Abstract: A system embodiment of the present invention comprises a fixed and a roving pair of four-observable GPS receivers and a communication link between them for double differencing code and carrier measurements. Carrier phase integer ambiguities are resolved efficiently by searching the simultaneous narrow-lane intersections of both the L1 and L2 wave fronts propagated by the GPS satellites being tracked. External constraint information, such as elevation, is additionally used to speed up integer ambiguity resolution. Data between the reference station and the rover is communicated in compressed form at a regular interval, e.g., once a second at each epoch, and demi-measurements of carrier phase are obtained more frequently, e.g., ten times a second, and used to propagate solutions between epochs.

Abstract: A surveyor range pole, for example, equipped with a GPS receiver and antenna mounted at the top end, a battery mounted at the bottom end to better balance the pole, a tilt sensor and a direction sensor. The tilt sensor and direction sensor provide information about the vector that lies between the top and the bottom points of the range pole. The GPS receiver computes the position of the top end of the range pole from GPS satellite signals received by the GPS at the top end, and then computes the position of the bottom end of the range pole with the vector information. A variable length, telescoping range pole includes a linear transducer for automatically measuring the overall length of the range pole and contributing that length information to the vector calculation.