Method, systems, and computer-readable media containing instructions which, when executed by a computing device, cause it to receive data from an inertial measurement unit, including GPS data, velocity data, and bearing data, receive data from a digital magnetic compass, including bearing data, receive data from a Doppler sensor, including velocity data and distance data, determining whether GPS location data is in consensus with a previous derived multi-source reckoning system location, determining a consensus distance value from a weighted average of data from the inertial measurement unit and the Doppler sensor, determine a consensus heading value from a weighted average of data from the inertial measurement unit and the digital magnetic compass, determine a consensus geolocation value from a weighted average of data from the inertial measurement unit and the previous derived multi-source reckoning system location, and determine a derived multi-source reckoning system location.

A ranging code correlation function detection system for use in a global navigation satellite system (GNSS) receiver includes a correlation block to correlate a digitized GNSS signal (e.g. at or above a critical sampling rate) with a corresponding ranging code at each of a plurality of different offsets from a current estimate of a code delay to generate a plurality of correlation data points; an interpolation filter configured to generate at least one estimated correlation data point that lies between two of the correlation data points based on the current estimate of the code delay. In some cases the ranging code correlation function detection system may also include a discriminator block configured to generate an updated estimate of the code delay based on the at least one estimated correlation data point.

Method, systems, and computer-readable media containing instructions which, when executed by a computing device, cause it to receive data from an inertial measurement unit, including GPS data, velocity data, and bearing data, receive data from a digital magnetic compass, including bearing data, receive data from a Doppler sensor, including velocity data and distance data, determining whether GPS location data is in consensus with a previous derived multi-source reckoning system location, determining a consensus distance value from a weighted average of data from the inertial measurement unit and the Doppler sensor, determine a consensus heading value from a weighted average of data from the inertial measurement unit and the digital magnetic compass, determine a consensus geolocation value from a weighted average of data from the inertial measurement unit and the previous derived multi-source reckoning system location, and determine a derived multi-source reckoning system location.

An error model calibration method can analyze discrete distribution situations of a pseudo-range measurement error and a Doppler measurement error under different carrier-to-noise ratios and altitude helping to calibrate and improve the universality of error model calibration. Observation data is received and satellite data is acquired based on the observation data. A pseudo-range error array and a Doppler error array are calibrated based on the observation data, geometric parameters, and the satellite data. The pseudo range error array describes errors of two terminals under a carrier-to-noise ratio and altitude angle of a satellite. The Doppler error array describes a discrete distribution of the two terminals. The pseudo-range error models respectively corresponding to the at least two terminals are fit using the pseudo-range error array. The Doppler error models respectively corresponding to the at least two terminals are fit using the Doppler error array.

A location detection system performs a process that uses data from a satellite navigation sensor in conjunction with data from a second sensor to determine the accuracy of location estimates provided by the satellite navigation sensor. The system uses the satellite navigation sensor to determine location estimates from at a first time and a second time. The system also uses data from the second sensor to determine a third location estimate, which represents another estimate of the system's location at the second time. The system uses the three location estimates to determine whether the second location estimate satisfies an accuracy condition. If the accuracy condition is satisfied, then the second location estimate may be provided as input to a process.

A satellite system operates at altitudes between 100 and 350 km relying on vehicles including a self-sustaining ion engine to counteract atmospheric drag to maintain near-constant orbit dynamics. The system operates at altitudes that are substantially lower than traditional satellites, reducing size, weight and cost of the vehicles and their constituent subsystems such as optical imagers, radars, and radio links. The system can include a large number of lower cost, mass, and altitude vehicles, enabling revisit times substantially shorter than previous satellite systems. The vehicles spend their orbit at low altitude, high atmospheric density conditions that have heretofore been virtually impossible to consider for stable orbits. Short revisit times at low altitudes enable near-real time imaging at high resolution and low cost. At such altitudes, the system has no impact on space junk issues of traditional LEO orbits, and is self-cleaning in that space junk or disabled craft will de-orbit.

Disclosed are a positioning system and a positioning method using a low earth orbit satellite. The positioning system using a low earth orbit satellite according to the present invention comprises a generation unit for generating, when a communication period with a ground control station is reached, a first telemetry signal including a time value according to a reference time used by a low earth orbit satellite; a confirmation unit for confirming, on the basis of a navigation signal received from a navigation satellite, the GNSS time used as a reference by the navigation satellite; an adjustment unit for adjusting the time value in the first telemetry signal so as to be synchronized with the GNSS time; and a transmission unit for broadcast transmitting a second telemetry signal, after the adjustment, so that a positioning receiver on the ground can determine the position by using the second telemetry signal.

Methods, apparatuses and/or articles of manufacture, which may be employed in a mobile device and/or in a location server, enable acquisition assistance at the mobile device. In at least one implementation, which is not intended to limit claimed subject matter, acquisition assistance may include expected Doppler frequency shift and expected code phase in the case of a particular Global Navigation Satellite System (GNSS) satellite vehicle, as well as a search window for each of these, and a confidence value. The confidence value may indicate the likelihood of detecting signals from the satellite vehicle at the current expected location of the mobile device and within the given search windows and may enable one or more of faster location estimation, reduced battery consumption, and detection of weaker satellite signals.

Methods and devices are presented for synchronizing positioning signals in a kinematic location network. In particular, methods and devices are presented for synchronizing a unique positioning signal generated by a positioning-unit device to a reference positioning signal generated by a reference transmitter, where the positioning-unit device and the reference transmitter are moving relative to each other. In certain embodiments the reference transmitter or the positioning-unit device, or both, self-monitor trajectory data comprising one or more of location, velocity or acceleration, e.g. using inertial navigation systems, and broadcast that data in their positioning signals. The trajectory data enables estimation of Doppler shifts and propagation delays associated with the positioning signals, allowing measurement and correction of clock drift for synchronization of the positioning signals.

A satellite system operates at altitudes between 100 and 350 km relying on vehicles including a self-sustaining ion engine to counteract atmospheric drag to maintain near-constant orbit dynamics. The system operates at altitudes that are substantially lower than traditional satellites, reducing size, weight and cost of the vehicles and their constituent subsystems such as optical imagers, radars, and radio links. The system can include a large number of lower cost, mass, and altitude vehicles, enabling revisit times substantially shorter than previous satellite systems. The vehicles spend their orbit at low altitude, high atmospheric density conditions that have heretofore been virtually impossible to consider for stable orbits. Short revisit times at low altitudes enable near-real time imaging at high resolution and low cost. At such altitudes, the system has no impact on space junk issues of traditional LEO orbits, and is self-cleaning in that space junk or disabled craft will de-orbit.