Differential Global Positioning SystemDGPS Surveyors in india The position could be more accurate if it not for that the signal from the satellite is affected by the ionosphere and troposphere, as well as errors in the satellite clocks and satellite ephemeris. You can install a DGPS receiver to obtain even better precision. The positional accuracy is then 1-2 metres in practice, but only 8 metres is indicated for legal reasons.
DGPS Surveyor In cooperation with our neighbouring countries and in line with the recommendations of the IALA, the Swedish Maritime Administration has established a reference station network for GPS. The reference station calculates the distance error to every satellite and transmits a correction via LF, along with information about the reliability of the station, the quality of the correction, and notice of whether any particular satellite should not be used. Corrections can be sent for a maximum of 12 satellites whose elevation angles exceed 7 degrees. The transmitted signal is monitored by a control receiver. If the calculated position deviates more than 8 metres from the measured position of the station, it sends an error message to your DGPS receiver. Positional accuracy can be as good as around one metre if you have a good DGPS receiver. Resistance to interference increases if the correction receiver’s antenna is of the H-field type (loop) and if the receiver has special built-in technology for removing impulse interference.