GNSS Receiver Main Program MATLAB Source Code

The GNSS receiver main program serves as the core processing unit of satellite navigation systems, performing critical functions including signal acquisition, tracking, and final positioning calculation. Implementing this process in MATLAB enables researchers and engineers to efficiently validate algorithms and optimize performance through code-based simulation and testing. Signal Acquisition In GNSS receivers, signal acquisition aims to detect the presence of satellite signals and provide initial estimates of their frequency and code phase. MATLAB implementations typically employ parallel frequency search and code correlation operations. The algorithm scans through possible frequency offset ranges and performs correlation calculations with locally generated pseudorandom codes using functions like xcorr or custom correlation implementations to determine signal detection. Code implementation often involves frequency domain processing using FFT for efficient parallel search across multiple frequency bins. Signal Tracking Once signals are acquired, the receiver enters the tracking phase, typically employing Phase-Locked Loops (PLL) and Delay-Locked Loops (DLL) to achieve precise carrier and code synchronization. MATLAB tracking algorithms continuously adjust local signal generation parameters through feedback control systems, maintaining synchronization with received signals to ensure accurate subsequent data demodulation and pseudorange measurements. The implementation commonly includes PLL/DLL discriminators, loop filters, and numerically controlled oscillators (NCOs) configured with appropriate bandwidth parameters for different dynamic conditions. Positioning Calculation After achieving stable tracking, the receiver extracts navigation information from multiple satellites (including ephemeris data, pseudoranges, etc.) and performs position computation using least squares methods or Extended Kalman Filters (EKF). MATLAB programs process multi-satellite data, optimize Geometric Dilution of Precision (GDOP), and ultimately output the receiver's three-dimensional coordinates (longitude, latitude, altitude) along with timing information. The positioning algorithm implementation typically involves satellite position calculation from ephemeris data, pseudorange measurement processing, and navigation solution computation with covariance analysis for accuracy assessment. This MATLAB implementation of the main program is suitable not only for educational and research purposes but also for practical GNSS receiver prototype validation, providing a comprehensive framework for algorithm development and performance evaluation through modular code structure.