A Satellite Navigation System provides continuous positioning over the globe. The system architecture is primarily defined by the Space Segment, which consists of orbiting Satellites. The satellites’ payload generates and transmits the code and carrier phase signals, along with the navigation message. Modernisation efforts continuously enhance these signals; for instance, the GPS third civil signal L2C is a robust signal designed to facilitate Mass Market (low-cost) receivers. Similarly, Glonass satellites are undergoing a GLONASS signal CDMA upgrade for civilian applications on the G3 band. The core function relies on sophisticated algorithms to produce navigational outputs. The receiver solves navigation equations to perform Positioning Velocity Time (PVT) computation, delivering the user's coordinates, velocity, and precise timing. The geometric quality of the position solution is quantified using the Dillution of Precision (DOP) factor. Depending on the required precision, receivers are classified into different grade levels, ranging from mass-market devices to professional grade and scientific (geodetic) grade equipment used to achieve high-accuracy positioning, often striving for centimetre-level results or better.