This assumes the calculation of corrections based on the observations from the nearest reference stations around the user. It is recommended that you use them if you are at large distances from any reference station or if the nearest reference station is out of order. ROMPOS offers access to 4 types of network products: MAX, iMAX, FKP and VRS. An example of a network product is RO_MAX_ 3.1 _GG, which means that a MAC product is to be used in RTCM 3.1 format, with data from GPS and GLONASS satellite constellations.