Precise Point Positioning: Multi-Constellation Ionospheric-Free Positioning Using L1/L5 Frequencies on a Low-Cost Receiver

Abstract

This thesis revolves around the area of satellite-based positioning using Global Navigation Satellite System (GNSS) signals from the Global Positioning System (GPS) and Galileo constellations. GNSS positioning plays a vital role in daily life, particularly in applications like navigation and timing. This project aims to develop a high-accuracy, Precise Point Positioning (PPP) solution using data from a low-cost receiver. To achieve this an ionosphere-free measurement combination based on L1 and L5 frequencies is ex plored instead of the conventional choice of L1 and L2. The research investigates the impact of different error sources, such as biases and atmospheric disturbances, on the accuracy of PPP. An Extended Kalman Filter (EKF)-based solution that incorporates offline corrections, cycle slip detection, and ambiguity resolution is proposed. The hardware used for data collection is the u-blox evaluation kit EKV-F9P which includes the GNSS receiver module ZED-F9P and an antenna. This low-cost dual-frequency hardware is proven to provide accurate data to implement a high-accuracy PPP solution. When enough satellites are visible, the results demonstrate a decimetre-level accuracy for sta tionary positioning estimation. However, due to the limited availability of L5 frequency signals, continuous precise positioning is not always possible. Despite this limitation, the work contributes to advancing GNSS positioning technology and lays the groundwork for future enhancements in PPP-based applications.