A Text Book on GPS Surveying

Book excerpt: The objective of this book is to provide insights into understanding GPS Surveying and positioning concisely in a systematic manner. The book contains six chapters, one annexure followed by bibliography. The first chapter aims at introducing Global Positioning System (GPS) for land surveying. It starts with a brief history of development of NAVSTAR (NAVigational System for Timing And Ranging) GPS followed by advantages of GPS in land surveying and principle of positioning using GPS. The chapter concludes with an overview of elements of GPS in surveying and positioning. The objective of Chapter 2 is to provide basic information about GPS for surveying. It starts with architecture of GPS followed by contents of GPS signal, GPS system time. It discusses the World Geodetic System 1984 (WGS84) explaining its coordinate system, geoid, ellipsoid, earth gravitational model etc followed by its relationships with other geodetic systems. The chapter also discusses on GPS augmentation systems and modernization steps. Chapter 3 aims at providing fundamental information required for GPS surveying. The chapter explains the different methods for GPS surveying, equipments, field operations and quality analysis of GPS observations. The chapter concludes with accuracy standards to be followed for GPS surveying. Aim of chapter 4 is to explain the content of GPS observations. It discusses the GPS observables and fundamental relations to determine unknown positions. It also provides the different errors associated with observations. The chapter concludes with criterion for assessment of quality of GPS Observables. Chapter 5 discusses processing steps involved in determination of positions from GPS observables. It explains the operations involved in pre-processing and positioning followed by criterion for assessment of GPS positions. The chapter concludes with a brief discussion on salient modules of a GPS data processing software. Chapter 6 aims at locating GPS position geo-spatially through network adjustment. It discusses least square network adjustment models and methods, processing strategies, steps for network adjustments and criterion for output quality. The chapter concludes with a worked out example on network adjustment, as detailed theoretically. The book further contains one annexure stating the steps involved for conversion of navigation data to determine satellite positions in ECEF system. Towards the end, the book contains a list of books which have been referred in writing this book. Manuscript has been thoroughly checked through plagiarism software to avoid any copyright violation. However, to make the book more understandable, standard names and symbols have been used from original literatures. To summarize, the book provides a sequence of topics aiming to basic understanding and carrying out land surveying as well as processing for geo-spatial positioning using GPS. The book is meant to serve as an introductory text book on GPS surveying and is expected to be useful for students as well as field surveyors looking for insights into GPS surveying.