Implemented GPS Software Receiver

A GPS software receiver is a complete signal processing system implemented entirely through software, capable of receiving and processing signals transmitted by GPS satellites to ultimately calculate the receiver's position, velocity, and time information. The GPS software receiver program implemented in the MATLAB environment provides a comprehensive solution from digital intermediate frequency (IF) signals to final positioning results.

The program covers all aspects of GPS signal processing, including signal acquisition, tracking, navigation data decoding, pseudorange measurement, and positioning calculation. The acquisition algorithm is responsible for detecting and initially estimating the arrival time and Doppler frequency shift of GPS satellite signals, while the tracking algorithm further precisely locks onto the signal and continuously demodulates navigation data. Key implementation functions include cross-correlation detection for signal acquisition and phase-locked loops (PLLs) for carrier tracking.

Digital IF signals represent the first step in GPS signal processing. Through sampled and digitized intermediate frequency signals, the program can simulate the signal processing flow of real hardware. Subsequent algorithms include critical techniques such as carrier stripping, code correlation, and integrate-and-dump operations, which are essential for understanding the demodulation and decoding processes of GPS signals. Code implementation typically involves complex multiplication for carrier removal and PRN code correlation for signal synchronization.

Navigation data decoding involves GPS satellite ephemeris data, time information, etc., which are used to calculate satellite positions and velocities. Pseudorange measurement estimates the distance between the receiver and satellites through signal propagation time calculation. Ultimately, by combining pseudorange data from multiple satellites, algorithms like least squares methods are employed to compute the receiver's precise position. The positioning algorithm implementation includes satellite position computation using ephemeris parameters and navigation solution using matrix operations for position estimation.

For developers or researchers learning GPS technology, this MATLAB program provides extensive reference materials. It not only helps understand the overall GPS signal processing workflow but also enables in-depth exploration of key algorithm implementations, such as code phase synchronization and carrier loop tracking. By adjusting code parameters, users can simulate receiver performance under different signal conditions, making it an ideal tool for GPS technology learning and research. The codebase offers modular functions for each processing stage, allowing easy experimentation with algorithm variations and parameter tuning.