Accuracy and precision of GNSS in the field

Abstract Global Navigation Satellite System (GNSS) technologies are now ubiquitous in everyday life, being incorporated in our everyday electronic devices, and are used by the public, surveyors, and geoscientists on a regular basis. For geoscientists conducting research based on GNSS technologies, it is vitally important to understand the implications of the accuracy and precision of the wide gamut of GNSS options available, from the mobile device to precision surveying instruments. In this chapter, we discuss the theoretical understanding of the terms accuracy and precision and the impact they have on survey design. We provide guidance on the different levels of accuracy or precision that can be achieved by different GNSS instrument types and the concept of economy of accuracy in device choice. We discuss the impact of the environment on GNSS results and highlight the need to understand datums and projections when surveying. We conclude the chapter by providing real example scenarios to add a practical context to the chapter.