An enhanced L-band Digital Aeronautical Communications System (LDACS) includes a plurality of LDACS ground stations, each transmitting a respective carrier signal. An LDACS airborne station may be configured to communicate with the plurality of LDACS ground stations and determine position information based upon respective Doppler shifts in the plurality of carrier signals.

The present invention belongs to the field of satellite navigation and positioning technology, more specifically a GNSS standard point positioning method based on the spherical harmonics. The method achieves the calculation of the station position with GNSS observations and satellite broadcast ephemeris. In this method, spherical harmonics are used to describe the errors related to the elevation and azimuth angle between the station and the satellite, including tropospheric delay errors and ionospheric delay errors. Compared with the existing methods of correcting the tropospheric delay by using empirical models, the method in the present invention can obtain the position information of survey points quickly and with high efficiency and present advantages such as a simple practical performance, a convenient data process and high calculation efficiency.

An Real-Time Kinematic (RTK) and/or Differential GNSS (DGNSS) system is disclosed in which correction data from a plurality of reference stations is provided to the mobile device. A selection of reference stations (from which correction data is provided to the mobile device) can be made based on factors such as the approximate location of the mobile device, geometry of the reference stations, and/or other factors. The mobile device can combine the correction data from the plurality of reference stations in different ways to determine an accurate position fix for the mobile device, without interpolating correction data from the plurality of reference stations.

A system and method for determining a receiver position can include determining a receiver position based on a set of satellite observations, determining the receiver position based on sensor measurements, determining a satellite observation discontinuity; based on the satellite observation discontinuity, determining a second receiver position.

A virtual reference station switching method includes obtaining networking change information of a reference station network, obtaining prediction information based on the networking change information of the reference station network, where the prediction information includes a reference station combination used to calculate a virtual reference station of a mobile station is switched from a first reference station combination to a second reference station combination, obtaining a first virtual reference station through calculation based on the first reference station combination, and obtaining a second virtual reference station through calculation based on the second reference station combination, and providing at least one of first virtual reference station information or second virtual reference station information to the mobile station.

According to the present application, when an inter frequency bias (IFB) calibration value, which corresponds to a machine type ID of a reference station, is not stored in a storage, a processor executes a Real Time Kinematic (RTK) calculation by using reference station-positioning data and positioning terminal-positioning data, calculates a positioning solution, and causes the storage to store the reference station-positioning data and the positioning terminal-positioning data. The processor executes, after completing a positioning processing, an estimation processing of the IFB calibration value by using the reference station-positioning data and the positioning terminal-positioning data which are stored in the storage.

A grid interval to be used in transmitting positioning augmentation information from a quasi-zenith satellite is set on the basis of statistical information of index values of occurrence degree of ionospheric disturbance for each area of the ground divided into a plurality of areas.

A system and method for determining a receiver position can include determining a receiver position based on a set of satellite observations, determining the receiver position based on sensor measurements, determining a satellite observation discontinuity; based on the satellite observation discontinuity, determining a second receiver position.

A system and method for generating a set of GNSS corrections using a GNSS corrections model comprising a Gaussian process.

A system or method for generating or distributing GNSS corrections can include or operate to: generate a set of corrections based on satellite observations, wherein each correction of the set of corrections comprises an area associated with the correction, a tag, and correction data; update a set of stored corrections with the set of received corrections based on a tag associated with each correction of the set of stored corrections and the tag associated with each correction of the set of received corrections; and transmit stored corrections of the set of stored corrections to the GNSS receiver when the area associated with the stored corrections matches the locality of the GNSS receiver.