Province of British Columbia (BC) 
                                        
                      Guidelines for RTK GPS Surveys, 
                                  Including  
            Operating within a Municipal Active Control System 
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                               Area (BC ACS ) 
                                                                    
                                                                    
                                                                    
                                                                    
                                                                    
                                                                    
                                                                    
                                                                    
                                                                    
                                                                    
                                                                    
                                                                    
                                                                    
                                                                    
                                                       
                                        
                                   Version 1.2 
                                  November 2009
                        British Columbia Guidelines for GPS RTK Surveys,  
                                                                                                  m
                        Including Operating within a Municipal Active Control System Area (BC ACS )                                      
                                                                                 
                         
                                                                       Table of Contents 
                        LIST OF FIGURES ......................................................................................................................................II 
                        APPENDICES ..............................................................................................................................................II 
                        1    INTRODUCTION .................................................................................................................................. 1 
                        2    GPS RTK SURVEYS ............................................................................................................................. 1 
                             2.1    RTK DESCRIPTION ......................................................................................................................... 1 
                             2.2    RTK ACCURACY ISSUES ................................................................................................................ 2 
                               2.2.1  RTK Antenna Centering and HI Measurement                                                         3 
                               2.2.2  RTK Antenna Phase Center Movement                                                                4 
                               2.2.3  RTK Base Station Fixed 3D Coordinates                                                            4 
                               2.2.4  RTK Initialization                                                                               4 
                               2.2.5  Satellite Geometry and Elevation Angles                                                          6 
                               2.2.6  Random and Short-Term Systematic RTK Errors                                                      6 
                               2.2.7  Radial Nature of RTK Surveys                                                                     7 
                             2.3    RTK VALIDATION .......................................................................................................................... 8 
                             2.4    RTK PRODUCTION SURVEYS .......................................................................................................... 9 
                               2.4.1  Horizontal Datums, Coordinates, and Projections                                                  9 
                               2.4.2  Vertical Considerations (Ellipsoidal Heights, MSL Elevations, Geoidal Undulations)             10 
                               2.4.3  Planning and Preparation for an RTK Survey                                                     10 
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                        3.     MUNICIPAL ACTIVE CONTROL SYSTEMS:  BC ACS  ....................................................... 12 
                             3.1.   HISTORY ....................................................................................................................................... 12 
                             3.2.   WHAT IS THE BC ACSM ?.............................................................................................................. 14 
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                             3.3.   BC ACS  COMPONENTS ............................................................................................................... 14 
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                             3.4.   BC ACS  ADVANTAGES .............................................................................................................. 15 
                             3.5    RTK CONTROL SURVEYS WITHIN A BC ACSM ............................................................................. 15 
                               3.5.1  RTK Antenna Centering and HI Measurements:                                                     15 
                               3.5.2  RTK Antenna Phase Center Movement:                                                             16 
                               3.5.3  RTK Base Station Fixed 3D Coordinates:                                                         16 
                               3.5.4  RTK Initialization:                                                                            16 
                               3.5.5  Satellite Geometry and Elevation Angles:                                                       16 
                               3.5.6  Random and Short-Term Systematic RTK Errors:                                                   17 
                               3.5.7  Radial Nature of RTK Surveys:                                                                  17 
                               3.5.8  Validations:                                                                                   17 
                               3.5.9  Horizontal Datums, Coordinates, and Projections:                                               17 
                               3.5.10 Vertical Considerations (Ellipsoidal height, MSL elevation, Geoidal undulation):               18 
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                               3.5.11 Planning and Preparation for an RTK Survey within an Acs :                                     19 
                        Crown Registry and Geographic Base Branch                                              Issue: 1.1 – Revision Date: 10/22/09 
                        ISO CRGB Procedures Manual V4.5 JA04 wCBM.doc                                                                       Page i 
                                            
                        CRGB-ISO-DO-001
                        British Columbia Guidelines for GPS RTK Surveys,  
                                                                                                  m
                        Including Operating within a Municipal Active Control System Area (BC ACS )                                      
                                                                                 
                         
                         
                        List of Figures 
                         
                        Figure 1: Typical RTK GPS system setup.................................................................................................... 2 
                        Figure 2: BC ACS Stations ......................................................................................................................... 13 
                         
                        Appendices 
                         
                        Appendix A         -        CRGB Documents 
                         
                        Appendix B         -        References 
                         
                        Appendix C         -        Recommended Information Sources 
                        Crown Registry and Geographic Base Branch                                              Issue: 1.1 – Revision Date: 10/22/09 
                        ISO CRGB Procedures Manual V4.5 JA04 wCBM.doc                                                                      Page ii 
                                            
                        CRGB-ISO-DO-001
                        British Columbia Guidelines for GPS RTK Surveys,  
                                                                                                  m
                        Including Operating within a Municipal Active Control System Area (BC ACS )                                      
                                                                                 
                         
                        1  INTRODUCTION 
                        This document provides guidelines for GPS Real Time Kinematic (RTK) surveys conducted within BC. 
                        Referrals to this  document should be with the British  Columbia  Specifications and Guidelines for 
                        Control Surveys Using GPS Technology. It is assumed that the reader has an understanding of the GPS 
                        Control Surveys document before this RTK guideline document is read. Appendix B contains information 
                        links to obtain documents maintained by Base Mapping and Geomatics Services (CRGB) of the Ministry 
                        of Agriculture and Lands. 
                        In these documents, it is assumed that static carrier-phase surveys are used for the reliable establishment 
                        of permanent survey control that will be fully integrated within the Provincial Geo-Spatial Reference 
                        (GSR). RTK techniques are suitable for topographic / detail / layout surveys, and can also be used for 
                        survey control establishment in support of specific projects.  The accuracy expectation for RTK  is 
                        typically a few-centimetres horizontal and perhaps 1.5 times worse in the vertical. Accuracy values are 
                        expressed at the 95% confidence level in this document.  
                        Section 2 of this document describes general techniques and accuracy issues for RTK surveying.  
                        Section 3 of this document describes the specific RTK application of working within a Municipal Active 
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                        Control System area (BC ACS ). The Capital Regional District (CRD), and the Metro Vancouver (MV) 
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                        are example BC ACS operational areas. The High Precision Networks (HPN) established as part of the 
                        BC ACSm initiatives are also discussed in this Section. Note that Section 3 is “generic” for RTK users 
                        working within a BC ACSm. Operational details (e.g. current system configuration, data communication 
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                        details, contact names, etc.) are available directly from the agency looking after each specific BC ACS . 
                         
                        2    GPS RTK SURVEYS 
                        This Section describes GPS RTK surveys, including methodologies, procedures, errors, redundancy 
                        issues, etc. IMPORTANT NOTE: It is assumed that the reader has an understanding of the document: 
                        British Columbia Specifications and Guidelines for Control Surveys Using GPS Technology. 
                         
                        2.1      RTK Description 
                         
                        Real Time Kinematic (RTK) surveying is an advanced form of relative GPS carrier-phase surveying in 
                        which the Base Station transmits its raw measurement data to rover(s), which then compute a vector 
                        baseline from the Base Station to the rover.  This computation is done nearly instantaneously, with 
                        minimal delays between the time of the Base Station measurements, and the time these are used for 
                        baseline processing at the rover (ideally a few seconds). The precision of RTK baselines can be almost as 
                        good as the precision of static carrier-phase baselines. If the Base Station coordinates are accurately 
                        known,  this  will usually result in accurate rover  positions.  The combination of fast and precise 
                        positioning, one-man operation, and wide work areas has resulted in RTK becoming an impressively 
                        powerful tool for some survey applications. Like other survey techniques, RTK does not solve every 
                        survey problem. RTK is only suitable for environments with reasonably good GPS tracking conditions 
                        (limited obstructions, multipath, and RF noise), and with continuously reliable communication from the 
                        Base Station to the rover. 
                        Crown Registry and Geographic Base Branch                                             Issue: 1.1 – Revision Date: 11/5/2009 
                        ISO CRGB Procedures Manual V4.5 JA04 wCBM.doc                                                                             
                        CRGB-ISO-DO-001                                                                                                    Page 1