Въпрос
What real-time network solutions GeoNet offer?
GeoNet offer three main network solutions: VRS (Virtual Reference Station), MAX (Master Auxiliary Corrections), FKP (Flächen-Korrectur-Parameter) - area parameter correction.
VRS network solution - the system generates data for a "non-existing" virtual station, based on observations of actual reference stations. This allows elimination of systematic data errors accumulated with increasing the distance between the actual station and RTK position.
In order to generate VRS is necessary the rover to send its approximate coordinates (NMEA) to the system server. The system needs this data to generate a virtual station and corrections near the rover. For this VRS solution you can use data acquired from both GPS and GLONASS. It helps to reduce the time for initialization and increase the accuracy and reliability of measurements in poor conditions.
The basic concept for MAX network solution is related to the use of reference stations, in which phase distances are with equal levels of ambiguity. When phase distances are with equal levels of ambiguity, dispersive errors can be calculated for each frequency and each satellite-receiver pair. To obtain corrections through MAX, five real stations should be used. One of them is master, and the other 4 are supporting. The MAX solution does not require the rover to send data for its location. It's current disadvantage is that MAX solution uses only GPS system data and can not benefit of GNSS technology.
FKP area corrections are actually correction parameters of real reference stations. These corrections have coefficients reflecting horizontal gradients of ionospheric and geometric errors in the network. To calculate them coefficients the rover must send data to the system server for its approximate location.