A system of architecture, apparatus and calibration method is invented for high-power flexible-polarization payload for satellite communications. The system comprises onboard phase-tracked apparatus, flexible polarization mechanism, and in-orbit calibration method. The power combining and polarization performance of the phase-tracked payload is monitored on ground by measuring the cross-polarization discrimination (XPD) and/or axial ratio (AR). The high performance over the life is achieved by optimization of the XPD or AR on ground and adjusting complex gain of the transponders. The high-power flexible-polarization in-orbit-calibration payload may be applied but not limited to UHF, L, S, C, X, Ku and Ka-band high power satellite systems.

A disciplined clock provides a disciplined time and a disciplined frequency synchronous with a reference clock. The disciplined clock includes: a time receiver to: receive a common view signal from the common view clock; and produce a receiver timing signal; a local clock to: receive a frequency correction; and produce a local timing signal; a time interval counter to: receive the receiver timing signal from the time receiver; receive the local timing signal from the lock clock; and determine a time difference between the receiver timing signal and the local timing signal; and a controller to: receive the time difference from the time interval counter; and communicate the frequency correction, based on the time difference, to the local clock.

The approach presented here relates to a method for detecting a group runtime variation for a navigation sensor for a navigation system for a vehicle. The method comprises a step of reading and a step of determining. In the reading step, at least one first GNSS simulator signal is read from a virtual satellite of a virtual global navigation satellite system at a first time and a second GNSS simulator signal is read from the virtual satellite or from at least one second virtual satellite of the virtual navigation satellite system at a second time different to the first time by means of a read device. The group runtime variation is determined using the first GNSS simulator signal and the second GNSS simulator signal in the determining step.

A method for maintaining timing accuracy in a mobile device includes: obtaining a range estimate using a signal received from a timing information source via a communication unit of the mobile device; obtaining position and velocity estimate information for the mobile device from a source of position and velocity information separate from the timing information source, the position and velocity estimate information being obtained from at least one sensor of the mobile device, or via a communication unit of the mobile device using a Vehicle-to-Everything wireless communication protocol, or a combination thereof; determining estimated clock parameters based on the position and velocity estimate information and the range estimate; and adjusting a clock of the mobile device based on the estimated clock parameters in response to a position-and-velocity-assisted timing uncertainty corresponding to the estimated clock parameters being below a timing uncertainty threshold.

A rear axle center (RAC) locating system may include a tractor and a RAC location acquisition unit. The tractor may include a rear axle having a center, a global positioning system (GPS) antenna offset from the rear axle, and inertial measurement units. The RAC location acquisition unit may include a processing unit and a non-transitory computer-readable medium containing instructions to direct the processing unit to determine a geographic location of the GPS antenna based upon signals received by the GPS antenna and determine a geographic location of the center of the rear axle based upon the geographic location of the GPS antenna and combined data from the inertial measurement units.

A method, device, computer equipment and storage medium for GNSS time synchronization are disclosed. The method includes: receiving data packet of NMEA protocol, reading a valid UTC time from data packet of NMEA protocol, and storing the read valid UTC time in a time synchronization controller; receiving PPS signal, capturing a local time output by local clock when PPS signal is generated, and storing the local time in the time synchronization controller; reading a last local time stored before the current local time and reading the stored latest UTC time as a UTC time corresponding to the last local time when the time synchronization controller receives the current local time; and determining, by the time synchronization controller, a local time correction amount according to the last local time and the UTC time corresponding to the last local time, and correcting the local clock according to the local time correction amount.

Disclosed are a device, computer program and method, for determining a range to a target, the device comprising a global positioning system (GPS) receiver, a pressure sensor, a temperature sensor, a controller; wherein the method comprises determining the device's geographic location based on coordinates from the GPS receiver and the device's elevation based on pressure and temperature data from the sensors; obtaining a location and elevation of a landmark based on GPS coordinates from a database; determining a distance between the device and the landmark using GPS coordinates; applying a slope compensation based on the difference in elevation between the device's elevation and the landmark; and converting the distance to a signal perceptible to a user.

Techniques described herein address these and other issues by utilizing two or more sensors to take temperature measurements from which a temperature-differential or instantaneous temperature rate-of-change, can be determined. In turn, this can be used to make a highly accurate model of the relationship between the temperature, temperature-differential, and clock circuitry frequency, to accurately estimate the frequency rate-of-change for frequency correction/compensation.

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 test device determines a Global Navigation Satellite System (GNSS) signal propagation delay in a GNSS signal distribution system (GSDS) for a radio access network. The test device includes a GNSS receiver and a clock. The GNSS receiver is connected at different times to a reference GSDS with a known signal propagation delay and to a device under test (DUT), including a second GSDS having an unknown signal propagation delay. One pulse per second (1PPS) signals are generated by the GNSS receiver and are compared to determine the unknown signal propagation delay of the DUT.