| This research is mainly focused on a new algorithm proposed to address the on-the-fly ambiguity resolution problem in real-time differential GPS positioning. The new algorithm consists of an “intermediate ambiguity search strategy (IASS)” and an “estimator bank” with a search window as a bridge between both components (i.e. IASS and the estimator bank). Based on the proposed (new) algorithm, the program, “Real Time Positioning (RTP)”, was developed using MATLAB. As compared with existing methods, the advantages of the proposed algorithm include simplicity, robustness, and versatility.; Three GPS experiments (i.e. one static and two kinematic cases—buoy and aircraft) were used to evaluate the capability of the proposed algorithm. And, to confirm the validation of the proposed algorithm, results from MSODP (Multi Satellite Orbit Determination Program), a tide gauge, and KARS (Kinematic And Rapid Static) code were adopted as the reference values. The test results of these three cases indicate that the magnitudes of average differences (between the RTP solution and the reference values) are less than 1.9 cm and the corresponding standard deviations are less than 1.3 cm in the three components (X,Y,Z) of the ECEF (Earth-Centered Earth-Fixed) coordinate system and in the vertical direction of the local geodetic coordinate system. In addition, the average processing time (from the input of the RINEX and navigation files to position estimates) is less than or equal to 0.627 seconds for each epoch during the confirmation period as the data were collected at a rate of 1 Hz, which allows the proposed algorithm to meet a requirement for high accuracy, real-time positioning. |
