LINCOLN COUNTY LAND INFORMATION & CONSERVATION DEPARTMENT Lincoln County Service Center 801 N Sales Street-Suite 105 Merrill, WI 54452

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1 LINCOLN COUNTY LAND INFORMATION & CONSERVATION DEPARTMENT Lincoln County Service Center 801 N Sales Street-Suite 105 Merrill, WI Phone (715) Fax (715) Date: September 27, 2011 To: From: RE: Interested GPS and/or Survey Firms Tony Dallman Lincoln County Surveyor Telephone: (715) Fax: (715) tdallman@co.lincoln.wi.us Lincoln County s Remonumentation Program Request For Proposal (RFP) For Remonumentation and GPS Services Lincoln County Land Information & Conservation Department is seeking proposals from persons or firms for surveying services as outlined in the attached Request for Proposal. The project will consist of the reestablishment of the Public Land Survey System (PLSS) corners, a U.S. Public Land Survey Monument Record, along with GPS coordinates in the Lincoln County Coordinate System. This information will serve as the basis for digital parcel mapping control. The project area is located in the Town of Somo (T35N R4E) and the Town of Wilson (T35N R5E) Lincoln County, Wisconsin. Due to the lack of historical evidence in this area, this project may require meetings with landowners throughout the project. Lincoln County staff will facilitate these meetings with the contractor. Projected schedule of procurement: RFP published and available: October 4 th, 2011 Deadline for clarification: October 12th, 2011; 4:30 PM, CDT Proposal Deadline: Submission Date: October 27th, 2011 Submission Time: 4:00 PM, CDT Bid Opening: October 27th, 2011 at 4:15 PM, CDT at the Lincoln County Land Information and Conservation Department Contract award: At Land Information, Conservation & University Extension Committee Meeting November 9 th, 2011, 10:00 AM 1

2 Request for Proposal On the Establishment of Public Land Survey System Corners Using GPS Surveying Methods for Town 35 North, Ranges 4 & 5 East, Lincoln County, Wisconsin A. Scope of Services 1) Lincoln County is requesting proposals for approximately 49 Public Land Survey corners for which we have no U.S. Public Land Survey Monument Record in Town 35 North Range 4 East and Town 35 North Range 5 East. The County and its representatives will select the corners to maximize parcel-mapping accuracy within the project area. The County will supply the Contractor with all the necessary monuments and accessories and all fieldwork shall be completed during the most productive time of the year. 2) This project will include the recovery and verification of or remonumentation of all PLSS corners, for this project, including section, quarter section and meander corners. If the original PLSS corners are not recoverable, the Contractor shall determine the status thereof under the United States Public Land Office definitions and shall follow the prescribed procedures of that office in their relocation. The Lincoln County Surveyor will confirm the final location of all section, quarter section and meander corners. 3) The Contractor shall furnish all services, labor, transportation, lodging, per diem and other related expenses necessary to conduct and complete the work, and shall furnish all materials, equipment, vehicles, supplies and incidentals other than those which are hereinafter specifically designated to be furnished by others. The Contractor shall be an independent contractor, not an employee or agent of the County. 4) The Contractor shall attend meetings, facilitated by the County, with landowners to aid in corner locations and recovery. The meetings will include evidence found by the Contractor and any evidence the County and or landowners may have. 5) The County requires the following deliverables: a) A map showing each corner location and its representation within the Town. The map shall include a certification from a Wisconsin Registered Land Surveyor to the positional accuracy of the corners observed along with related survey map information. b) Final Report c) Coordinate tables (Lincoln County, Feet, NAD 83/91) d) A completed Section Subdivision for all Sections worked in and a U.S. Public Land Survey Monument Record (A-E 7.08) (3) (a)(b)(c)(d)(e)(f)(g)(h)(i) for every corner reestablished or found for this Project. e) Hard copies of all above mentioned material along with digital copies of the material mentioned in (A) (5) (a)(b) & (c). f) Photographs of each PLSS Corner and a photograph in each cardinal direction at each corner, included in this Project, in a digital format. 2

3 B. Project Description 1. This project is located in Town 35 North, Range 4 East, Town of Somo and Town 35 North Range 5 East, Town of Wilson; Lincoln County, WI. Land cover for the Towns of Somo and Wilson are forested with areas of mixed rural open land. The County can provide an ARC INFO file of the project area s roads and water bodies to aid in depicting the cartographic features of the project area. 2. All fieldwork, with respect to the location and relocation of all the aforementioned corners, shall be based upon the assembly of all authoritative information from Lincoln County records such as title documents, private and public survey records, existing monumentation, testimonial evidence and occupation evidence that may be useful in determining the actual location of the PLSS corners and all other corners as well as the proper analysis of this information to arrive at the best determination of the actual location of said corners. Due to the lack of historical evidence in this area of the County, the County will facilitate meetings with the Contractor and landowners to aid in the establishment of said corners. Proper performance in this regard depends largely upon knowledge of the PLSS corner remonumentation procedures and practices, conditions and laws of boundaries and titles. For these reasons, all work must be performed by competent, qualified registered land surveyors and technicians experienced in the remonumentation of the corners of the PLSS. C. Scope of GPS Method 1. All PLSS corners and/or offsets shall be surveyed to the Second Order, Class II or better accuracy standards (50 ppm) as specified in the Wisconsin Department of Transportation Guidelines on Standards and Specifications For Global Positioning System (GPS) Surveys in Support of Transportation Improvements Projects (WDOT- GPS Specs.). 2. All PLSS corners and/or offsets must be tied to the Wisconsin High Accuracy Reference Network (WIHARN) that is based on the North American Datum of 1983, 1991 adjustment (NAD83 (91)). Attachment A indicates the location of stations that are part of the WIHARN found in Lincoln County. The County will provide station descriptions and coordinate values to the Contractor. The Order B, Class I and II (1 and 2 ppm) stations were surveyed in cooperation with and according to WDOT specifications on Establishment of a High Accuracy Geodetic Network Using the Global Positioning System (GPS) Technology for Lincoln, Price and Taylor Counties dated 28 March The Contractor shall review the enclosed documents described above to determine if the stations are adequately spaced to provide for proper network geometry relative to the proposed project. If any new Stations need to be established to support this project, the Contractor shall notify the County immediately. 4. Relative positioning using the carrier phase observable is required for establishing coordinates on the PLSS corners. The methodology used by the Contractor shall be included with the Contractor s final report. This should include a discussion on the type of relative positioning technique employed, where it may be acceptable to deviate from the WDOT-GPS Specs, observation times, repeat baselines, types of adjustments, software, number and type of instruments, project time frame, and related information. 3

4 5. The Contractor shall use the WDOT-GPS Specifications as a guideline for data acquisition, analysis and submittal specifications. The County realizes that not all specifications can be met for all PLSS corner locations. In addition, technological changes are occurring that allow for deviation from the Specs. If any of the observations do not meet WDOT-GPS specifications, a systematic approach must be used to determine the certainty of the results (i.e., redundancy, etc.). The Contractor must make a reasonable attempt to acquire data directly on obstructed PLSS Corners using the best available satellite visibility for the day. If through proper data analysis the measurement is deemed to be within the specified classification by the professional doing the analysis, and the situation is documented, the coordinates can be submitted to the County for payment. 6. If the Contractor attempts an observation and/or through professional experience determines that the required data cannot be acquired, two offsets shall be set at a minimum of 300 feet apart. These points should be within direct sight of each other, and if possible, one in direct sight of the PLSS Corner. The Contractor must supply either a 5/8 x 12 re-bar or 1 x 12 iron pipe to set nearly flush for the offsets. If offsets cannot be set within 1000 of the PLSS corner, the County shall be informed before setting the offsets. 7. Offsets must be referenced to two nearby trees or other easily recognizable features. A compass bearing and distance to the nearest foot must be recorded to the references to aid in the recovery of the offsets. A sketch of the surrounding area and brief description of where to locate the offsets shall be prepared. The distance between the offsets must be measured by the Contractor to the nearest 1/100 th of a foot and included in the final adjustments of the GPS data holding to the measured distance between the offsets. 8. The Contractor must include information pertinent to the GPS observation such as station/corner name, description of monument observed, condition of corner, GPS log date, time, and number of satellites on a standard data logging sheet. The Contractor must use the naming convention developed by the County for the Corner name. The County and Contractor will agree upon the forms prior to Project start date. 9. The Contractor shall comply with the data submittal specifications as outlined in the WDOT-GPS Specs. The Contractor must also provide a listing of each corner acquired with coordinate values in Lincoln County coordinates (feet) with standard deviations, ellipsoid height and a brief description of each monument observed. 10. If, in the process of doing this project, the contractor finds an existing monument that appears to be in the wrong location, the Lincoln County Surveyor s office shall be contacted. It shall be the responsibility of the Lincoln County Surveyor s office to correct the error. 11. For PLSS corners that are located off of roads and only accessible by foot, the Contractor shall seek landowner permission if they decide to drive upon private lands to the corner location and will be liable for any damages resulting from entering upon any such lands. The County encourages contacting the landowners before entering private lands. 12. Digging for corners, in roadways, will only occur through direct authorization and coordination of the County Surveyor and the Lincoln County Highway Department. If a corner must be dug, Lincoln County will perform the excavation and pay all expenses incurred. 4

5 13. All services will be performed in strict accordance with the specifications, shall be performed according to surveying practices consistent with the highest professional and technical standards, and all applicable Federal and State laws, rules and regulations. All work must be performed under the direct supervision of a Wisconsin Licensed Land Surveyor. 14. The County requires that all work be completed and that the final report, coordinate tables and maps will be submitted in digital format along with one paper copy to the County no later than: T35N R4 & 5E December 13 th, D. Miscellaneous Provisions 1. No Assignment Assignment by the selected Contractor to a third party of any contract entered into for this project is prohibited and will not be recognized by the County unless approved by the County in writing. 2. Contractor Costs The Contractor s costs shall be submitted on the enclosed cost sheet (Attachment D) for all related expenses to provide the services required. Include a projected schedule when work would be performed. 3. Delays and Extensions After award of the RFP, the time specified shall not be extended because of any delay attributable to the Contractor, but may be extended by the County, at its discretion, in the event of a delay attributable to the County or its authorized representative, or because of unavoidable delays caused by an act of God. Should the Contractor fail to complete the scope of work within the time agreed upon, the County may deduct a sum of $125.00/day from any monies due or that may become due the Contractor for each and every calendar day that the scope of work remains uncompleted. This sum shall be considered and treated not as a penalty, but as a fixed, agreed upon charge for liquidated damages due to the County from the Contractor by reason of inconvenience to the public, delays caused to other projects, and other items that have caused an expenditure of public funds resulting from the Contractor s failure to complete the work. 4. Termination of Contract After award of the RFP, the County may terminate the Contract at any time upon not less than ten (10) calendar day s written notice. In the event the Contract is terminated by the County without fault on the part of the Contractor, the Contractor shall be paid for work or services completed and submitted to the County and meet the standards outlined in this RFP. 5. Indemnification To the fullest extent permitted by law, the Contractor shall indemnify and hold harmless the County and its agents and employees from and against all claims, damages, losses and expenses, including but not limited to attorney fees, arising out of or resulting from the services provided by the Contractor for the requested services addressed in this document. 6. Insurance The selected Contractor shall have adequate insurance coverage that will protect operations conducted under contract, whether performed by the Contractor or anyone employed by them. The Contractor shall be required to furnish the County an 5

6 insurance certificate 5 (five) days prior to contract award, certifying the Contractor is covered by the following types and amounts of coverage: Type Limits Worker s compensation & Employer's Liability Coverage A: $ Statutory; Coverage B: $100,000 Employer s Liability General liability, Bodily injury/personal injury, $1,000,000 each occurrence, Combined single limit Property damage Automobile liability, Bodily injury, Property damage $1,000,000 each occurrence, Combined single limit Umbrella excess liability insurance $1,000,000 each occurrence, Combined single limit 7. Letter of Credit or Bonding The selected Contactor will be required, within seven (7) calendar days of notification of award of the RFP, to post a Performance Bond at least equal to the contract price or an Irrevocable Letter of Credit at least equal to 50% of the contract price and valid for at least 90 days beyond the contract closing as security for the faithful performance of the work to be contracted. 8. Safety All practices, materials, supplies and equipment shall comply with the Federal Occupational Safety and Health Act, as well as any pertinent Federal, State and/or local safety or environmental codes. Work on State, Federal, or Interstate roads must be performed in accordance with the Wisconsin Department of Transportation Permit Form EM (Attachment C). 9. Confidentiality and Rights to Submitted Material All proposals, responses, inquiries, or correspondents relating to or in reference to this request, and all reports, charts, displays, schedules, exhibits, and other documentation submitted by the Respondent shall become the property of the County when received. Any restrictions on the use of data contained within a proposal must be clearly stated in the proposal itself, otherwise, non-disclosure cannot be guaranteed after the selection stage of this procurement due to Wisconsin open records law considerations. 10. Ownership of Contract Materials All materials developed, prepared, completed, or acquired by the contractor during the performance of services specified in this request, including all finished or unfinished documents, digital data, drawings, maps, calculations, reports, ect., shall become the property of the County and shall be delivered to the County at its request during the contract period or at any other time unless other arrangements are agreed upon by the County in writing. Such materials shall not be released or made available by the Contractor to any third party or used for any other project at any time without the written approval of the County. No drawings, maps, documents, reports or other data prepared or completed during the performance of requested services specified in this document shall be copyrighted by the Contractor. 11. Request for Information Any requests for clarification or additional information deemed necessary by any respondent to present a proper proposal must be submitted to the Lincoln County Surveyor via by 4:30 PM CDT, October 12 th, All requests received prior to the above stated deadline will be responded to via by the County in the form of an addendum addressed to all prospective respondents. 6

7 E. Submission of Proposal 1. The Contractor shall submit one signed original and one copy of the proposal sealed and clearly marked with the name of the firm and contact person, on the outside of the envelope by 4:00 PM CDT, October 27th, 2011, to the following address: RFP-Remonumentation Services C/O Tony Dallman Land Information & Conservation Department 801 N Sales St. Suite 105 Merrill, WI The proposal shall consist of all information requested of this RFP, and all other relevant information the Contractor feels is pertinent to the project including: a. A letter of transmittal that bears the signature of an authorized representative of the Contractor and designate the individuals authorized to sign an agreement with the County on behalf of the Contractor. b. One signed and dated copy of this RFP. c. A completed cost estimate sheet (Attachment D). d. Three references from similar remonumentation projects carried out recently. e. Professional biographies of personnel expected to be assigned to the project. f. The number and type of GPS receivers expected to be used for this project. g. A brief but concise description of the field methods intended for data acquisition and data analysis, anticipated observation times, software, projected time frame, and other related information. 3. Proposals received after the date and time of closing will not be accepted or considered and shall be returned unopened, provided that the respondent is identified on the proposal envelope. 4. All information must be legible. The RFP and contents of the proposal submitted by the successful respondent to this Request for Proposal will become a part of any contract award. 5. Facsimiles or electronic transmittals of proposals will not be accepted under any circumstances. 6. All proposals submitted will be binding for a period of 120 calendar days following the proposal opening date unless respondents, upon request of the County, agree to an extension. 7. All proposals submitted will be opened publicly at 4:15 PM CDT, October 27 th, 2011 at the Lincoln County Land Information and Conservation Department. The proposals will be evaluated by Lincoln County staff based upon completeness of proposal, technical qualifications and proposed project costs. Technical qualifications may include but are not limited to quality of professional people assigned to the project, past performance in providing similar services, project references, etc. 8. Lincoln County will select a respondent based upon the recommendation of the staff involved in the proposal reviews. The Land Information, Conservation and University Extension Committee will have the final review and approval of the selected respondent. The award resulting from this RFP will be made to the respondent that submits the response that, in the county s opinion best serves the overall interests of the County. Lincoln County will negotiate a professional services agreement with the successful Respondent. 7

8 F. Rights Reserved This solicitation may be canceled and Lincoln County reserves the right to accept or reject any or all proposals in part or in total, as deemed to be the best interest of Lincoln County. Lincoln County also reserves the right to waive any minor informality or irregularity in any proposal. The RFP does not commit the County to award a contract. It shall be unethical for any person to offer, give, or agree to give any elected official, employee, or former employee to solicit, demand, accept or agree to accept from another person, a gratuity or an offer of employment in connection with any decision, approval, disapproval, recommendation, preparation of any part of a program requirement, a purchase request, influencing the contents of any specification or procurement standards, rendering any advice, investigation, auditing, or in any other advisory capacity in any proceedings or application request for ruling, determination, claim or controversy or other particular matter, pertaining to any program requirement or a contract or subcontract, or to any solicitation or proposal therefore. 8

9 Attachment A 9

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11 Attachment C 11

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15 Attachment D Request for Proposal (RFP) On the remonumentation of PLSS corners using GPS Methods for Lincoln County Contact: Lincoln County Land Information & Conservation Department Tony Dallman 801 N Sales St. Suite 105 Merrill, WI Phone: , Fax: tdallman@co.lincoln.wi.us ContractorName: Address: Phone and Fax Contact Person: Location of Work: Township 35 North, Range 4 East (Town of Somo) and Township 35 North, Range 5 East (Town of Wilson), Lincoln County, WI Completion Date: Final Report Due T35N R4 & 5E December 13 th, Deliverables: See Section A-5 Costs for final report, maps and digital data must be incorporated in the proposed cost listed below. Proposed Costs: Recovery of PLSS corner: $ per corner* (found corners) Reestablishment of PLSS corner: (lost and/or obliterated corners) Coordinates only: (PLSS Corner of record) Town/Landowner Meetings: $ per corner* $ per corner $ per meeting Payment: Payment will be made only for those corners in which resulted in the contractor obtaining a positional value on the corner according to the contracted accuracy standards. Payment schedule will be negotiated upon contract award. * Cost is to include U.S. Public Land Survey Monument Record. The Contractor shall sign the certification below and submit it with their proposal. I certify that I have reviewed the RFP/Memo, the proposed contract language and all associated exhibits and understand the scope of work to be completed and that I am authorized by my firm to submit the costs listed in our proposal. Signature Date 15

16 Attachment E Wisconsin Department of Transportation Guidelines on Standards and Specifications For Real-Time Kinematic (RTK) Global Positioning System (GPS) Surveys in Support of Transportation Improvement Projects 04 December 2002 For Further Information Contact: Wisconsin Department of Transportation Surveying & Mapping Section Geodetic Surveys Unit - Rm 5B 4802 Sheboygan Avenue P.O. Box 7916 Madison, WI (608) Disclaimer The distribution and use of this document does not constitute, in any way, an endorsement by the Wisconsin Department of Transportation. The distribution and use of this document is intended only for the purpose of providing the user, guidelines for planning and execution of real-time surveys relative to a geodetic network using RTK GPS technology. Contact the authorizing agency for instruction when guidelines cannot be met. 16

17 Table of Contents 1. Purpose References Applicability Reconnaissance Standards Data Acquisition, Analysis, and Submittal Specifications... 5 Table 1 - RTK Surveying Guidelines for Establishing New Survey Stations... 6 Explanation of Table 1 RTK Surveying Guidelines... 8 Guideline: 1. Accuracy... 8 Table 2 Sample Analysis of Accuracy Obtained... 8 Guideline: 2. Initialization... 9 Guideline: 3. System defaults... 9 Guideline: 4. Free of Obstructions Figure 1 Sample Plot of Obstructions Guideline: 5. Establish a check point in an area with obstructions Figure 2 Sample Establishment of a Check Point Guideline: 6. Independent Occupations per Station Guideline: 7. Observations at Rover Figure 3 Sample Visibility Diagram of Obstructions at Rover Guideline: 8. Distance Between Stations Guideline: 9. Equipment Checks/Calibrations Guideline: 10. Location of Known Control stations: Figure 4 Sample Location of Four Known Control Figure 5 Sample Location of Three Known Control Guideline: 11. Report

18 Appendix 1 - Two-Dimensional Positioning from Geodetic Control Stations Figure 6 Sample Two-Dimensional Positioning from Geodetic Control Stations Appendix 2 - Three-Dimensional Positioning from Three-Dimensional Control Stations Figure 7 Sample Three-Dimensional Positioning from Three-Dimensional Control Stations Appendix 3 - Three-Dimensional Positioning from Three-Dimensional Control Stations and Vertical Control Stations Figure 8 Sample Three-Dimensional Positioning from Three-Dimensional Control Stations and Vertical Control Stations Appendix 4 - Field Calibration (Scale and Rotation) Figure 9 Sample Field Calibration

19 Purpose This document provides technical standards, specifications, guidelines, and quality control criteria for performing Global Positioning System (GPS) Real-Time Kinematic (RTK) surveys in support of photogrammetric mapping and engineering activities. References Applicability Challstrom, C. W., 1991: Federal Geodetic Control Classification Standards Revision for Network Upgrades, GIS/LIS Hartzheim, P., Fosburgh, B., 1994: Densification of High Accuracy Reference Networks (HARNs), Point of Beginning (POB), Volume 20, Number 2. Hartzheim, P., Henkel, D., (Wisconsin Department of Transportation), 1998: Analysis of Real-Time Kinematic and Fast Static/Kinematic Least-Squares Derived Coordinates Using a Wisconsin County UDN, Trimble Users Conference, San Jose, CA. Hoyle, D., 1992: Unpublished Correspondence, St. Paul, MN. Hull, W. V., (Federal Geodetic Control Subcommittee), 1988, (Reprinted 1989): Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques, National Geodetic Information Center, NOAA, Silver Spring, MD. Wisconsin Department of Transportation, 1992: Request For Proposal on Establishment of a High Precision Geodetic Network Using GPS Technology for Dodge, Jefferson, and Rock Counties, WI, Madison, WI. Wisconsin Department of Transportation, 1996: Guidelines on Standards and Specifications For Global Positioning System (GPS) Surveys in Support of Transportation Improvement Projects, Madison, WI. This document applies to all bureaus, districts, and consultants performing surveys with GPS in support of Department geodetic, engineering, and photogrammetric mapping activities. Determining the practicality of RTK surveying methods can be made based on the following questions: What is the application? What is the desired or required accuracy? What are the alternative positioning methods or guidelines? These specifications are intended for kinematic relative positioning techniques. Different GPS survey techniques (e.g., static, rapid/fast static, etc.) should utilize other specifications (see Reference 2.7). Specifically, each technique is described as follows: 3

20 Kinematic Relative Positioning Technique This technique is applicable for second- and third-orders of accuracy. Consists of one or more receivers remaining stationary and one or more receivers roving during the observation period. Requires lock on a minimum of five satellites. Depending on the GPS receiver hardware, firmware, and software, loss of lock can be tolerated since this technique is capable of determining the integer ambiguities instantaneously. Occupation time at remote station(s) is generally a few seconds to a few minutes. Generally is effective for areas with no visual obstructions projecting more than 15 degrees above the horizon. Rapid/Fast Static Relative Positioning Technique This technique is applicable for first- through third-orders of accuracy. Consists of at least two receivers remaining stationary or one receiver remaining stationary and one (or more) receivers roving during the observation period. Requires simultaneous observation of a minimum of five common satellites at two or more stations to obtain reliable resolution of integer ambiguities. Occupation time at station(s) is dependent on distance between stations, and model of GPS receiver. Occupation times at station(s) may vary between 5 and 30 minutes. Generally is effective for baseline distances less than 25 km. Static Relative Positioning Technique Most reliable of all relative positioning techniques. Using dual-frequency receivers, the technique is applicable for A- through third-orders of accuracy. Using single-frequency receivers, the technique is applicable for first- through third-orders of accuracy. Consists of at least two receivers remaining stationary during the observation period. Requires simultaneous observation of a minimum of four common satellites at two or more stations to obtain reliable resolution of integer ambiguities. Occupation time at station(s) is dependent on distance between stations, ionospheric activity, and model of GPS receiver. An approximate guideline for occupation times for static positioning is approximately 60 minutes for every 10 km of distance separating the stations. 4

21 Reconnaissance A number of factors affect the performance of GPS and the final coordinate position. These factors include the following: Setup errors (pole tips and level/data collector) bracket. Obstructions. Satellite geometry. Observation time. Resolution of correct set of integer ambiguities (initialization). Topography (range of communication link). Weather. Field survey procedures. Quality of control stations. Equipment configuration. Radio frequency interference. Site selection is a key element in reducing the time required for planning GPS surveys and post-processing and analyzing GPS observational data. The following guidelines shall be used for determining the optimal location of newly established survey stations and the potential use of existing stations: At normal antenna height, having a clear view above 15 degrees above the horizon for 360 degrees in azimuth. Where not likely to be disturbed. On stable ground. Readily accessible by vehicle. Avoid tall artificial and natural reflective structure or surfaces that would project above the antenna ground plane. Anticipate future road construction and tree growth. Provide adequate site distances for conventional survey methods. Adhere to airport requirements. Ensure safety of surveyors and others. Avoid radio towers, high transmission lines, and other sources of radio frequency (RF) interference. Off of the traveled portion of a road but within highway right-of-way or other public property (e.g., parks). In the event power lines are not avoidable, place on the opposite side of the road from power lines such that the lines are below 15 degrees above the horizon. Standards Standards are utilized to classify the accuracy of the survey. Standards are driven by the project requirement and not the technology. Positional accuracy for any RTK surveyed station is determined as being relative to the known stations occupied by the base receiver. However, consideration must be given to any and all adjoining stations when accepting these "positional" accuracies because there is no direct observation between adjoining stations (as in conventional surveying). Data Acquisition, Analysis, and Submittal Specifications Specifications are the procedures and processing guidelines that must be followed to satisfy a specific accuracy. Specifications evolve with technology and the development of innovative techniques. Table 1 lists the guidelines for RTK positioning. An explanation of each guideline follows the table. Although not all inclusive, these guidelines provide a consistent policy and serve as a foundation for positioning survey stations. 5

22 Table 1 - RTK Surveying Guidelines for Establishing New Survey Stations (Explanation of Guidelines follows Table 1) Legend: km = kilometers m = meters cm = centimeters NA = Not Applicable sec = seconds Application Guideline Engineering (Project) Control Government and Property Corners Ground Control (Targets) Stakeout Topographic Features 1 Accuracy (95% Confidence Level) 1.1 Horizontal and vertical (cm) Initialization of Rover 2.1 Monitor point quality and RMS to ensure correct initialization. 2.2 Initialize rover receiver in area where at least three quadrants have no obstructions above 15 degrees above the horizon and maintain initialization until point is surveyed. YES YES YES YES YES YES YES YES YES YES 3 System defaults YES YES YES YES YES 4 Base receiver shall be free of obstructions above 15 degrees above the horizon. YES YES YES YES YES 5 Establish a check point in an area with obstructions. NO NO NO YES YES 6 Independent occupations per station 6.1 Minimum number of occupations for new stations. 6.2 Minimum number of measurements per occupation. 6.3 Perform independent known station checks before and after survey. 6.4 Minimum number of known stations used for coordinate solution YES YES YES YES YES

23 Table 1 - RTK Surveying Guidelines for Establishing New Survey Stations (Explanation of Guidelines follows Table 1) Legend: km = kilometers m = meters cm = centimeters NA = Not Applicable sec = seconds Application Guideline Engineering (Project) Control Government and Property Corners Ground Control (Targets) Stakeout Topographic Features 6.5 Horizontal control stations: Minimum number of control stations (latitude, longitude, ellipsoid height) needed to position and check survey. 6.6 Vertical control stations: Minimum number of control stations (orthometric height) needed to position and check survey Observations at the Rover 7.1 Maximum position dilution of precision (PDOP) Number of satellites tracked simultaneously and continuously during entire session 7.3 Obstructions shall be limited to: No obstructions projecting more than 45 degrees above the horizon. Obstructions projecting more than 30 degrees above the horizon occurring in no more than one quadrant. Obstructions projecting no more than 15 degrees above the horizon occurring in no more than two quadrants YES YES YES YES YES 7.4 Minimum observation time (epochs) Collection interval (sec) Distance between stations 8.1 Minimum distance between adjacent stations 400 m NA NA NA NA 7

24 Table 1 - RTK Surveying Guidelines for Establishing New Survey Stations (Explanation of Guidelines follows Table 1) Legend: km = kilometers m = meters cm = centimeters NA = Not Applicable sec = seconds Application Guideline Engineering (Project) Control Government and Property Corners Ground Control (Targets) Stakeout Topographic Features 8.2 Maximum distance between known to unknown stations, known to check stations, and between adjacent stations 8 km 8 km 8 km 8 km 8 km 9 Equipment checks/calibrations WEEKLY WEEKLY WEEKLY WEEKLY WEEKLY 10 Location of known control stations: Number of quadrants relative to the center of the project Report YES YES YES YES YES Explanation of Table 1 RTK Surveying Guidelines Guideline: 1. Accuracy Discussion: The positional accuracy for any RTK surveyed station is determined as being relative to the known stations occupied by the base receiver. Multiple measurements and in some case multiple occupations are taken and averaged. The minimum specified measurements should be within (plus or minus) the desired accuracy of the average value. The desired accuracy is based upon the application of the technology. Engineering (Project) Control refers to the establishment of supplemental control stations for the project. When RTK methods are chosen for data collection and layout, typically sufficient control stations are already in place such as in an area with a county User Densification Network (UDN) or the Height Modernization Project (HMP). Other projects should have control stations established by Static/Fast Static methods prior to RTK work. Government and Property Corners refers to determining the coordinates of section corner and right-of-way monuments. Ground Control (Targets) refers to determining the coordinates of the targets for use on large-scale photogrammetric mapping. Stakeout refers to layout of transportation improvement project features such as the alignment. Topographic Features refers to the data collection of existing site information for use in the design and/or analysis of transportation improvement projects. Example: The intent of this survey is to establish ground control with a positional accuracy of 2.5 cm (0.082 ft) or better. Table 2 shows results. Table 2 Sample Analysis of Accuracy Obtained Point Northing Easting Elevation Height meters feet meters feet meters feet meters feet V = Averaged position

25 Baseline delta North delta East horizontal distance delta Elevation delta Height First occupation, four measurements: W6105-V W6105-V W6105-V W6105-V Second occupation, four measurements: W6107-V W6107-V W6107-V W6107-V Exceeds tolerance. Measure occupation again. Guideline: 2. Initialization Discussion: Initialization shall be performed in an area with obstructions less than 15 degrees above the horizon in at least three quadrants and less than 30 degrees in the fourth quadrant to insure proper integer ambiguity resolution. This initialization must be maintained until after the conclusion of data collection. Scale and rotation (a.k.a., best fit, site calibration, or office calibration) is not necessary when valid control stations are available. If available control stations do not check within allowable base error, contact the authorizing agency for further instruction that may include: Field Calibration (see Appendix 1) Resurvey Other Example: none Guideline: 3. System defaults Discussion: System defaults must remain at manufacturer specified settings to maintain integrity of the data collection. The user may modify settings that are needed to properly collect the data for the specified accuracy (e.g., duplicate point tolerance, units, etc.). Example: none 9

26 Guideline: 4. Free of Obstructions Discussion: The base receiver shall be located in an area with no visual obstructions projecting more than 15 degrees above the horizon. Using GPS in areas free of obstructions will reduce the effects of multipath and aid in the communications between base and rover. When the user encounters an area with obstructions above 15 degrees above the horizon and there are no other options to locate the survey station, session planning shall be used to obtain best satellite coverage outside the obstructed area Example: Figure 1 illustrates day 114, local time, showing five available satellites in view with acceptable PDOP (satellites 7, 8, 11, 28, and 31). Depending upon the application, it may be necessary to reschedule the field operations for a period with six available satellites. Figure 1 Sample Plot of Obstructions Pines Obstruction Satellite available Satellite not available 10

27 Guideline: 5. Establish a check point in an area with obstructions Discussion: A check point must be established for areas of questionable interference (radio or electrical) and/or obstructions. The check point shall be set in an area with no obstructions as described in guideline 4. A check point shall be set prior to entering the hostile area. A check point should be established to the accuracy requirement for engineering (project) control. The user shall maintain lock as measurements are taken and then return to check point to verify the position. A check point may be used to verify initialization of the system. If the system does lose lock, it is recommended to check the newly positioned points with conventional methods. Areas that can only be measured with conventional means shall have a minimum of two check points established. Example: Figure 2 illustrates the location of a check point in relation to overhead utility lines and trees. One check point used to verify the coordinates of points to be positioned. Two check points used to set up total station and establish coordinates of the points to be positioned. The check points may used to measure distances and compute inverses to compare distances between points. Figure 2 Sample Establishment of a Check Point Point to be positioned Check point (optional) Check point 11

28 Guideline: 6. Independent Occupations per Station Discussion: A minimum of two known stations (B-order, Class III or better (see Reference 2.7)) shall be occupied with the rover (as a check) one before and one after each session. The base station shall be different for each independent occupation. This will insure continuity of all the measurements taken during the session from each base setup. If three-dimensional observations are performed, bench marks used for vertical control as known station occupations shall have orthometric heights (NAVD 88 vertical datum) established by differential leveling methods or the Wisconsin Height Modernization Project. Orthometric heights obtained by applying a geoid model height to the ellipsoid height are not acceptable. Example: This procedure describes the steps for using geodetic control stations (see also Appendix 1, Figure 6) or three-dimensional control stations (see also Appendix 2, Figure 7). See Appendix 3 for steps to use geodetic control stations and vertical control stations to position three-dimensional unknown points. See Appendix 4 for steps to perform a field calibration. 1. Set up base receiver on control station A Check control station C with rover receiver (the difference between known coordinates and observed coordinates should be within the allowable base error of the control station (see Reference 2.7)). Record the position and show the differences in all positional components If station C does not check, try station D. If station D checks, continue observing unknowns and check station B at the end. Further investigation should document the problem station If station D does not check, station A could be bad. Move base station to station C and check control station B. If station B checks, continue observing unknowns and check station D at the end. Further investigation should be conducted and then documented for the problem station All control problems should be discussed with the authorizing agency for further instruction Observe unknown stations with rover receiver Take four measurements from each base station. After each measurement, rotate the unit (so that the bubble moves with it) 90 degrees to compensate for systematic errors in the pole and level bubble If there is a potential for multipath (tree branches, power pole, etc.) increase observation time (e.g., from 6 epochs up to 60 epochs) Check control station D (located diagonally from station C) with rover receiver. Record the position and show the differences in all positional components. 2. Move base receiver to control station B (located diagonally from original base station) 2.1. Check control station D with rover receiver. Record the position and show the differences in all positional components Observe unknown stations from second base station with rover receiver There shall be a minimum 60 minutes of separation of time between the first and second occupation of an unknown station. If the second occupation is done on a subsequent day, the measurements should be done such that the time of the occupation is a minimum of 60 minutes before or after the original occupation. Note that the constellation shifts back by approximately 4 minutes per day and a survey on a subsequent day should be timed accordingly. Example: A subsequent observation done 2 weeks (14 days) after the first observation should be adjusted by 56 minutes (14 days times 4 minutes plus 60 minutes shift). The constellation on day 1 at 10 a.m. would be approximately the same on day 15 at 9:04 a.m. If the first observation was done at 10 a.m., the subsequent observation should be completed before 8:04 a.m. or started after 10:04 a.m Setting up two base stations simultaneously and recording measurements on the unknown station during the same occupation is not acceptable, because of the need for different satellite constellations during each occupation Record the positions and provide a weighted mean showing differences in all positional components. Each observation is weighted according to its precision value. The better the precision, the more influence the observation has on the mean coordinate values. If the software program used does not do this automatically, the user may document and use a weighting scheme that reflects the quality of the observations. 12

29 2.3. Check control station C upon completion of survey with rover receiver. Record the position and show the differences in all positional components. 13

30 Guideline: 7. Observations at Rover Discussion: GPS observational requirements that are currently used on Fast Static and Kinematic surveys (see Reference 2.7) shall be followed with the exception of the number of satellites. A minimum of five satellites shall be tracked during any occupation unless otherwise specified. The rover unit can only be expected to provide reliable observation data when obstructions projecting more than 15 degrees above the horizon occur in no more than two quadrants, obstructions projecting above 30 degrees occur in no more than one quadrant, and no obstruction projects more than 45 degrees above the horizon. It is recommended that a check point be used in areas that do not meet the criteria. After an acceptable initialization has been acquired, observation times listed shall be the minimum time. Example: Figure 3 illustrates the maximum allowable obstructions while collecting data at the rover. Figure 3 Sample Visibility Diagram of Obstructions at Rover /0 N degrees maximum Trees 15 degrees maximum 270 Pole Bldg degrees maximum

31 Guideline: 8. Distance Between Stations Discussion: To achieve the accuracy of 2 cm at the 95% confidence level, stations shall be located at a minimum spacing as defined in Table 1, 8.1. This spacing would also maintain an acceptable level of accuracy with conventional (relative) positioning accuracy. Maximum spacing is dependent on a number of factors, most notably: Typical maximum radio range is 6 to 8 km; A radio repeater will extend the range of the system, but spacing should be limited to 8 km to minimize errors introduced by ionospheric activity. Example: none Guideline: 9. Equipment Checks/Calibrations Discussion: Equipment calibrations shall be performed at a minimum of once per week and according to manufacturer's specifications. Example: none Guideline: 10. Location of Known Control stations: Discussion: The minimum of three horizontal (or three-dimensional) and minimum of three vertical (if applicable) control stations used to position the unknown points should be located such that one station is located in each quadrant relative to the center of the project. The quadrants may be rotated from true north-south east-west. The control stations should be located outside the project limits. This configuration of control station should appear to box (see dashed line in example) the project. Example: See Figures 4-5 and Appendix

32 Figure 4 Sample Location of Four Known Control Quadrant 4 Quadrant 1 Control Station 4 Control Station 1 Project Area (includes points to be positioned) Control Station 3 Quadrant 3 Quadrant 2 Control Station 2 Figure 5 Sample Location of Three Known Control Quadrant 4 Quadrant 1 Control Station 1 Project Area (includes points to be positioned) Control Station 3 Control Station 2 Quadrant 3 Quadrant 2 16

33 Guideline: 11. Report Discussion: A report shall be supplied. Supporting documentation shall include the following: Station name Geodetic coordinates (latitude, longitude, and ellipsoid height (and orthometric height, if applicable)) Local coordinates (based upon the specified horizontal datum, coordinate system and zone, vertical datum, and units). Baseline name from base station to the unknown station for the occupation Difference in coordinates For stations positioned from two separate control stations or for multiple observations, supporting documentation shall include the following: A report showing the weighted meaned coordinate being within the allowable accuracy of the measured positions. Each observation is weighted according to its precision value. The better the precision, the more influence the observation has on the mean coordinate values. If the software program used does not do this automatically, the user may document and use a weighting scheme that reflects the quality of the observations. A report showing the position closures between computed coordinates and published coordinates shall be supplied for control stations and/or check points used Pass or fail indication Documents shall be provided as a hard copy and digital data and shall be submitted to the Department representative as a bound report and on 3½-inch, highdensity floppy disks, CD or other medium as specified. Example: Available upon request. 17