A Matlab Implementation of Differential GPS for Low-cost GPS Receivers

A number of public codes exist for GPS (global positioning system) positioning and baseline determination in off-line mode. However, no software code exists for DGPS (differential GPS) exploiting correction factors at base stations, without relying on double difference information. In order to accomplish it, a methodology is introduced in MATLAB environment for DGPS using C/A (course acquisition) pseudoranges on single frequency L1 only to make it feasible for low-cost GPS receivers. The base station is at accurately surveyed reference point. Pseudoranges and geometric ranges are compared at base station to compute the correction factors. These correction factors are then handed over to rover for all valid satellites observed during an epoch. The rover takes it into account for its own true position determination for corresponding epoch. In order to validate the proposed algorithm, the rover is also placed at a pre-determined location. The proposed code is an appropriate and simple to use tool for post-processing of GPS raw data for accurate position determination of a rover e.g. Unmanned Aerial Vehicle during post-mission analysis.