High precision GNSS uses error correction techniques to improve locational accuracy to around 10cm, allowing new applications for the automotive industry, including C-V2X and autonomous driving. This video explains the principles of high precision GNSS, describes the sources of errors and how they are corrected as well as how correction data is distributed via the cellular network and satellite communications. It then shows how to test the high precision GNSS throughout the integration chain from chipsets to modules and vehicles, including details of specific test scenarios and solutions. The video concludes with a summary of high-precision GNSS capabilities and challenges as well as the role of testing in ensuring reliability, particularly for safety-critical applications.