Patronics International Limited,
Email: [email protected]
With the advent of RTK GPS in surveying activities, GPS has offered an efficient means of providing instantaneous positions whereby users can obtain sub-centimetre/millimetre level positioning in real time. In RTK GPS all algorithms using code information only are limited to range accuracy of about 0.5-1.0 metres due to code noise. However, range measurement using carrier phase information on the other hand is limited to only 0.5-3.0 millimetres by noise. Thus the use of carrier phase measurements in high precision positioning has become indispensable. Yet in order to use the carrier phase measurements, the user has a couple of positioning errors to deal with. This research work uses an exponentially weighted Extended Kalman Filter (EWEKF) with the integration of detection, identification, adaptation (DIA) method as an attempt to remove/isolate the effects of errors on GPS signals during transmission.