Abstract:
The surveying industry is a rising at a rapid rate through advancements in technology. Other specific industries such as industrial metrology which were once segregated from surveying are now closely aligned through the form of measurement. The oil and gas industry provides an avenue for both to co-exist given the specifications and tolerances required to undertake highly accurate surveys. Flange surveys require a specialised form of measurement given the intent of the survey is predominantly for design and reverse engineering applications. Current techniques are not familiar in the surveying industry nor the accuracies that can be achieved.
In this study, a Leica AT402 laser tracker is used as a baseline reading to survey two existing flanges and a spool fabrication joining them. Two conventional survey methods will then be surveyed with the results then analysed and compared. The two conventional survey methods will be based on a Leica TS15 total station and a Leica HDS7000 laser scanner. The results will be based on three main components for calculation – Flange centreline coordinates, plane inclination and bolt hole rotation.
The datasets found that the total station performed better than expected with accurate and consistent results compared to the laser scanner readings and ultimately the baseline readings of the laser tracker. The flange centreline coordinate errors for the total station were submillimetre reading 0.69mm and 0.75mm respectively. The plane inclination and bolt hole rotation results were also similar if not more accurate. The laser scanner results varied between 1mm and 3mm with inconsistent results achieved due to a couple of factors mainly contributed to the manipulation of the point cloud when cleaning and trimming. The laser scanner results provide room for further research to investigate more advanced techniques when working with point clouds.Keywords:
Laser tracker
Flange
Laser Scanning
Baseline (sea)
Total station
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The traditional steel structure deformation monitoring generally uses Total Station and GPS to do monitoring quality control, but there are some disadvantages of these methods. Laser radar technology is a new non-contact measurement technology emerged in recent years. It is ideal for installation and slip construction quality monitoring of large-span steel structure. This paper use laser radar technology to monitor large-span steel structure construction, use laser scanner to scan on steel every period of time and collect 3D point cloud data of the feature points after a period of time. Through the comparative analysis of the data and the chart which reflect the amount of deformation of the feature points, it can accurately obtain the result of structural deformation, oblique direction, and the deviation between the actual coordinates and the design coordinates, which provides the most accurate and direct information for the project. Laser radar technology solves the difficult issues such as workload outside the industry and difficulties in visibility of the traditional measurement methods, greatly improves accuracy and efficiency compared to traditional methods, and achieve a high-precision quality control over the construction.
Deformation monitoring
Laser Scanning
Total station
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Citations (8)
Chimney (locomotive)
Data Processing
Laser Scanning
Total station
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Citations (24)
With the rapid development of dynamic surveying technology, the necessity of precision evaluation becomes more and more urgent. It is now still many technical bottlenecks in dynamic surveying technology, there is even no inspection solution available for some equipments in medium and high velocities. In this paper, it proposes a dynamic inspection principle, its design program and the inspection process based on the rotation platform and the photoelectric sensor. Then the sample equipment is accomplished on which many experiments and proving activities are carried out. According to the experiments, the inspection precision for total station dynamic surveying ranges from 0.4mm to 0.6mm under low velocity condition(lower than 3cm/s),while the precision for GPS dynamic surveying is 3mm-10mm under low and medium velocity conditions(lower than 6m/s).
Total station
Photoelectric sensor
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Today's technology is so advanced and has reached a point where current regulations need to be reviewed and new technologies need to be incorporated in legislation. For this to take place in the Terrestrial Laser Scanning (TLS) field we need to provide evidence of proven and verified instrument accuracy. The proven working accuracy other than a specification in a product brochure needs to be documented for TLS's to be adopted in Railway industry that requires accurate data.
The aims of this investigation is to document working accuracies for TLS and determine if the instrument conform with Sydney Trains specification by calibrating a scanner.
The existing Track Control Marks (TCM's) represented by very small Survey Steel Pins (SSP's) installed on the face of steel masts in the rail corridor will also be tested to see if they can be scanned accurately . The scan time to capture a rail track scene will also be compared with survey points measured using current Survey Total Station (STS) methods.
Various custom targets using colour tones and material found in the rail corridor have been constructed and tested for scanning useability. An indoor self calibration room has
been established which included the setup of a ground control traverse. A target network has been designed and seventy targets have been installed and signalised. The
Leica TS15 and TS30 STS, have been used to signalise the seventy targets. The calibration targets are a mix of Faro and Leica black and white checker pattern scanner
specific targets. The targets closest to the floor have had an SSP fitted in the centre of the checker pattern target for testing. The indirect method of TLS self calibration
method was used by the Leica P20 ScanStation and the Faro Focus 3D X330 scanners, to scan all the targets form three scan positions. The distances between all the installed
target have been measured with a tape for independent checks on the final 3D positional coordinates of the targets. The two scanners were setup in the rail corridor and scanned a section of rail track. This section of track was also measured by a STS using current Sydney Trains conventional methods. Existing SSP's fitted with scanner targets were scanned and used for the registration of these two point clouds.
It was found when the STS data compared to the Scanners data, the 3D positional coordinates were within +-2 millimetres. This result verifies that the two TLS's are as
accurate as a STS therefore conform with Sydney Trains specifications and can be used in the rail corridor for survey measurements. The SSP testing was successful. They can be scanned and used in the registration process of a point cloud. The mix use of scanner targets with different manufacturer scanner was also successful. When the measured
data from a section of rail tract was scanned and surveyed conventionally, the data was compared and the data once overlayed were identical. This test also documented the
significant difference in time for completing a survey in the rail corridor using a scanner and STS. The documented ability to measure fast and with verified accuracy using a
TLS from a safe place within the rail corridor without encroaching into the danger zone from a safety perspective this is a significant development.
Laser Scanning
Total station
Traverse
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In United States, there are almost 600,000 highway bridges. The average life time of these bridges is about 70 years. When bridges reach their mid-life, some damages on structures may occur. The prospective causalities for unproductive bridge inspection can cause serious problems. The main purpose of the bridge inspection is to satisfy the public safety in bridge structural capacity and to protect the public investment. All these emphasize the importance of the accurate and reliable geometric information of the bridges. Geometric data, such as maximum span and minimum vertical clearance are the main parameters of bridge inspection process. All these challenges highlight the importance of terrestrial laser scanner for bridge inspection. Laser scanner is a reliable technology for geometric data collection. Although laser scanners enable surveyors to acquire the data in shorter time, data accuracy should be investigated. The main objectives of proposed study are to investigate and evaluate the accuracy of laser scanners for bridge inspection and to determine the reliability of laser scanners data.The objective of the proposed study was to investigate laser scanner data reliability on bridge inspection projects. Based on laser scanner data, specific bridge component dimensions have been measured and a 3D model of the bridge was created.On the field, the laser scanner was set up on four different locations and captured the bridge substructures data. The office work consisted of registering different point clouds from individual scans together into a single coordinate system. By using registered point cloud, a 3D model of the bridge was created. Afterwards, dimensions of substructure components of the bridge were measured and compared with design drawing data. As a result, error ratio of the compared results is mostly under 1% aside from some irregular conditions at the edges. Comparisons showed that the scanned data is reliable in terms of accuracy. Also data acquisition is faster and data density is much higher than other surveying methods.%%%%M.S., Civil Engineering – Drexel University, 2011
Laser Scanning
Bridge (graph theory)
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Citations (10)
Dam deformation surveys are repetitive surveys that must be undertaken periodically on
high risk structures such as large earthfill dams. This dissertation is to examine and test the
ability of the Leica Nova MS50 terrestrial laser scanner (TLS) and utilise these findings to
develop a dam deformation survey procedure that can be amplified by the inclusion of TLS.
The Leica Nova MS50 is an instrument that has only recently come onto the market. It
provides the latest technology by combining a high precision total station technology with
the capability of capturing highly accurate scanned data.
The existing dam deformation survey methods require manually placing survey targets on
predefined stations located across the surveyed surface, placing the surveyor in danger
from slips, trips and falls on often steep and unstable ground. There is an identified need
for an automated remote process to be developed, providing safety for the surveyor whilst
not compromising the survey accuracy.
It will be possible to determine the accuracy of the Leica Nova MS50 and its suitability to be
utilised in dam deformation surveys by developing three separate testing scenarios:
Angle of incidence test – determining the effect the angle of incidence has on a
distance read;
Difference in length detection – examine the accuracy of the instrument and
determine the difference in length measurement capabilities at nominal lengths; and
Laser Dot Size – to examine the size of the measuring laser at nominal lengths.
This dissertation found the Leica Nova MS-50 to be a very accurate and capable machine. It
was determined from the testing conducted that scanning at 1000 hertz for deformation
scanning had to be limited to distances less than 100 metres (m). It was also verified that
survey control pillars would need to be constructed in the most suitable location; ensuring
scanning procedures are conducted from the same location for each epoch.
This dissertation also found, the rabble rock surface that earthfill dam walls are covered by,
creates exaggerated error when scanning due to the uneven surface. Therefore it was
determined this survey method may be best suited to concrete structures are surfaces that
are flat.
Total station
Deformation monitoring
Laser Scanning
Nova (rocket)
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Considering the hidden danger in the finished stopes in underground metal mines in China, a new cavity data acquisition method based on 3D laser scanning technology is proposed in Dahongshan mine district. This technology uses contactless measurement mode, by which not only the geometric parameter of cavity such as length, area, volume, deformation of roof and wall rock can be gained accurately, but also the security and efficiency of cavity data acquisition are greatly raised. It provides relatively reliable datum for the safety evaluation and the control of emptied stopes as well as the design of ore column stopping. There is certain particularity in application method of 3D laser scanning technology for the finished stopes in mine. For the sake of enhancing the precision and reliability of obtained datum, in this paper, based on systematic analysis of measurement errors of CMS, the key systematic errors of side rolling, pitching and orientation were discussed in detail, and the corresponding calibration method was put forward.
Laser Scanning
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Citations (1)
The surveying techniques using LiDAR have been recognised as a platform that is increasingly becoming popular and evolving within the spatial science profession. As survey job sites continue to grow in size and the need for quick collection of data, mobile laser scanning techniques are exponentially growing. This presents a problem in regards to the accuracies that are being achieved and what the data is fit for.
This paper has a particular focus in regards to mobile laser scanning ground control and what level of accuracy can be expected from the level of ground control implemented. A variety of ground control geometries and quantities were developed to be tested against a traditional total station survey. The data points collected in each scenario where directly compared to the same point collected from the total station. The data obtained allowed me to calculate confidence intervals and the accuracy range in which the data should achieve if the experiment were to be replicated. The direct point versus point comparison allowed me to determine which scenario was the closest in accuracy to a total station survey and if there was any scenario which replicated a total station survey.
The project returned results in which can be used to determine what can be expected from mobile laser scanning with a certain level of ground control. The project developed eight different ground control scenarios with varying results. The most dense and accurate scenario from the mobile laser scanning was horizontally 34.5mm from the total station survey position, whilst the scenario with no ground control at all was 59mm from the total station survey. There was very limited movement throughout the scenarios in regards to the vertical accuracy, all returned accuracies within 31.5mm-39mm from the total station survey. It would be recommended to that densifying the control exponentially does not return accuracies which can be treated as a total station survey. The extra time and costs associated with densifying the control far outweighs the accuracies improvements which can be achieved. It should also be highlighted that mobile laser scanning surveys with no ground control produces usable data. Uncontrolled MLS surveys should only be used for surveys where accuracies better than 50mm are not trying to be achieved; the only downfall of uncontrolled MLS surveys is the lack of redundant data for validation.
Overall the results from the project satisfied the aims and objectives of this research project. The results are discussed in much more depth throughout the paper and recommendations and future research prospects have been discussed.
Laser Scanning
Mobile mapping
Position (finance)
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Estimation of product quantity has existed since the earliest stages of construction. Parallel to other activities of construction, quantity estimation has improved with the advancement of technology. This allows for more robust methods of quantifying material. Laser scanning and photogrammetric methods of survey are beginning to supersede the methods of survey to estimate construction materials, being that of data capture via a total station. The major features that make the photogrammetric and laser scanner methods superior are the saturation of data points, the possibility of not having to come into contact with the material being measured and the time saved during field activities. This research aims to develop a method of survey to quantify a fine grained stored material, in an indoor setting, known as cement clinker.
Due to the constraints placed upon the chosen site the two foundational survey methods that were research included laser scanning and photogrammetry. During the research it was found that both photogrammetry and laser scanning were appropriate methods of survey for data capture of undulating ground terrain, however, due to the harsh environment of the chosen site, laser scanning was deemed a more appropriate choice. The major constraints placed upon the development of a methodology included:
• No access to the area being surveyed,
• No control could be positioned within the storage area of the warehouse and
• The only access that allowed for line of sight to the material being measured is approximately 150 millimetres in width.
In order to complete the objectives and aims a purpose built laser scanner will need to be constructed and the results analysed for their accuracy using 3D software packages. The site chosen for the survey was a Cement Australia warehouse in Port Kembla NSW, Australia and is responsible for storing a material known as Portland Cement Clinker. This study found that a method could be developed that would meet the desired accuracy and could be achieved by staying within the bounds of the limitations placed upon the field work. This project could provide the foundation for obtaining volumes/quantities of fine grained materials being stored in an internal setting.
Laser Scanning
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The regular inspection of the crane tracks of storage cranes at the Container Terminal Altenwerder (CTA), Hamburg requires high accuracy of measurements to determine its position. The allowed tolerances are in the range of 10 mm in the XY plane on a track length of 300 m. The traditional semi-automatic surveying methods are slow and require the interruption of the activities in the storage blocks. The research project AeroInspekt proposed a fully automatic measurement of the position of the tracks using UAV-based photogrammetry. In this paper, the results of the test campaign, carried out in June 2020, were presented where different cameras (150 mm and 80 mm telelens) and flight speeds (1.1 m/s and 1.9 m/s) at a 35 m flying height were performed. Furthermore, an automated rail delineation in the derived surface model was developed and evaluated with ground reference measurements. The results show that the required accuracy of the rail position with an RMSE of 3 mm in XY plane and 8 mm in altitude can be achieved with comparatively less disruption of regular block activities.
Position (finance)
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Citations (18)