1. InCORS INDIANA’S STATEWIDE GNSS-GPS REAL TIME NETWORK Presented by Eric N Banschbach, PLS Land & Aerial Survey Office 97 th Annual Purdue Road School March 9, 2011

2. Indiana Continuously Operating Reference Station Network Network of 45 geodetic quality GPS (GNSS) receivers and antennas, permanently installed, located across the state – INDOT & ISP sites Continuously collects GPS data Transmits thru Internet to central servers Data archived for future use, available for download by users Data processed by server software to generate network corrections- available via internet in real-time What is the InCORS Network?

3. Eliminates need for user to setup local base station Allows mitigation of systematic errors −Modeling atmospheric & orbital corrections −Increases Positional Accuracies Strong redundancy in the network because of the use of multiple reference stations Robust against single reference station failure −Hardware or Communications failures Monitors its own integrity and can detect problem with reference station Benefits of an RTN

4. Accuracies of computed rover positions are more homogeneous Accuracy is maintained over larger distances between reference station and rover Operational range from short baseline lengths increased to long baseline lengths Capable of survey grade accuracies (cm/sub-cm) Provides consistent established reference coordinate frame Supports multiple rover users and applications AG, Machine Control, GIS, Resource Mngt, and more Benefits of an RTN

5. Reduction in staff-hours and equipment = Cost Savings −Only requires a rover receiver system −Eliminates time for site selection −(Daily) set-up time required −Security concerns - No baby-sitting base station −Power supply issues −Increased speed of initialization time over long distances Avoids common errors in local base station setup −Set up on wrong station −Incorrect coordinates entered for base −Incorrect antenna height measurement −Incorrect antenna type selected for processing −Inadvertent movement or disturbance − (wind, bumped, etc) −Interference with signal −multipath Advantages of RTN Surveying

6. Components of the InCORS Network

7. 4 main parts: GNSS Hardware GNSS Software Monumentation Communication 4 main parts: GNSS Hardware GNSS Software Monumentation Communication GNSS Spider Software Communication Data Links Monumentation Installation GNSS Hardware InCORS Components

8. GNSS Hardware GNSS Hardware is the key component for functionality in communication, interface with Server Software, Satellite Constellation, Receiver Clock, and Flexibility for remote communications. 1202 GG Leica Antenna GRX1200GG PRO Leica Receiver InCORS Hardware

9. GNSS Spider Software Leica SpiderNet Modular and fully scalable For single and multiple stations INDOT 45 stations Room to grow to 60 For small and large networks For Post-Processed and RTK Networks For all types of GPS receivers Leica, Trimble, Ashtech, TopCon…. For all communication methods InCORS Software

10. Monumentation Installation InCORS Monumentation 3 Concrete Monuments - permanent 42 Building Mounts – semi-permanent 5 stations on ISP facilities 34 stations have been accepted by NGS as National CORS thus far (NGS monitored)

11. Communication Data Links GSM/GPRS Repeaters Cell Phones w/ data plan GSM/GPRS & CDMA Modems MiFi Device GPS Signals Antenna Receiver Box IOT Network INDOT Servers Cellular Network Cellular Receiver End User InCORS Communication

12. InCORS Network Details

13. DOT-Owned and Managed Land & Aerial Survey Office (LASO) Utilizes state IT Communications Network Free Access to Public & Private Sector Provides Statewide Coverage Open Architecture (RTCM 2.3,3.1,CMR,CMR+) Public use started on February 1, 2010 Currently have created over 750 accounts Sharing station data with Michigan & Kentucky 34 stations currently on available on NGS CORS InCORS Network Details

14. ANDS WLCI PRDU IUCO VINU Pre InCORSInCORS Coverage State Coverage

15. Average Usage

16. Website Information

17. (http://www.in.gov/indot/) Indiana DOT Web Site

18. (http://www.laso.indot.in.gov) Land and Aerial Survey Office Web Site

19. (http://incors.in.gov) Welcome Page Contains: Brief description Links to: Station Location Map Data Page RTK info & instructions System Status page InCORS Web Site

20. InCORS – Station Location Map Click on station icon to bring up metadata

21. InCORS – Data Page Contains: Link to the ftp site for Rinex data Link to the Data and Website Disclaimer

22. Contains: How to get access Link to the RTK User Agreement Links to RTK documents Submittal information for User Agreement User tech support note Preferred method of contact: email to incors@indot.in.gov InCORS – Real Time (RTK) Page

23. InCORS – RTK User Agreement

24. InCORS – System Status Page

25. InCORS Network Broadcast Corrections

26. 26 Two types of corrections Nearest Site Automatic Cell Nearest Site Correction Single Baseline Solution CMR, CMR+, RTCM 2.3, RTCM 3.1 available PPM errors increase with rover distance from base Network software automatically selects the closest reference station to the rover based on the submitted NMEA message Automatic Cell Network Solution CMR+, RTCM 2.3, RTCM 3.1 available with MAX and iMAX Network software automatically selects the closest reference station and then uses it and next five nearest stations to model corrections Helps to minimize PPM errors due to rover distance from base Broadcast Corrections

27. Nearest Solution (Single Baseline)

28. Automatic Cell

29. NGS National CORS

30. NGS National CORS Approved Sites All 45 InCORS stations have been submitted to NGS for approval 34 stations accepted Of the remaining 11 submitted stations 6 stations given preliminary approval 5 stations under further review due to data quality concerns

31. NGS National CORS Why is NGS Approval Important? Adds stations to OPUS solutions Rinex data is available through NGS’s User Friendly CORS Application http://www.ngs.noaa.gov/UFCORS/ Rinex data available for longer duration Process of obtaining the Rinex data easier One location for Rinex data Currently the NGS software only supports GPS Satellite Rinex data, in the first quarter of 2011 a software upgrade will support GNSS Satellite Rinex data Monitoring of stations for movement

32. For Questions/Issues e-mail: incors@indot.in.gov Eric Banschbach, PLS Manager – Land & Aerial Survey Office ebanschbach@indot.in.gov 317-610-7251, ext. 205 Derek Fuller, PLS Survey Program Coordinator InCORS Administrator dfuller@indot.in.gov 317-610-7251, ext. 293 Contact Information