Performance evaluation of standard positioning service GPS receiver with LS and LQ estimators over southern region of Indian sub continent

With the discontinuity of Selective Availability (SA) by U.S government, obtaining accuracies upto tens of meters by GPS system became simpler. Though the performance level reached to millimeter level accuracy, it is only restricted to military domains and is provided under Precise Positioning Service (PPS) standards. The two different GPS services include PPS and Standard Positioning Service (SPS). All the Civil applications of GPS fall under this SPS Standard that can provide upto 40 meters of accuracy under ideal sky conditions. This paper mainly focuses in improving the SPS GPS receiver performance in terms of accuracy and precision by modeling the C/A (Coarse/Acquisition) measurements for Satellite Clock biases and Relativistic error. It also concentrates in implementing two different Position estimators, Least Squares (LS) and Linear Quadratic (LQ) Estimators and there by analyzing their performance in terms of Position Accuracy Measures. The data collected on LI (1575.42MHz) frequency of the SPS Dual Frequency GPS (DFGPS) receiver located at IISC, Bangalore (Lat/Lon: 13.01o N / 77.56o E) and Andhra University (AU), Visakhapatnam (Lat/Lon: 17.72oN / 83.32oE) are used for performance evaluation.