at a GNSS receiver, a first signal and a second signal. At least the second signal includes noise. The first signal is characterized by a first carrier frequency, and the second signal is characterized by a second carrier frequency. The method includes: down converting, sampling, cross-correlating, accumulating, determining ambiguous instantaneous phases, determining non-ambiguous instantaneous phases, producing normalized non-ambiguous instantaneous first phase samples, constructing a normalized first counter rotation phasor, generating a counter-rotated second observable, applying a low pass filter to remove noise; and outputting the filtered second observable.

An aircraft and non-transitory computer-readable medium for detecting the spoofing of a signal from a satellite in orbit. A receiver on the aircraft to receive an apparent satellite signal. A computer for determining at least two characteristic signatures of the signal including a power level, and indicating the apparent satellite signal is a spoofed satellite signal.

The present invention relates to a method for acquiring satellite signals. The method utilizes the predictability of the first two words of each sub-frame of the navigation message, by controlling the acquisition time of the intermediate frequency data and the PN code, acquiring corresponding intermediate frequency data and PN code from the acquisition time, processing the intermediate frequency data and the PN code to determine whether the satellite signal is acquired, during the acquisition processing and determination process, the navigation message peeling operation is performed using the predictability of the first two words of each sub-frame of the satellite navigation message and PN code, in this way, extending the time of coherent integration is achieved, and thereby improves the acquisition sensitivity.

Described herein is a method for improving the reception of a satellite navigation message divided in several pages and transmitted by one or several satellites. A satellite navigation message M of k pages is encoded in n pages, and any k retrieved pages from any satellite enables decoding of the original satellite navigation message M. An implementation of the method uses parallel block encoding for a binary erasure channel with high parity and zero overhead, where symbols at a fixed position of all pages are encoded in parallel into shorter codes. This method achieves full page interchangeability in the message transmission, optimizes message reception and reduces decoding cost.

A railway positioning method, based on the movement of a train determined by a signal receiver of a satellite navigation system embedded onboard the train, and on the movement of the train determined by an odometer embedded onboard the train, and a map of the railway tracks, by determination of the ionospheric propagation bias corresponding to a propagation bias of the signal carrier phase of the satellite navigation system, comprises the steps of, by line of sight of the satellites of the navigation system: estimating the biased ionospheric drift by difference between an integrated Doppler term determined by the receiver and a biased estimation of the movement of the train by the odometer; estimating the odometer drift bias and the drift bias of the local clock of the receiver, by least squares resolution of the speed determined by the satellite navigation system, of the drift bias of the local clock of the receiver, and of the odometer drift bias; correcting the estimation of the ionospheric drift, by subtraction of the estimated odometer drift bias; and correcting the integrated Doppler term using the drift bias of the local clock of the receiver and the ionospheric drift bias, and correcting the pseudo-distance deviations using the ionospheric drift bias.

A position detection method to be executed by a computer, the position detection method includes transmitting, by a sensor terminal, a signal obtained by performing capture processing on a satellite signal from a satellite of a search target according to an order of the satellites of the search targets; calculating, by a calculation device, a position of the sensor terminal based on a signal transmitted by the sensor terminal; and determining a satellite having a highest discovery probability based on a specific estimation method for second and subsequent search targets, using an index which is reflected larger as the discovery probability of other satellites is higher or lower, in a case where the first satellite is captured when a first search target is determined.

A method of processing a satellite signal includes: receiving a satellite positioning system (SPS) signal, including an SPS data signal of unknown data content, from a satellite at a wireless communication device; receiving symbol indications, of determined symbol values, from a terrestrial wireless communication system at the wireless communication device; correlating the SPS data signal with a pseudo-random noise code to obtain first correlation results; and using the symbol indications and the first correlation results to determine a measurement of the SPS signal.

A satellite-based positioning system (SPS) signal processing technique re-samples a received series of PRN sequences from an SPS satellite to align them with a nominal sampling rate for a corresponding series of perfect reference PRN replica sequences.

Systems, methods and apparatuses for generating long coherent integrations of received global navigation satellite system (GNSS) signals are described. One method includes generating coherent 1 second I/Q correlations by at least two stages of summation starting with 1 millisecond correlated I/Q signal samples. Intermediate stage coherent I/Q correlations may be modified based on, for example, lack of carrier phase lock and/or the carrier signal-to-noise density (C/N.sub.0). Such modifications include phase rotation. Energy/power amplitudes calculated from the coherent 1 second I/Q correlations may be used for improving multipath mitigation, the signal-to-noise ratio (SNR), and other GNSS receiver operations and functions.