Achievable accuracy of an azimuth obtained at short range with use of GPS and geodetic instruments

The problem of finding optimal estimates of the azimuth using the GPS coordinates is considered. The azimuth accuracy is improved through using additional measurement data of distances between reference points. It is also possible to use the measurement data of the angles between the directions to the reference points. An original algorithm for obtaining optimal estimates of azimuths is suggested. The algorithm enables to find a priori a root mean square error of the azimuth. The accuracy of the GPS coordinates, measuring distances and angles is supposed to be known. Using the algorithm, calculating azimuth accuracy was performed and the analysis of two approaches to the reference points’ location carried out. The first approach supposes the minimum number of reference points with a given precision of the azimuth. The second one is characterized by the minimum sizes of the polygon, which are the reference points. Both approaches were considered from the point of view of achieving high accuracy of finding the azimuth. As a result the possibility of finding the azimuth with root mean square error of about 1? is confirmed, when the distance between reference points is less than 400 m.