cET 318 6. observable and error Sources The Slxth Lecture 6. Observable and error 1. GPS Error Source? 2. How to improve the Observation Sources Book:p.87-129 Dr Guoqing Zhou 1. 1 Error Categories 1. Errors related to GPs Satellites 2. Errors related to GPS signal propagation 1. Error Sources 3. Error related to GPS receivers 1. Errors Related to GPs Satellites 1. 2 Basic Measurement of Eliminating These errors Relativistic effect 2. Errors Related to GPS Signal Propagation ionospheric refraction 2. Observation Approaches(relative surveying, Multi-path effect 3. GPS Receiver Selection( Hardware: good antenna 3. Error Related to GPS Receivers · Receiver clock error Receiver position Antenna geometric center1 Dr. Guoqing Zhou 6. Observable and Error Sources CET 318 Book: p. 87-129 6. Observabnle and Error Sources 1. GPS Error Source? 2. How to improve the Observation Accuracy? 1. Error Sources 1.1 Error Categories 1. Errors related to GPS Satellites 2. Errors related to GPS signal propagation in atmosphere 3. Error related to GPS receivers 1. Errors Related to GPS Satellites • Ephemerides error • Clock error • Relativistic effect 2. Errors Related to GPS Signal Propagation • Ionospheric refraction • Tropospheric refraction • Multi-path effect 3. Error Related to GPS Receivers • Receiver clock error • Receiver position • Antenna geometric center 1.2 Basic Measurement of Eliminating These Errors 1. Correction by Models 2. Observation Approaches (relative surveying, DGPS), Observation Time (time, date) 3. GPS Receiver Selection (Hardware: good antenna for multipath, avoid building