Journal of Surveying Engineering-asce 

About: Journal of Surveying Engineering-asce is an academic journal published by American Society of Civil Engineers. The journal publishes majorly in the area(s): Global Positioning System & Geodetic datum. It has an ISSN identifier of 0733-9453. Over the lifetime, 855 publications have been published receiving 10944 citations. The journal is also known as: ASCE journal of surveying engineering & Surveying engineering.

Modeling Terrestrial Laser Scanner Data for Precise Structural Deformation Measurement

Abstract: A modeling strategy has been developed that permits coarse-precision terrestrial laser scanner observations to be used to accurately measure vertical deflections of deforming beams. The model is developed from fundamental beam-deflection equations and implemented using a weighted-constraint, least-squares curve-fitting approach. After the solution is computed, a statistical testing procedure is applied to assess the level of contribution of each of the estimated parameters in the model and identify redundant terms for removal. Two terrestrial laser scanners (TLSs) are employed to test the approach by measuring the vertical displacement of beams undergoing controlled loading for which the magnitude of displacements was at the 2–50 mm level. Results demonstrate that the modeled TLS data, when compared to conventional monitoring equipment, such as convergent digital photogrammetry and contact sensors, achieved an accuracy that is up to 20 times higher than the TLS’s coordinate precision, thus underscoring th...

Dynamic Deformation Monitoring of Tall Structure Using GPS Technology

Abstract: Dynamic deformation monitoring of structures such as long bridges, towers, and tall buildings, for the purpose of determining structural vibrations, is now possible using global-positioning-system (GPS) technology. Current non–GPS techniques for measuring structural vibrations (these include vibration measurement with accelerometers, vibration measurement with a laser interferometer, and vibration measurement with an electronic distance measurement instrument) are first briefly outlined, with advantages and disadvantages noted. The specific application, measurement of structural vibrations in the Calgary Tower, Calgary, Alberta, Canada, using GPS receivers in differential mode, is then described. The results show that the Calgary Tower, under wind loading, vibrates with a frequency of about 0.3 Hz in both north-south and east-west directions. The 0.3 Hz vibration frequency measured on the Calgary Tower is within the range of 0.1 Hz to 10Hz expected for structures of this type. When the capability of GPS to monitor structural vibrations is verified by further tests, it could be adopted as a standard technique.

Integrating a Global Positioning System and Accelerometers to Monitor the Deflection of Bridges

Abstract: During the design phase of a bridge, certain characteristics are assumed, such as traffic and wind loading. In reality, however, these characteristics can vary, therefore it is very important that the health of such a structure is monitored to evaluate whether it is holding up to the true loading. Due to the ever-increasing size and cost of these structures, it is vital that any anomalies from the expected deflections are detected as soon as possible, allowing remedial action to be taken, and hence trying to prevent disastrous consequences. The use of a kinematic global positioning system (GPS) now allows subcentimeter accuracy to be achieved at a rate of up to 20 Hz, and at maximum distances from the reference GPS receivers to the bridge receivers of up to 20 km. This makes such a system capable of detecting the deflections of long bridges. In addition, accelerometers have been proven useful for such monitoring, allowing precise readings at rates of up to 1,000 Hz. However, both systems have their limitations. A GPS is limited partly by multipath and cycle slips, relatively low frequency of data, as well as the need to have good satellite coverage, while accelerometers are limited due to the fact that the derivations (velocities, displacements) from the original uncompensated acceleration readings will drift over time. The integration of the two systems, however, results in a hybrid arrangement that helps to eliminate the disadvantages of the two separate units. This paper presents an integrated monitoring system, consisting of Leica CRS1000 series and SR530 dual frequency code/carrier phase GPS receivers and a Kistler triaxial accelerometer. One of the SR530 GPS receivers and the accelerometer are physically integrated, and their data are synchronized. Using spectrum analysis, main natural frequencies of a monitored suspension footbridge are identified from the hybrid system. A simple data processing algorithm is presented, as well as the results from field trials to show the potential applications of such a system.

Error Models and Propagation in Directly Georeferenced Terrestrial Laser Scanner Networks

Abstract: Cultural heritage recording and engineering surveying are prime applications for terrestrial laser scanners (TLSs) because of the high spatial resolution, high accuracy, and fast data capture rates this technology offers. To date, insufficient attention has been given to the many error sources contributing to the uncertainty of scanner datasets. A full error budget for directly georeferenced terrestrial laser scanner networks that considers both relevant error sources fundamental to surveying and those unique to sampled laser scanner systems is derived. In the case of the latter, new probabilistic models are proposed for angular positional uncertainty due to laser beamwidth and centroid-based target pointing. Analysis of a cultural heritage-recording project in Ayutthaya, Thailand, highlights the disparity between “expected” precision and the more realistic precision indicated by the error budget and demonstrates that the beamwidth error can be a significant factor. The causes and effects of several syste...

Continuously Operating Reference Station (CORS): History, Applications, and Future Enhancements

Abstract: The National Oceanic and Atmospheric Administration’s National Geodetic Survey (NGS) manages the National Continuously Operating Reference Station (CORS) system that comprises a network of over 1,350 sites, each containing a geodetic quality Global Navigation Satellite System receiver. This network is currently growing at a rate of about 15 sites per month. NGS collects, processes, and distributes data from these sites in support of high-accuracy three-dimensional positioning activities throughout the United States, its territories, and a few foreign countries. CORS data are also used by geophysicists, meteorologists, atmospheric and ionospheric scientists, and others in support of a wide variety of applications. This paper addresses the history of the CORS network, some of its applications, and plans for enhancing it within the next few years.