Document No. 67/08/15Issue Date 04/2005

OPERATIONAL REQUIREMENTS FOR

STANDARD SURVEY MARK CONTROLREAL-TIMEKINEMATIC (RTK)

GLOBAL POSITIONING SYSTEM (GPS) SURVEYING

This document is owned and controlled by the Survey and Mapping Manager.

The Senior Geodetic Surveyor is the delegated custodian.

All comments for revision should be submitted to the Senior Geodetic Surveyor.

Authorisation

As Executive Director Technology and Environment Main Roads Western Australia, I authorise the issue and use of this standard.

...... ……….………………

EXECUTIVE DIRECTOR TECHNOLOGY AND ENVIRONMENT

Date: _____/ _____/ _____

No controlled copies are issued for this standard.

The latest copy of this standard is located on the Main Roads Internet site.

REVISION STATUS RECORD

Page
No / Latest
Revision
No / Latest
Revision Date / Revision
Description/Reference
1
2
3
4 / 1 / 07.06.04 / Inserted acronym VRS.
5 / 1 / 07.06.04 / Inserted document number 67-08-53.
6 / 1 / 07.06.04 / Inserted in section 5.2.1: “This section is not relevant to VRS users.”
7
8 / 1 / 07.06.04 / Section 5.2.2: Reference to appendix A removed; section cross referencing updated, reference to document 67-08-50 inserted.
9 / 1 / 07.06.04 / Section 5.3:Reference to document 67-08-50 inserted
10 / 1 / 07.06.04 / Section 6.2: Reference to VRS inserted.
11

CONTENTS

1.PURPOSE...... 4

2.SCOPE...... 4

3.REFERENCES...... 4

4.ACRONYMS...... 4

5.SPECIFICATION FOR RTK GPS SURVEYS...... 5

5.1RTK GPS Validation...... 5

5.2Methods of Survey...... 6

5.2.1 Reference receiver and antenna set-up and operation...... 6

5.2.2 Roving receiver and antenna set-up and operation...... 7

5.3Quality Control...... 9

5.4Liaison...... 9

5.SPECIFICATION FOR STANDARD SURVEY MARK CONTROL...... 5

5.1.Class for SSM Control Surveys...... 5

5.2.Allocation of Standard Survey Mark Numbers...... 5

5.3.Placement of Standard Survey Marks...... 5

5.4.Method of Survey...... 6

5.5.Standard Survey Mark Summary Presentation...... 6

5.6.Liaison...... 6

6.DOCUMENTATION...... 10

6.1Reference receiver and antenna...... 10

6.2Roving receiver and antenna...... 10

7.APPENDICES...... 11

Appendix A: Sample RTK GPS base-station log sheet...... 11

1.
1.PURPOSE

The purpose of this document is to specify the operational requirements ofof Real-Time Kinematic (RTK) Global Positioning System (GPS) surveys conducted for Main Roads Western Australia (MRWA)The purpose of this specification is to detail the Main Roads Western Australia requirement for Standard Survey Mark (SSM) Control.

  1. 2.SCOPE

This Standard is issued to all consultants and contractors who propose to use RTK GPS survey methods for work to be submitted to MRWA, unless This specification shall apply for all SSM Control surveys for Main Roads Western Australiaotherwise approved by the Survey and Mapping Manager.

Advice and further information can be obtained by contacting the Senior Geodetic Surveyor of the Road and Traffic Engineering Branch.

  1. 3. REFERENCES

The following documents relate to this Standard:

  • Survey and Mapping Specification 67-08-43, Digital Ground Survey
  • Survey and Mapping Specification 67-08-46, Quality Statement
  • Survey and Mapping Specification 67-08-36, Road Reference Marks
  • Survey and Mapping Specification 67-08-37, Minor Control
  • Real-time Kinematic GPS Work Instruction 67-08-50
  • Real-time Kinematic GPS Validation Procedures 67-08-53
  • Geocentric Datum of Australia Technical Manual
  • ICSM -– Standards and Specifications for Control Surveys version 1.5 20024 (SP1)

Survey and Mapping Specification 23/05/09

  • Featherstone, W.E. and M.P. Stewart (1999) RTK GPS Evaluation, Contract Report to Main Roads Western Australia, Perth, Australia, 50pp.

The Australian Geodetic Datum Technical Manual, Special Publication 10

Survey and Mapping Specification 2300/05/08 Quality Statement

  1. 4. ACRONYMS

The following acronyms used in this document have the specific meanings indicated.:

AHD- Australian Height Datum

AUSGeoid- National geoid model

BM- Benchmark

GDA- Geocentric Datum of Australia

GPS - Global Positioning System

ANS- Australian National Spheroid

ARP- Antenna reference point

DOLA- Department of Land Administration

GMA- Geodetic Model of Australia

ICSM- Inter-governmental Advisory Committee on Surveying and Mapping

MGA- Map Grid of Australia

RM- Reference Mark

RRM- Road Reference Mark

RTK- Real-time kinematic

RINEX- Reciever Independent Exchange format

RM- Reference Mark

SSM- Standard Survey Mark

VRS- Virtual Reference Station

5.
5.SPECIFICATION FOR STANDARD SURVEY CONTROL MARKSRTK GPS SURVEYS

5.1.Class for SSM Control Surveys

The survey of all new Standard Survey Marks (SSMs) for Main Roads Western Australia shall be to DOLA Class A standard (refer to DOLA specification 2000/04/009). The ICSM Standards and Specifications for Control Surveys 1994 (SP1) outlines the requirements of Class and Order (as per the table below).

5.2.Allocation of Standard Survey Mark Numbers

SSM number allocations can be applied for by contacting the Senior Geodetic Surveyor of the Road and Traffic Engineering Branch. The number of new SSMs per 1:250,000 map sheet is to be supplied with your application.

The appropriate number of brass plaques, witness plates and, where required hatch covers, will also be made available on request.

Used, unused and upgraded SSMs must be reported to the Senior Geodetic Surveyor on completion of the job.

5.3.Placement of Standard Survey Marks

The prime considerations when placing new Standard Survey Marks are:

the safety of the surveyor and public,

the mark should be in close proximity to the anticipated work area,

the long term stability and permanence of the mark,

intervisibility to at least one adjacent SSM,

the ideal spacing between adjacent SSMs is 500 m to 5 km,

if GPS is to be used, there should be no significant obstructions intruding into the space formed by a cone 15 above the horizon, (see Appendix A)

avoid placing the mark close to a strong radio transmitter or under high voltage power lines.

The practice of placing the SSM near the road reserve boundary and using an eccentric reference mark in the road formation as the observing and/or intervisibility station, should be avoided at all times on gravel roads and shall only be used on sealed roads if all other options have been exhausted.

All SSMs installed must comply with DOLA specification 2000/04/005. A copy of this specification is to be obtained from the Senior Geodetic Surveyor of the Road and Traffic Engineering Branch.

5.1 RTK GPS Validation

All RTK GPS equipment and software/firmware used for contract surveys to MRWA must first have been tested and validated on the RTK GPS Testing and Benchmarking Facility at Curtin University of Technology using the techniques and software specified in Real-time Kinematic GPS Validation Procedures

67-08-53.

The results of the RTK GPS validation will be used by MRWA to determine the type of surveys that can be conducted for MRWA using that equipment.

This validation is essential for both the RTK GPS equipment and the software/firmware, and holds for all surveys subsequently conducted using only this RTK GPS equipment and software/firmware. The validation is required if the RTK GPS equipment is hired.

If a new set of RTK GPS equipment and software/firmware, or a new version of the software/firmware, is to be used for contract surveys for MRWA, a re-validation must be undertaken. Only the Survey and Mapping Manager can approve exceptions to this requirement (eg. minor changes in a software/firmware upgrade).

Consultants or contractors to MRWA can perform the validation themselves using the techniques and software specified in Real-time Kinematic GPS Validation Procedures. The results of this verification must be included with the contract survey results submitted to MRWA.

Alternatively, independent validation and certification can be performed, on behalf of MRWA, at a cost of $200 per data set by the Departmentof Spatial Sciences at Curtin University of Technology. The data must be delivered in the format specified in Real-time Kinematic GPS Calibration Procedures. If not, an additional fee will be charged at $160 per hour for data reformatting. The consultants at Curtin University of Technology will issue a certificate, which must be included with the contract survey results submitted to MRWA. The consultants at Curtin University of Technology will not conduct the RTK GPS surveys.

Consultants and contractors to MRWA are not to contact Curtin University of Technology regarding the validation or for a copy of the Real-time Kinematic GPS Calibration Procedures. All queries and requests should be directed to the Senior Geodetic Surveyor of the Road and Engineering Traffic Branch.

5.2Methods of Survey

For the purpose of this Standard, two modes of RTK GPS survey are defined.

  1. Fixed-point surveys - coordination of marked points, survey monuments or ground features that can be accurately resurveyed. These marks are permanent or semi-permanent such that they may be resurveyed at some time in the future.
  1. Pick-up surveys – coordination of features that have no monumentation or ground features that cannot be accurately resurveyed. The distinguishing feature of pick-up surveys is that individual points cannot be reoccupied as part of a field-validation procedure.

All coordinates derived from either mode of RTK GPS survey must be computed with respect to geodetic survey control on the appropriate geodetic datums.

An experienced operator must always conduct RTK GPS surveys for MRWA.

5.2.1Reference Receiver and Antenna Set-up and Operation

This section is not relevant to VRS users.

  • Reference GPS receivers and antennae (aka RTK GPS base-stations) must be established such that the roving-to-reference GPS receiver separation will be no greater than 5km (ideally 2km) at any stage of the survey.
  • Reference GPS antennae must be set up over a control point of known quality (either an existing SSM or a new geodetic control station established in accordance with Survey and Mapping Specification 2300/05/06, Minor Control, or Survey and Mapping Specification 2300/05/07, Road Reference Marks).
  • The coordinates of the control point must be known in three dimensions (geodetic latitude, longitude and ellipsoidal height) with respect to the GDA94. If these control coordinates have been transformed from other geodetic datums, the transformation technique and parameters must be specified.
  • The position of any existing control points must be verified by check measurements to RMs before they are adopted and used.
  • The appropriate height of the antenna’s phase centre must be measured, recorded, and input into the reference or roving GPS receiver as required by the RTK GPS equipment and software/firmware being used.
  • There should be no obstructions to the GPS satellite signals intruding into the space formed by a cone of 15-degrees elevation above the horizon of the reference GPS antenna.
  • The site of the reference GPS antenna must be uncontaminated by probable sources of multipath and electrical interference (eg. strong radio transmitters or high-voltage power lines).
  • The reference receiver must be correctly configured to generate and transmit RTK GPS corrections compatible with the roving RTK GPS receiver(s).
  • The GPS data-sampling rate should be as fast as possible (preferably one-second).
  • A standard log sheet (see example in Appendix A) must be completed for each reference station occupation, which includes the following information.
  • Name, identification number and type of control point (eg. SSM, RRM);
  • Receiver make, model and receiver serial number;
  • Antenna make, model and serial number;
  • Firmware/software make and version number;
  • Antenna set-up information (orientation, antenna height measurements [true vertical or slope height], antenna set-up diagram);
  • Start and stop time of the receiver;
  • Approximate sky visibility plot of the reference site;
  • Three-dimensional coordinates of the reference point (including datums), and any transformation methods and parameters used;
  • Any unusual site features (including any possible sources of multipath and electrical interference);
  • Any unusual occurrences during the survey (eg. power failure, inclement weather conditions).

5.2.2Roving Receiver and Antenna Set-up and Operation

  • The roving GPS receiver must be configured with the appropriate height of the roving GPS antenna’s phase centre, which must be updated if the roving GPS antenna height is changed during the survey.
  • The GPS data-sampling rate of the roving GPS receiver should be as fast as possible (preferably one-second) and must be the same as that of the reference GPS receiver.
  • The roving-to-reference GPS receiver separation must be no greater than 5km (ideally 2km) at any stage of the survey. This restriction does NOT apply to VRS users.
  • There should be no significant obstructions to the GPS satellite signals intruding into the space formed by a cone of 15-degrees elevation above the horizon of the roving GPS antenna.
  • The site of the roving GPS antenna must be uncontaminated by probable sources of multipath and electrical interference (eg. strong radio transmitters or high-voltage power lines).
  • Current RTK GPS corrections must be received from the reference receiver or VRS network for each point coordinated and for the entire time that measurements are collected to determine that point’s position.
  • Each site to be coordinated must be occupied for a minimum of five (5) continuous GPS epochs (preferably 20 or more). Importantly, this occupation period must be the same as that used for the RTK GPS equipment and firmware/software validation (Section 5.3)
  • A minimum of five (5) GPS satellites (preferably 6) must be observed for each point coordinated and for the entire time that measurements are collected to determine that point’s position.
  • The Position Dilution of Precision (PDoP) must be less than 6.0 for each point to be coordinated and for the entire time that measurements are collected to determine that point’s position.
  • The roving receiver must indicate that an ambiguity-fixed GPS position solution has been achieved for each point to be coordinated and this must be maintained for the entire time that measurements are collected to determine that point’s position.
  • All other proprietary software/firmware quality indicators must be satisfied for each point to be coordinated and these must be maintained for the entire time that measurements are collected to determine that point’s position.
  • The proprietary quality indicators used must be described in the project report and included with the results submitted (Section 5.3).
  • During each survey, fixed-points (beginning of Section 5.2) must be resurveyed once every 30 minutes. These fixed-points must be at a distance no greater than 1km from the area in which the survey is being conducted. The resurveyed positions must be validated (including documentation and justification) according to one or a combination of the procedures in section 6 of this document.
  • If the resurveyed position disagrees with the previously determined position by more than the positional tolerance set by MRWA, the RTK GPS system must be re-initialised, the fixed-point resurveyed and checked, and all points surveyed since the previous survey of the fixed point must be resurveyed.
  • All horizontal positions must be referenced to the GDA94 (or MGA94). If these coordinates have been transformed, the transformation technique and parameters must be specified.
  • All vertical positions must be referenced to the AHD.
  • The geoid modelling technique(s) used to derive the AHD heights from GPS ellipsoidal heights must be documented and justified according to one or a combination of the procedures in section 7 of MRWA Work Instruction 67-08-50.
  • A standard log sheet (see example in Appendix A) must be provided for each GPS roving receiver, which includes the following information.
  • Receiver make, model and receiver serial number;
  • Antenna make, model and serial number;
  • Firmware/software make and version number;
  • VRS Users only: Name of VRS network provider.
  • Antenna set-up information (antenna height measurements [true vertical or slope height], antenna set-up diagram);
  • Date, Start and stop time of the receiver;
  • Number of satellites, PDoP and number of epochs used for each point surveyed
  • Any unusual site features (including any possible sources of multipath and electrical interference);
  • Any unusual occurrences (including time) during the survey (eg. power failure, loss of radio link, unscheduled re-initialisation, inclement weather conditions).

Where practicable, the GPS antennas should be of the same make and model. If not, the RTK GPS software/firmware must be able to make appropriate corrections for the different phase centres. VRS users must ensure they are using a GPS antenna that is approved by their VRS network provider.

Where practicable, the roving and reference GPS antennae should be oriented in the same direction so that common phase centre variations cancel.

Where practicable, the roving GPS antenna should be stabilised over the unknown point using a bi-pod or tripod.

5.3Quality Control

The burden of proof is on the consultant or contractor to demonstrate to MRWA that quality control criteria listed in Sections 5.2.1 and 5.2.2 have been met for all points, either by direct analysis or unequivocal implication.

Consultants and contractors are referred to RTK GPS Work Instruction 67-08-50 for quality control procedures for RTK GPS surveying.

The consultant or contractor must supply the quality indicators listed in Sections 5.2.1 and 5.2.2 and any other information to allow MRWA to ensure that this Specification has been met.

The survey of all new SSMs is to be completed according to DOLA specifications 2000/04/009. A copy of this specification is to be obtained from the Senior Geodetic Surveyor of the Road and Traffic Engineering Branch.

5.2Standard Survey Mark Summary Preparation

Presentation of SSM summaries is to be completed according to DOLA specification 2000/04/004. A copy of this specification is to be obtained from the Senior Geodetic Surveyor of the Road and Traffic Engineering Branch.

5.4Liaison

Consultants and contractors to MRWA are not to contact Curtin University of Technology regarding these RTK GPS survey specifications.

Main RoadsAll queries and requests should be directed to the Senior Geodetic Surveyor of the Road and Traffic Engineering Branch.

Contact: Geoff Xanthis

(08) 9323-4152 (direct)

(08) 9323-4449 (fax)

6.DOCUMENTATION

All SSM RTK GPS surveys must include the following documentation and be forwarded to the Senior Geodetic Surveyor of the Road and Traffic Engineering Branch for audit and review prior to registration with DOLA.