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Mainroads WA through both its inhouse survey capacity and survey suppliers, undertakes a variety of surveys that have varying degrees of accuracy requirements. It is the responsibility of the Consulting Surveyors to use and determine instrumentation relevant to the accuracies required for their surveys. It is therefore the responsibility of the Consulting Surveyor to ensure that the survey instrument being used to perform the work is in working order and within its specified calibration ranges.
This guide for Mainroads WA survey equipment custodians, provides examples of typical modern Instrument Specifications which could be used as a basis for contract audit, checking or preparation. The use of instrumentation appropriate to the task is an important contract function that should be monitored by Mainroads Project Managers.
The procurement,registration,maintenance and disposal of survey instrumentation for Mainroads is the responsibility of the asset custodian in their respective Region.
The Surveying and Geospatial Services branch will continue to provide technical advice and support to the organisation in regards to instrument calibration and testing, purchase and loan requirements, and storage and handling responsibilities.
Refer to Surveying and Geospatial Services 67-08-43 "Digital Ground Survey" for the class of survey accuracy requirements and also 67-08-107 being the "Guideline for Settlement Monitoring Surveys" for accuracies and minimum Instrument capabilities required to achieve the survey outcomes.
It is the responsibility of the Senior Engineering Surveyor to register and maintain details for the following survey instruments and equipment as part of the Fixed Asset System for the Surveying and Geospatial Services Branch:
The Fixed Asset records should include the following details:
Additional records to be maintained on file for each respective instrument should include any service details and Calibration data where appropriate and include:
Minor survey equipment (
It is the task of each Responsibility Area to allocate an officer to manage Survey instruments within their Region.
It is the responsibility of the Senior Engineering Surveyor to maintain calibration records for the following survey instruments and equipment for the Surveying and Geospatial Services Branch (see above).
The nominated Asset Manager will monitor all arrangements for the instruments and equipment that are to be calibrated or tested in their respective fixed asset organisation.
The calibration, testing and adjustment of the survey instruments should be undertaken by Mainroads Surveying and Geospatial Services staff, a third party certified survey company or a licensed distributor, details of whom are available from the Senior Engineering Surveyor.
Refer to Appendix A for a summary of typical testing and adjustment procedures, which is relevant to this Guideline.
As a guide, the schedule below illustrates the frequency that instrument calibration, testing and adjustment should occur.
Type of Instrument
Calibration andTesting Periods
Location of Calibrationor Test
The disposal of all major survey instruments and equipment is the responsibility of the asset custodian in each respective fixed asset organisational structure. The Senior Engineering Surveyor is available to provide assistance in regards to organising instrument appraisals.
This instrument would be used for high accuracy surveys such as Bridge Construction or Monitoring and may have refletorless capabilities built in. The instrument could also be used for Digital Ground Surveys.
Positioning Accuracy Rotation Speed
This Instrument would be used for high accuracy surveys such as Bridge Construction or Monitoring and may have reflectorless capabilities built in.The instrument could also be used for Digital Ground Surveys.
1. Direct from Total Station via RS232C or Bluetooth interface.
2. Stand-alone 'Card to PC' interface module.
These levels would typically be used for minor works and 3rd Order levelling.
These levels would typically be used for minor works and 4th Order levelling.
Typically used for Road Reference Mark surveys.
Typically used for control surveys requiring mm accuracy
These units are kept and maintained by the Surveying and Geospatial Services branch.They are expensive units requiring specialist skills to operate and process data. These units may be used for control densification in Static mode or full detail pickup(except hard surfaces) in RTK mode.
The following specifications are typical:
Static and Fast Static surveying precisions:
Horizontal: +/- 5mm + 0.5 ppmVertical : +/- 5mm + 1 ppm
Kinematic surveying precisions:
Horizontal : +/- 10mm + 1ppmVertical : +/- 20mm + 1ppmInitialisation time : typically 10 seconds
Weight : - approx 1.4kg GPS unit only - approx 3.7kg unit with pole,battery,data recorder
Operating temperature: - 40deg to + 65 deg.Water/dustproof : IP 67 standard dustproof:temporary immersion to 1 metreShock/vibration : withstand a 2 metre pole drop onto concrete
Electrical: : 11 to 28V DC : Rechargeable,removeable lithium ion battery
Communications and data storage
There are numerous types of handheld units within Mainroads WA but typicallyThey may conform to the following.
TribrachTribrach to prism adapter
Tribrach plusTribrach to prism adapte
Tripod Timber, telescopic flat head. Extended Length 1.7m.
Tripod Timber, telescopic flat head. Extended Length 1.7m.
Staff Aluminium, Australian metric 0.5cm face, 5m, 4 piece telescopic.
Tripod Aluminium, heavy duty, telescopic flat head. Extended Length 1.7m.
Staff Aluminium, metric 1 cm E face, 5m, 4 piece telescopic.
The following documents relate to this Guideline: Surveying and Geospatial Services Standard 67-08-43 "Digital Ground Survey"Surveying and Geospatial Services Guideline 67-08-107 "Settlement Monitoring Surveys"
The following is provided as information only and is a suggested methodology for the testing and adjustment of standard survey instrumentation.
1.0 Testing and adjustment of Optical Theodolites, Electronic Theodolites and Total Stations
The following procedure shall be undertaken for the testing of horizontal and vertical collimation in Optical Theodolites, Electronic Theodolites and Total Stations.
These procedures shall be read in conjunction with the handbook for the instrument as the testing procedure and adjustment does vary between different makes and types of instruments such as optical or electronic.
When an instrument is to be tested and if necessary adjusted it should be set up on firm ground and the tripod should form a stable support.
1.1 Horizontal Plate Bubble Adjustment
Repeat the procedure to check the adjustment is applied correctly. 1.2 Adjustment of the Cross-Hairs
As the horizontal and vertical adjustments are linked, they should be carried out jointly and both conditions satisfied before proceeding to adjustment 1.3
1.2.1 Adjustment for Horizontal Collimation
If the readings are identical the instrument is in adjustment. If not the instrument should be adjusted so the line of sight is moved ¼ of the distance towards the first reading.
Repeat the procedure to check the adjustment is applied correctly.
1.2.2 Adjustment for Vertical Collimation
Repeat the procedure 1.2.1 and 1.2.2 to check the adjustments have been applied correctly.
1.3 Horizontal Axis Adjustment
If the two marks at B coincide the instrument is in adjustment.
1.4 Vertical Circle Index Adjustment
If the marks (or the readings) coincide the instrument is in correct adjustment, otherwise :
1.5 Adjustment Screws
Ensure when adjusting an instrument that the last movement of the adjustment screw is clockwise (tightening) to prevent the instrument falling out of adjustment.
1.6 Recording of Tests
All tests for the adjustment of optical theodolites, electronic theodolites and total stations shall be recorded in a Survey Equipment Field Test Record sheet and filed with the equipment records.
2.0 Testing and Adjustment of Survey Levels
Survey levels can be tested and adjusted using the procedure known as the ' Two Peg Test'.
2.1. Set-up One
Set the instrument up midway between 2 pegs A and B, 60 metres apart on fairly level ground. Level the instrument and read the staves at pegs A and B (a1 and b1). This will give the true difference in height, Δ H, between pegs A and B. In Figure 1 below, the line of collimation is inclined downwards by an angle causing the staff reading at A to be in error by an amount e. Note that because peg B is exactly the same distance from the instrument as peg A the same error e occurs. This same error e is applied to each staff reading and thus the true difference in height can be found.
Note: This difference may have been determined from previous tests on two fixed points. In the case where the true height difference is known this step may be omitted. Fixed points shall be tested and results recorded at least once every six months
2.2. Set-up Two
Set up approximately 2 metres behind the staff at A, in position 2. Centre the circular bubble and record the staff readings a2. Apply the difference in height, Δ H, to reading a2 to predetermine the reading b2. Read the staff at position B, as shown in figure 2 below, compare the two values.
2.3 Adjustment If the actual reading differs from the pre-determined value b2 by more than 2mm, then the level should be adjusted using the adjustment screws on the eyepiece of the instrument and in accordance with the handbook for the instrument. Ensure the last movement of the adjustment screw is clockwise (tightening) to prevent the instrument from falling out of adjustment.
Always repeat the procedure to ensure the instrument is now in adjustment.
2.4 Example of a Two Peg Test
After readings are taken at the 2nd position, the difference = 0.691 (2.833 - 2.142), instead of 0.705 (2.074 - 1.369) as at the 1st position. Thus the level has an error of 0.705 - .691 = 0.014.
The correct reading at B should be 2.847 (2.142 + .705); the level is adjusted to this reading using the adjustment screws on the eyepiece of the instrument and in accordance with the handbook for the instrument. For this example, the following would be entered in a Level Calibration Field Record Sheet . (the tabulation includes a recheck)
3.0 Calibrated Survey Measuring Band
Calibrated measuring bands in continuous use should be calibrated annually. Calibrated measuring bands used only for standardisation of measuring equipment should be calibrated every five years. The calibration shall be performed under Landgate supervision, using an approved procedure and certified as to its accuracy.
The original of the calibration certificate shall be filed with the equipment records, and a copy issued with the calibrated measuring band.
4.0 Differential Levelling Staves
Annual calibration of all differential levelling staves is recommended. The calibration is to be performed on the Landgate Test site in Boya , using an approved procedure.
The calibration certificate shall be placed on the equipment file and a copy issued with the staves.
4.2 Calibration Factors
Staff calibration factors can be obtained from the latest calibration certificate attached to the differential staves.These are used to provide final adjusted levels in a levelling traverse when completing a level abstract form. If there is a large height difference along the traverse then the Calibration factor will make a significant difference in the final adjustment.
5.0 Tribrachs and Optical Plummets
5.1 Field Testing Method
Repeat the procedure to check the adjustment is applied correctly. For tribrachs or optical plummets that can be rotated an alternative method can be used by rotating the mechanism through 60 degrees and plotting the circle of error. The error can be then removed by moving the cross-hairs using the adjustment screws.
6.0 Levelling Staves
These are to be tested by a visual inspection of the staff face, condition of the foot and joints and measuring with a five metre steel tape, which has been tested against a calibrated survey measuring band.
A comparison of staff graduations against equivalent marks on the steel tape shall be made over the entire length of the staff.
Should any reading disagree by more than 2 millimetres for a 5 mm staff face or 4 mm for a 10 mm staff face, the staff shall be not be used and clearly marked as such.
7.0 Poles, Survey Bands, and Tapes
All Poles, Survey Bands and Tapes shall be tested by a visual inspection for condition of the item and by measuring against a calibrated baseline or a calibrated survey measuring band.
All Poles, Survey Bands and Steel Tapes shall not be used if any graduation is in error by 5 millimetres or more.
Poles should be straight and the level bubble checked regularly for adjustment (by using a detachable staff bubble)
All fibreglass or cloth Tapes shall not be used if any graduation is in error by 50 millimetres or more.
8.0 Measuring Wheel
Measuring wheels shall be tested by a visual inspection for the condition of the item and by measurement against a calibrated baseline or calibrated survey band. Measuring wheels shall not be used if the measured distance is +0.1 metres over 50 metres.
9.0 GPS/GNSS Systems
The Curtin University GPS/GNSS testing pillar network should be used together with thier recommended observation and data processing techniques. In this way, results for baselines observed can be compared to those of the network to ensure that the GPS/GNSS receiver used is performing to the manufacturer's specifications and that the processing software used produces the desired outputs for analysis.