Continuously Operating GPS Reference Network Jim Waters, PE, RLS Assistant Director, Design Division
TDOT began discussions internally about a possible Continuously Operating Reference Network in 1999 2000. TDOT initiated conversations with NGS concerning CORS monumentation requirements in June 2000. Initial discussions involved use of a P BAR stand alone monument for reference stations. TDOT staff began an effort to secure funding for the project. Funding was secured in fiscal year 2003 2004.
TDOT Staff met with Internal Purchasing Staff. Invitation To Bid process required due to procurement of equipment. 2003 Point of Beginning Magazine GPS Equipment Survey. Invitations sent to all possible vendors (six) that provided survey grade GPS. Five vendors agreed to demonstrate their systems in December 2003 & January 2004. One Day presentations to TDOT Staff. One Day Field Demonstrations of GPS Long Baselines and Short Baselines.
GPS Base Station at TDOT Point located at Exit 172 on I 40. Base Line Distances ranged from 45 KM (28 Miles) to 5 KM (3.4 miles) Rover computed various TDOT control points. Results: Thales Navigation Communication Problems Topcon Positioning Systems Communication Problems Eagle Point Calculated Positions See Chart Sokkia Declined from Participation Leica Geosystems Calculated Positions See Chart Trimble Navigation Calculated Positions See Chart
Horizontal Error 0.60 0.50 Value Undermined (Point Next to Bldg) Trimble Only Horizontal Distance from Known Values (feet) 0.40 0.30 0.20 0.10 Eagle Point Leica Trimble 0.00 Exit 169 GPS 28 Exit 182 Exit 188 Exit 196 Exit 201 19 07 Region 19 03 19 06 19 05 19 04 19 02 19 01 Point Number
Vertical Error 0.80 Vertical Distance from Known Values (feet) 0.60 0.40 0.20 0.00 0.20 0.40 Value Undermined (Point Next to Bldg) Trimble Only Exit 169 GPS 28 Exit 182 Exit 188 Exit 196 Exit 201 19 07 Region 19 03 19 06 19 05 19 04 19 02 19 01 Eagle Point Leica Trimble 0.60 0.80 Point Number
Specifications were developed based on all demonstration results. State of Tennessee, Department of General Services, Purchasing Division reviewed process, and recommended changes to specification, and required additional testing under their guidance with specific passing criteria. Delays occurred during their review due to heavy personnel turnover in their Department.
Pre Bid Meeting was held October 2005. After Pre Bid Meeting, a Qualified Product Testing Criteria test was performed in November 2005. The following manufacturer s participated: Leica Geosystems Trimble Navigation Eagle Point Topcon Positioning Systems
Where We Started Leica Geosystems Topcon Positioning Systems Trimble Navigation Eagle Point
Four vendors tested in the following areas: Documents Letters of Reference Antenna Calibration General Vendor Documentation GIS Accuracy Horizontal Only with WAAS Correction GPS Accuracy Horizontal & Vertical Accuracy from Portable GPS Base. Communication Initialized, Receiving Corrections, and Ambiguities Resolved within 15 minutes of cold start. Baseline Lengths Tested 41.1 KM (26 Miles) 49.7 KM (31 Miles) 65.6 KM (41 Miles) All vendors met specifications when testing All Vendors Failed Some Portion of the Test.
5.0 QPTC November 2005 GIS Horizontal Error 4.5 4.0 Distance From True Position (feet) 3.5 3.0 2.5 2.0 1.5 Allowable Leica Trimble Eagle Point Topcon 1.0 0.5 0.0 GPS 11 GPS 12 GPS 27 GPS 28
QPTC November 2005 GPS Horizontal 0.30 0.25 Distance From True Position (feet) 0.20 0.15 0.10 Allowable Leica Trimble Eagle Point Topcon 0.05 0.00 GPS 11 GPS 12 GPS 27
QPTC November 2005 0.40 GPS Vertical 0.30 0.20 Distance From True Position (feet) 0.10 0.00 0.10 GPS 11 GPS 12 GPS 27 Allowable Leica Trimble Eagle Point Topcon Allowable 0.20 0.30 0.40
QPTC November 2005 GPS Fixed Position Time 20.00 18.00 16.00 14.00 Time (minutes) 12.00 10.00 8.00 Allowable Leica Trimble Eagle Point Topcon 6.00 4.00 2.00 0.00 GPS 11 GPS 12 GPS 27 GPS 28
A Second Pre Bid Meeting was held February 2006. After Pre Bid Meeting, a Qualified Product Testing Criteria test was performed in February and March 2006. The following manufacturer s participated: Leica Geosystems Trimble Navigation Eagle Point Topcon Positioning Systems Sokkia
Leica Geosystems Trimble Navigation Eagle Point Topcon Positioning Systems
Five vendors tested in the following areas: Documents Letters of Reference Antenna Calibration General Vendor Documentation GIS Accuracy Horizontal Only with Correction From Portable GPS Base. GPS Accuracy Horizontal & Vertical Accuracy From Portable GPS Base. Time Constraint Removed. Baseline Lengths Tested 34.4 KM (21 Miles) 49.7 KM (31 Miles) 59.8 KM (37 Miles)
Vendors passing the Documents Portion of the Testing: Leica Geosystems Trimble Navigation Eagle Point Topcon Positioning Systems Vendors passing the GIS Accuracy Portion of the Testing: Leica Geosystems Trimble Navigation Eagle Point Topcon Positioning Systems Vendors Passing the GPS Accuracy Portion of the Testing: Leica Geosystems Trimble Navigation Eagle Point Topcon Positioning Systems
3.5 QPTC February 2006 GIS Horizontal Error 3.0 Distance From True Position (feet) 2.5 2.0 1.5 1.0 Allowable Leica Trimble Eagle Point Topcon 0.5 0.0 GPS 11 GPS 27 GPS 28
QPTC February 2006 GPS Horizontal 0.3 0.2 Distance From True Position (feet) 0.2 0.1 Allowable Leica Trimble Eagle Point Topcon 0.1 0.0 GPS 11 GPS 27 GPS 28
0.30 QPTC February 2006 GPS Vertical 0.20 Distance From True Position (feet) 0.10 0.00 0.10 GPS 11 GPS 27 GPS 28 Allowable Leica Trimble Eagle Point Topcon Allowable 0.20 0.30
Where We Are TDOT has ordered the following items from the contract: Training: 2 Portable GIS/GPS (Mapping Grade) Receiver Field and Office Training Classes 1 GPS Network Software Training Classes 8 GPS Field System Training Classes 3 GPS Office Processing Training Classes Additional Equipment & Software will be purchased as necessary from other TDOT Divisions. Additional Equipment & Software can be purchased from other State of Tennessee Agencies.
Compliance with Specifications Leica Geosystems did not comply with the specifications during testing. Eagle Point did not comply with the specifications during testing. Protest Hearings: Leica Geosystems April 18, 2006. Eagle Point April 19, 2006. Department of General Services Commissioner s representative reviewed data during hearings, and denied the protest.
Receiving ITB Packets Trimble Navigation Topcon Positioning Systems Bid Opening on May 31, 2006. Problems with the Bid Protest Hearings Topcon Positioning Systems July 31, 2006. Trimble Navigation September 6, 2006 Receiving Revised ITB Packets Trimble Navigation Topcon Positioning Systems Bid Opening on September 25, 2006. Contract Awarded to Hayes Instrument / Topcon Positioning Systems October 20, 2006.
Where We Are
Where We Are TDOT has ordered the following items from the contract: Hardware: 22 Topcon GPS Reference Stations (NET G3 receivers, G3 A1 Geodetic Antennae, and necessary Antenna Cabling). 30 Topcon Portable GPS Rovers with internal modems and radios (GR 3) 20 Topcon Portable GPS Base Stations with internal modems and radios (GR 3). 9 Topcon GMS 2 GIS receivers (1 for Information Technology Division, GIS Section, 4 for Design Division & 4 for Environmental Division). Software: TopNET Software for 25 Reference Stations and 75 GPS Rovers. 17 Seats of Topcon Tools Survey. 11 Seats of Topcon Tools GIS.
Where We Are TDOT CORS Network 40 KM (25 Mile) Radius Circles
Where We Are Installations complete at 22 TDOT District Offices and Regional Offices. Installations were completed in about ½ working day. Chattanooga Area does not have an installation yet. TDOT staff are seeking a suitable State facility to locate the Chattanooga Reference Station. Additional Reference Station sites are also being identified to fill in areas without coverage. Equipment met accuracy standards up to 60 KM during testing, however 40 KM spacing is being used for redundancy.
Where We Are TDOT staff have begun training on Topcon Equipment (GR 3) and Software (Topcon Tools). TDOT Staff will begin training next week on TopNET Network Software. Training Classes will be tweaked, and all TDOT Design Division Surveyors will receive training on Portable Base and Portable Rovers. Additionally, agendas for Topcon GIS equipment (GMS 2) and software (Topcon Tools GIS) are being developed. All TDOT Divisions will take these training classes for items they purchase, as necessary.
Where We Are TDOT Environmental Division staff have received their GMS 2 receivers and their Topcon Tools Software. TDOT Design Division has received all of the equipment and software previously listed. TDOT staff will begin using the equipment as soon as possible after their training sessions.
Where Are We Going Continued installation of GPS Reference Stations as necessary. Coordination with National Geodetic Surveys to obtain positions for all TDOT CORS Network Reference Stations. All TDOT CORS Network Reference Stations will be a part of the National CORS Network. Modifications are planned to TDOT surveying procedures to incorporate RTK Surveying procedures using the TDOT CORS Network and Portable GPS Base Stations.
Where Are We Going TDOT CORS Network will have the ability to use any vendors equipment. Testing will be performed to ensure compatibility of the TDOT CORS Network with all manufacturers equipment. TDOT will test the procedures developed for RTK Surveying using the TDOT CORS Network to ensure its accuracy and reliability. TDOT Plans to offer use of the TDOT CORS Network to contractors and consultants under contract with TDOT on our projects. TDOT is working with TDOT legal office concerning public access to the TDOT CORS Network.
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