Search

The purpose of this study was to investigate the effect of augmented reality (AR) using a 3D app in a smartphone on students' learning outcomes and satisfaction in teaching angle measurement error to vocational high school students with different spatial ability. A quasi-experimental pretest/posttest was employed. There were 197 students from three vocational high schools in the southern, northern, and eastern part of Taiwan participated in this study. To minimize the biased result, we established one control group and one experimental group in each school. The experimental group used multimedia teaching tools and AR technology as a supplement, while the control group was taught by multimedia teaching tools only. We assessed some factors that possibly affect the learning outcomes and learning satisfaction, including different spatial abilities and different digital materials as teaching tools. Our finding highlights that different teaching materials influence students' learning outcomes and satisfaction, whereas spatial ability does not affect. Further discussion and implementation are also identified in this study. [ABSTRACT FROM AUTHOR]

Christopher Hansteen, professor of applied mathematics at the University of Oslo, was appointed as a part-time director of geodesy at the Geographical Survey of Norway in 1817. He quickly realized that previous measurements of angles using geographical circles did not produce data of required quality for geodetic surveying. Using archival sources, the article describes how Hansteen acquired a theodolite from Germany and applied it to demonstrate to the National Assembly (Storting) that investment in new instruments for the Survey was required. With funds granted in 1824, he ordered theodolites, sextants and chronometers from German instrument makers. He conducted a field operation in 1827 in preparation for a first-time survey and mapping of the entire coast of Northern Norway. The article draws on observation logbooks to reconstruct the triangle arc established with the new theodolites between 1828 and 1842. The triangulation stations served as reference points for plane table mapping. Map orientation and geodetic coordinates were controlled by astronomical observations of latitude and chronometer determinations of longitude at two temporary observatories and through selected field observations. The resulting ten maps were the first production released to the public by the Geographical Survey of Norway. [ABSTRACT FROM AUTHOR]

Abstract The vehicle theodolite has been the trend of the optical shooting range survey. While tracking and imaging of the long-distance dim targets have not been solved perfectly in this field, so this paper presents one active polarization imaging technology to find a way to deal with it. Firstly, we put forward a new active polarization imaging system with the lighting mode of circularly polarized laser and receives the reflected light by the mode of range-gating technique; secondly, deduces the pulse laser beam pointing algorithm; thirdly, describes the extended Kalman filtering algorithm to compensate the delay in the process and the calculation of the polarization angle, the attitude angle of flight target using single station cosine method and the depolarization of the circularly polarized laser. Finally, the result of this active polarization imaging technology which is simulated and analyzed in Simulink shows that the pointing precision can reach 0.0075 degrees. Then the analysis in this paper provide a theoretical basis for the application of the active polarization imaging technology in the field of the optical shooting range survey. [ABSTRACT FROM AUTHOR]

Animal‐attached technologies can be powerful means to quantify space use and behavior; however, there are also ethical implications associated with capturing and instrumenting animals. Furthermore, tagging approaches are not necessarily well‐suited for examining the movements of multiple individuals within specific, local areas of interest. Here, we assess a method of quantifying animal space use based on a modified theodolite with an inbuilt laser rangefinder. Using a database of >4200 tracks of migrating birds, we show that detection distance increases with bird body mass (range 5 g to >10 kg). The maximum distance recorded to a bird was 5500 m and measurement error was ≤5 m for targets within this distance range: a level comparable to methods such as GPS tagging. We go on to present a case study where this method was used to assess habitat selection in seabirds operating in dynamic coastal waters close to a tidal turbine. Combining positional data with outputs from a hydrographic model revealed that great cormorants (Phalacrocorax carbo) appeared to be highly selective of current characteristics in space and time, exploiting areas where mean current speeds were <0.8 m·s−1 and diving at times when turbulent energy levels were low. These birds also oriented into tidal currents during dives. Taken together, this suggests that collision risks are low for cormorants at this site, as the 2 conditions avoided by cormorants (high mean current speeds and turbulence levels) are associated with operational tidal turbines. Overall, we suggest that this modified theodolite system is well‐suited to the quantification of movement in small areas associated with particular development strategies, including sustainable energy devices. [ABSTRACT FROM AUTHOR]

Abstract Aiming at the shortcomings of calibrating the screen plane equation by using traditional double theodolite intersection method, the optimization program of accurately calibrating the screen plane equation of the sky screen vertical target is proposed. The LED surface light source without off-axis phenomenon is designed as projection light source of light screen. The position and attitude of the reference ruler of the double theodolite measurement system are optimized. The technology of thickness center recognition of light screen are studied, which is designed a special light screen receiver with the functions of translation, rotation, lifting, fine adjustment, image capture and processing. The accurate calibration experiment of the screen plane equation of the sky screen vertical target has been completed. The feasibility and rationality of this scheme are verified through live fire experiments. Compared with the traditional double theodolite calibration method, the coordinate accuracy of the optimized calibration method is improved from 4 mm to 3 mm in an effective target surface of 1 m × 1 m. [ABSTRACT FROM AUTHOR]

In the early 1970s. Roger Payne and colleagues developed a non-invasive, shore-based method for collecting data on free-ranging marine mammals in their natural environments. By using a theodolite, or surveyor's transit, they were able to collect data on nearshore marine mammal movement patterns, habitat use, and behavior without any disruption to the animals. As technology advanced, theodolite data collection progressed from analog machines requiring manual data entry to digital equipment linked to computer software that facilitated data management and automated calculations of marine mammal positional information. There are limitations associated with theodolite use, and concurrent data collection methods can contribute information that may not be possible with shore-based research alone. Since the first published research in 1978 using a theodolite to describe the behavioral ecology of dolphins off Argentina, at least 46 species of marine mammals in 36 countries have been tracked by theodolite, and the method continues to be used globally to contribute to non-invasive marine mammal research, conservation, and management. [ABSTRACT FROM AUTHOR]

The article discusses the use of underwater passive acoustic monitoring (PAM) and theodolite tracking to study Indo-Pacific humpback dolphin behavior and sound production. The PAM and shore-based theodolite tracking findings are compared. It is noted that three Ecological Acoustic Recorders (EARs) were deployed on the monitoring site of Lung Kwu Tan (LKT).

Warfare is often considered as a key factor in the formation complex societies, but in the Pacific archaeological evidence for inter-group conflict during political centralization is rare. Most earthwork forts in Tonga are assumed to have been built in the nineteenth century when the traditional system of rulership collapsed, yet few forts on Tongatapu have been excavated or 14C dated. A fort in the chiefly center of the ancient Tongan state was mapped with theodolite and LiDAR, and excavated. Radiocarbon and traditional history indicate the fort known as the Lapaha Kolotau was made in the fourteenth century AD at the same time that chiefly architecture was being built at an unprecedented scale at the new elite center. The construction of an earthwork fort provides the first evidence that political centralization in Tonga was likely to have been contested. [ABSTRACT FROM AUTHOR]

Absolute geomagnetic measurement is very important work in geomagnetic observatories. It plays a decisive role in data quality control and instrument calibration. As modern fluxgate theodolite in absolute geomagnetic measurements has a high precision, usually with 1 second of arc, the measurement results are susceptible to external factors. The personal difference is one of these factors, and it has become an important factor that cannot be ignored in measurement results. In order to estimate the personal difference, an experiment has been designed. Six fluxgate theodolites were used and six observers who were proficient in absolute measurements were invited to this experiment. Then observers made the absolute geomagnetic measurements in turns, and the personal difference among the observers for each instrument was computed by comparing baseline values. Finally, the personal difference can be estimated by a statistical method. [ABSTRACT FROM AUTHOR]

Recent studies show that the combined use of Large-Volume Metrology (LVM) systems (e.g., laser trackers, rotary-laser automatic theodolites (R-LATs), photogrammetric cameras, etc.) can lead to a systematic reduction in measurement uncertainty and a better exploitation of the available equipment. Unfortunately, the sensors of a specific LVM system are usually able to localize only specific targets (i.e., active/passive elements positioned in the measurement volume) and not necessarily those related to other systems (e.g., the reflective markers for photogrammetric cameras cannot be used for R-LATs or laser trackers); this represents an obstacle when using combinations of different LVM systems. This paper describes the design of a new modular probe, with different typologies of targets and integrated sensors, which allows to simplify the measurement process. The probe is versatile as the number of targets, their typology and spatial position can be customized depending on the combination of LVM systems in use. A detailed analysis of the technical and functional characteristics of the probe is followed by the presentation of a mathematical/statistical model for the real-time probe localization. Description is supported by realistic application examples. [ABSTRACT FROM AUTHOR]

A north-seeking data quality optimization method for a magnetically suspended gyroscope is proposed based on two-position characteristics combined with the north-seeking characteristic principle of the magnetically suspended gyroscope total station theodolite. First, a simple linear regression model is established based on the linear relationship satisfied by the rotor current of two precise seeking positions and the north-seeking azimuth. Then, the confidence interval of the corresponding rotor current is calculated from the a priori value of the north-seeking azimuth, and the rotor current data outside the confidence interval are removed. Lastly, the gyroscope azimuth is recalculated. Engineering test data were used to test the effectiveness of the method, and the results showed that the method is effective at testing the north-seeking data quality of the gyroscope and correcting directional results. [ABSTRACT FROM AUTHOR]

At geomagnetic observatories the absolute measurements are needed to determine the calibration parameters of the continuously recording vector magnetometer (variometer). Absolute measurements are indispensable for determining the vector of the geomagnetic field over long periods of time. A standard DI (declination, inclination) measuring scheme for absolute measurements establishes routines in magnetic observatories. The traditional measuring schema uses a fixed number of eight orientations (Jankowski et al., 1996). We present a numerical method, allowing for the evaluation of an arbitrary number (minimum of five as there are five independent parameters) of telescope orientations. Our method provides D, I and Z base values and calculated error bars of them. A general approach has significant advantages. Additional measurements may be seamlessly incorporated for higher accuracy. Individual erroneous readings are identified and can be discarded without invalidating the entire data set. A priori information can be incorporated. We expect the general method to also ease requirements for automated DI-flux measurements. The method can reveal certain properties of the DI theodolite which are not captured by the conventional method. Based on the alternative evaluation method, a new faster and less error-prone measuring schema is presented. It avoids needing to calculate the magnetic meridian prior to the inclination measurements. Measurements in the vicinity of the magnetic equator are possible with theodolites and without a zenith ocular. The implementation of the method in MATLAB is available as source code at the GFZ Data Center (Brunke, 2017). [ABSTRACT FROM AUTHOR]

Gyro theodolites – briefly gyros – allow the orientation transfer from a reference line to another line without need for a connecting geodetic network. They are routinely used for orientation control of networks in tunnelling projects. This is currently the only way to stabilize accuracy and reliability in tunnelling networks and is indispensable with respect of today’s requirements for excavation and breakthrough accuracy. In order to archive a reliable assessment of correctness, the measuring method has to be planned in a way that systematic influences in the determination of an underground directional angle are minimized. For this purpose, the principle of differential measurements is used for an azimuth determination both in terms of time as well as in space. All required corrections and reductions must be considered correctly to obtain the directional angle of interest with a measurement uncertainty less than 1 mgon (⩠3.3′′). Some accuracy considerations obtained from own experiences are discussed to state whether the specified standard deviations of the used gyros according to DIN 18723-7 can be confirmed. [ABSTRACT FROM AUTHOR]

In this paper, tests of plug-pin joints are conducted in order to obtain their mechanical parameters, including semi-rigid property. To solve the difficulties of multi-point displacement measurements for small joints, this investigation proposes a visionbased measurement system based on the principle of binocular stereo vision to improve measurement accuracy. Accurate subpixel location is achieved according to a template-matching algorithm based on grayscale. Joint performance, including horizontal bar joint tension and compression, semi-rigidity between horizontal bars and upright rods and bracing tension and compression, is investigated in order to acquire joint failure modes as well as load and displacement (or moment and rotation angle) curves. Through data fitting, multi-linear simplified models are proposed to illustrate the joints' mechanical performance. This paper also investigates geometric imperfection of temporary member structure with plug-pin joints based on several substructure models and temporary grandstand units using a total station theodolite. The probabilistic models of initial member out-of-straightness and story frame out-of-plumb have been acquired, which can be used into Monte Carlo simulation to create stochastic model of the temporary member structure. [ABSTRACT FROM AUTHOR]

At present, remote human signature detection plays an increasingly important role in the field of anti-terrorism and security defense all around the world. In order to acquire remote, non-cooperative human signature signals, a double mode (audio/video) surveillance system is developed. The system mainly consists of a Laser Doppler Vibrometer (LDV), a pan-tilt-zoom (PTZ) camera and a theodolite. The LDV is used to acquire remote audio by detecting the vibration of the object (caused by the acoustic pressure). The PTZ camera is used to capture the video of the human body, and track the body when he/she moves, then analyze the image to select a proper vibrating target for LDV measurements. The theodolite is applied to control the orientation of the LDV. For the reason that many noise sources disturb the LDV-measured signals, such as laser speckle noises, environmental noises and the noises caused by sensor moving, a kind of speech enhancement technology (OM-LSA algorithm) is used to improve the intelligibility of the noisy voice signals detected by the LDV system. Experiments results indicated that the SNR and MOS of the LDV speech signal (the range is 150 m) can be increased by 135% and 26% respectively by using the speech enhancement technology, and the remote speech and video signals (the range is 30 m) can be obtained by the double-mode surveillance system. [ABSTRACT FROM AUTHOR]

Geomagnetic observatories use classical theodolites equipped with single-axis flux-gate magnetometers known as declination-inclination magnetometers (DIM) to determine absolute values of declination and inclination angles. This instrument and the measurement method are very reliable but need a lot of handwork and experience. The authors developed and built a non-magnetic theodolite which gives all measurement data in digital form. Use of this instrument significantly decreases the possibility of observation errors and minimises handwork. The new instrument is presented in this paper together with first measurement results in comparison to the classical DIM. [ABSTRACT FROM AUTHOR]

The determination of magnetic declination angle entails finding two directions: geographic north and magnetic north. This paper deals with the former. The known way to do it by using the sun's calculable orientation in the sky is improved by using a device based on a WIDIF DIflux theodolite and split photocells positioned on its telescope ocular. Given the WIDIF accurate timing and location provided by the onboard GPS receiver, an astronomical computation can be effected to accurately and quickly determine the sun's azimuth and an auxiliary mark's azimuth. The precise sun's crossing of the split photocell, amplified by the telescope's magnification, allows azimuth accuracies of a few seconds of arc. [ABSTRACT FROM AUTHOR]

Aerospace as a whole, primarily aviation and planes, for a short time after 1903, greatly advance the frontiers of human activity. Initially, unsafe "flying device" the plane, has become a factor in loose resolving wars and one of the reliable means of transport and communication between people around the world. Quick technical and technological development required a special approach. Mass production and use of aircraft, brought in light the need for standardization in the production, testing and lead into operational use of combat aircraft, as well as in commercial use for the purposes of air traffic. Testing the aircraft, is now more disciplinary research activity of a large number of experts from various fields, including test pilot who is an irreplaceable member. At that goal the test-measuring equipment (IMO), are specifically designed, and test pilots are trained in specialized schools for the experiment pilots. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims at the description and comparison of methods of topographic analysis of racing courses at all disciplines of alpine skiing sports for the purposes of obtaining: terrain geomorphology (snowless and with snow), course geometry, and competitors' runs. Methods: The review presents specific methods and instruments according to the order of their historical appearance as follows: (1) azimuth method with the use of a compass, tape and goniometer instruments; (2) optical method with geodetic theodolite, laser and photocells; (3) triangulation method with the aid of a tape and goniometer; (4) image method with the use of video cameras; (5) differential global positioning system and carrier phase global positioning system methods. Results: Described methods were used at homologation procedure, at training sessions, during competitions of local level and during International Ski Federation World Championships or World Cups. Some methods were used together. Conclusions: In order to provide detailed data on course setting and skiers' running it is recommended to analyse course geometry and kinematics data of competitors' running for all important competitions. [ABSTRACT FROM AUTHOR]

Purpose The purpose of this study is to address the concept and the step-by-step procedure of a high-precision optical alignment test for spacecrafts using digital theodolites. The proposed scheme focuses on the non-contact alignment qualification of spacecraft components during the integration and test phases until the launch event.Design/methodology/approach The proposed approach is based on the exploitation of the auto-collimation feature of theodolites and several prisms attached to the requested component and satellite configuration. As soon as the misalignment measurement including the difference between the real and desired attitude or position aberration of an instrument is made, the results must be transformed from the component level to the system level for misalignment error identification in the spacecraft dynamic model.Findings The paper introduces the main instruments, the defined coordinate systems and the architecture of the optical spacecraft misalignment test. Moreover, the guideline of the test implementation and the resulting data process have been presented carefully.Research limitations/implications There is no limitation associated with this method because the procedure is applicable for high-precision typical missions.Practical implications This paper describes a fully implementable scheme to examine any possible inaccuracy in mounting of the spacecraft components both in position and orientation. The test can be performed without the need for a huge budget or complicated hardwares.Originality/value The contribution of this work revolves around illustrating the context and procedure of the spacecraft misalignment test which has remained unknown in literature despite the frequent implementation in the different satellite projects. [ABSTRACT FROM AUTHOR]

To address the limitation of the existing UAV (unmanned aerial vehicles) photoelectric localization method used for moving objects, this paper proposes an improved two-UAV intersection localization system based on airborne optoelectronic platforms by using the crossed-angle localization method of photoelectric theodolites for reference. This paper introduces the makeup and operating principle of intersection localization system, creates auxiliary coordinate systems, transforms the LOS (line of sight, from the UAV to the target) vectors into homogeneous coordinates, and establishes a two-UAV intersection localization model. In this paper, the influence of the positional relationship between UAVs and the target on localization accuracy has been studied in detail to obtain an ideal measuring position and the optimal localization position where the optimal intersection angle is 72.6318°. The result shows that, given the optimal position, the localization root mean square error (RMS) will be 25.0235 m when the target is 5 km away from UAV baselines. Finally, the influence of modified adaptive Kalman filtering on localization results is analyzed, and an appropriate filtering model is established to reduce the localization RMS error to 15.7983 m. Finally, An outfield experiment was carried out and obtained the optimal results: σB = 1.63 x 10-4 (°), σL = 1.35 x 10-4 (°),σH = 15.8 (m), σsum = 27.6 (m), where σB represents the longitude error, σL represents the latitude error, σ L represents the altitude error, and σsum represents the error radius. [ABSTRACT FROM AUTHOR]

Civil engineering projects require the orthometric height of points (i.e., the height of points above geoid). Thus, to make use of the Global Navigation Satellite System (GNSS) in engineering surveying, geoid undulation (i.e., the separation between an ellipsoid and geoid surface) must be known. In this study, an attempt has been made to determine the geoid undulation using the astro-geodetic method. Observations were taken in a network of seven stations spread over 300 km2 around Dehra Dun, India. Astronomical observations of seven stars belonging to different constellations were taken with a theodolite having a least count of 1.0 s. Global positioning system (GPS) observations were taken using dual-frequency geodetic GPS receivers with a 0.1-mm-accurate digital level. Values of astro-geodetic geoid undulations (of stations) have been found close to that computed from field levelling. Further, the values have been compared with those obtained from global geoid models such as EIGEN6C3stat and EGM2008, and the astro-geodetic method was found to provide better accuracy than the global geoid models. Therefore, it can be concluded that the astro-geodetic method is the better choice for reducing GPS observation to orthometric height. In the future, the astro-geodetic method may be used to develop an accurate geoid model in general and for Indian topography in particular. [ABSTRACT FROM AUTHOR]

Non-orthogonal shaft laser theodolite (N-theodolite) is a new kind of large-scale metrological instrument made up by two rotary tables and one collimated laser. There are three axes for an N-theodolite. According to naming conventions in traditional theodolite, rotary axes of two rotary tables are called as horizontal axis and vertical axis, respectively, and the collimated laser beam is named as sight axis. And the difference between N-theodolite and traditional theodolite is obvious, since the former one with no orthogonal and intersecting accuracy requirements. So the calibration method for traditional theodolite is no longer suitable for N-theodolite, while the calibration method applied currently is really complicated. Thus this paper introduces a novel calibration method for non-orthogonal shaft laser theodolite measurement system to simplify the procedure and to improve the calibration accuracy. A simple two-step process, calibration for intrinsic parameters and for extrinsic parameters, is proposed by the novel method. And experiments have shown its efficiency and accuracy. [ABSTRACT FROM AUTHOR]

The study of glacier fronts combines different geomatics measurement techniques as the classic survey using total station or theodolite, technical GNSS (Global Navigation Satellite System), using laser-scanner or using photogrammetry (air or ground). The measure by direct methods (classical surveying and GNSS) is useful and fast when accessibility to the glaciers fronts is easy, while it is practically impossible to realize, in the case of glacier fronts that end up in the sea (tide water glaciers). In this paper, a methodology that combines photogrammetric methods and other techniques for lifting the front of the glacier Johnsons, inaccessible is studied. The images obtained from the front, come from a non-metric digital camera; its georeferencing to a global coordinate system is performed by measuring points GNSS support in accessible areas of the glacier front side and applying methods of direct intersection in inaccessible points of the front, taking measurements with theodolite. The result of observations obtained were applied to study the temporal evolution (1957-2014) of the position of the Johnsons glacier front and the position of the Argentina, Las Palmas and Sally Rocks lobes front (Hurd glacier). [ABSTRACT FROM AUTHOR]

This article reports a novel precise guiding method for visual guiding theodolite measurement in volume space. The vision guiding automatic theodolite measurement system consists of initial guiding and precise guiding, the latter of which directly determines the final measuring accuracy and measuring efficiency. We put forward a precise guiding method based on the camera optical axis. After being calibrated, the double-theodolite measuring subsystem and vision guiding subsystem are triggered by theoretical model data. Then by using the digital image processing technology, we can obtain the relation between the feature center in the camera view and the image center (the camera optical axis). With this relation and the multiresolution visual imaging and tracking technology, the vision measurement subsystem can be guided to target the feature center precisely. According to the calibration relation, we can obtain the angular deflection of double theodolites and make the double theodolites to intersect at the target point precisely. The method improves the automatic measurement efficiency at no cost of measurement accuracy. [ABSTRACT FROM AUTHOR]

Quality control (QC) is among the most important steps in any data processing. These steps are elaborated for high-vertical-resolution radiosonde datasets that were gathered and analyzed to study atmospheric winds. The database is composed of different radiosonde wind-finding systems (WFSs), including radio theodolite, Loran C, and GPS. Inspection of this database, particularly for wind, wind shear, and ascent height increments ( dz), showed a nonnegligible amount of outliers in radio theodolite data as compared to the two other WFSs, thus denoting quality differences between the various systems. An effective statistical QC (SQC) is then developed to isolate and eliminate outliers from the more realistic observations. Improving the accuracy of the radio theodolite WFS is critical to the derivation of the vertical motion and the vertical gradients of the horizontal wind-that is, wind shear-mainly because of the direct dependence of these quantities on dz. Based on the climatological distribution of the quality-controlled dz, a new approach is suggested to estimate these wind quantities for radio theodolite data. The approach is validated with the high-quality modern WFSs (Loran C and GPS). Although initially of reduced quality, applying SQC and using the climatological mean dz of 12-s smoothed radio theodolite profiles shows very good improvement in the climatological wind analyses of radio theodolite WFSs. Notably, the climatologies of ascent rate, vertical motion, horizontal wind, and vertical shear now look comparable for the various WFSs. Thus, the SQC processing steps prove essential and may be extended to other variables and measurement systems. [ABSTRACT FROM AUTHOR]

Estimating the spatial position of organisms is essential to quantify interactions between the organism and the characteristics of its surroundings, for example, predator-prey interactions, habitat selection, and social associations. Because marine mammals spend most of their time under water and may appear at the surface only briefly, determining their exact geographic location can be challenging. Here, we developed a photogrammetric method to accurately estimate the spatial position of marine mammals or birds at the sea surface. Digital recordings containing landscape features with known geographic coordinates can be used to estimate the distance and bearing of each sighting relative to the observation point. The method can correct for frame rotation, estimates pixel size based on the reference points, and can be applied to scenarios with and without a visible horizon. A set of R functions was written to process the images and obtain accurate geographic coordinates for each sighting. The method is applied to estimate the spatiotemporal fine-scale distribution of harbour porpoises in a tidal inlet. Video recordings of harbour porpoises were made from land, using a standard digital single-lens reflex ( DSLR) camera, positioned at a height of 9.59 m above mean sea level. Porpoises were detected up to a distance of ~3136 m (mean 596 m), with a mean location error of 12 m. The method presented here allows for multiple detections of different individuals within a single video frame and for tracking movements of individuals based on repeated sightings. In comparison with traditional methods, this method only requires a digital camera to provide accurate location estimates. It especially has great potential in regions with ample data on local (a)biotic conditions, to help resolve functional mechanisms underlying habitat selection and other behaviors in marine mammals in coastal areas. [ABSTRACT FROM AUTHOR]

The direction cosine location method which is used in traditional optical geometric intersection is simple, so it is widely used in engineering practice. But this method is greatly influenced by the geometric relationship, and cannot inhibit the measuring error, so its positioning accuracy is unsatisfactory. In addition, it cannot be used to compute the locations with more than three stations at a time. A new positioning method with multi-optical theodolites is proposed based on Hermite function restriction. This method can be called function restricted EMBET method. This method uses Hermite function to express the positioning parameters to compress the number of parameters to be estimated, and meanwhile the measuring elements of optical theodolite can be expressed. The measuring equation can be formed by measuring data of multiple measuring elements. Based on least square criterion, the positioning parameters are obtained by computing the combined equation, and the system errors of measuring elements are calibrated. Through the calculation of simulated example, the function restricted EMBET method is compared with the direction cosine location method. The result shows that the function restricted EMBET method is more accurate and more practical. [ABSTRACT FROM AUTHOR]

Offset and its long-term stability is a weak point of fluxgate sensors. Even the ultrastable sensors kept at no vibrations and stable temperature at magnetic observatories show offset drift. Such drift of the fluxgate triaxial sensor can only be partly corrected by the scalar resonance magnetometer. Periodical calibration of absolute reading should be made using nonmagnetic theodolite. In this paper, we study the origin of fluxgate offset. We distinguish the real magnetic sensor offset from the offset contributions originating in the false second harmonics signal that leaks to the sensor output from the distortion in the excitation signal, or which is borne as harmonic distortion when the signal processing electronics are subjected to the large first harmonic signal leaking from the excitation. We analyze the offset dependence on the angular position of the sensor core and its response to large field shocks. The experiments give an indication that only a part of the magnetic offset stems from a remanence of magnetically hard core regions. The residual part may be caused by a magnetostrictive signal, belonging to false signal contributions, but not considered in previous studies. [ABSTRACT FROM AUTHOR]

There is a vast number of geodetic angle measurement equipment (like techeometers, theodolites, laser scanners etc.) implemented in the geodesy, civil engineering, construction engineering etc. The accuracy of measurement of mentioned equipment directly influence the quality of buildings, private state measures etc. Though there is a methodology of testing of such equipment officially adopted, such methodology allows determination of solely random errors of measurements at several angular positions of the instrument. The accuracy (random errors and biases) is still unknown for huge part of the angular values generated by the instrument while measurements. In the paper the theoretical assumptions on possible increasing the measurements accuracy by means of precise calibration in a bigger range of possible measurements is described together with some examples of practical solution of the problem. [ABSTRACT FROM AUTHOR]

Abstract: The goal of the OPERA experiment is to give the first direct evidence for neutrino oscillations in the channel . The OPERA detector is designed to observe the appearance of tau neutrinos in the originally pure muon neutrino CNGS beam. An important part of the magnetic spectrometer is the Precision Tracker (PT), a drift tube detector consisting of 9504 drift tubes. Its main task is the determination of the muon charge and momentum. The alignment strategy for the PT consists of two parts: the hardware measurement by theodolite and the software alignment using long muon tracks. In this paper, the hardware and the software alignment are described, and the track-based alignment methods are explained in detail. Results of the software alignment are presented with a focus on the analysis of cosmic particles. [Copyright &y& Elsevier]

This paper presented a kind of measurement method based on the tree images taken by a single CCD camera mounted on a theodolite. Based on the tree images, it employed some approaches,including threshold segmentation, open computing, and edge detection, to extract the two-dimensional coordinates of the DBH; using the theodolite gathered space angle information, coordinate transformation among the theodolite rotating coordinate system, the camera optical center coordinate system and the image coordinate system, was made to get the three-dimensional coordinates of the DBH, with which the diameter at the breastheight size could be figured out. It took the breast-height diameters of 8 trees in the experiment, and the mean absolute error was 7. 36 mm, while the mean relative error was 2. 46%, which could completely meet the accuracy requirements. The results of the experiments show that the single CCD camera and the theodolite use in DBH measurement method is feasible. [ABSTRACT FROM AUTHOR]

This research aimed to analyze double meridian distance for a closed traverse area in developing a land title for a propose gymnasium in Qassim University. Theodolite, leveling rod and steel tape plays an important role in measuring elevations, bearings and distances of the boundaries of a lot. Contour map is necessary to determine the traces of level surfaces of successive elevation. This will enable to identify the type of contour map and type of contour lines necessary for this project. Corel draw software is used to draw contour map and guide to interpret the significance of the variables. It is essential to check the error of closure for interior angles and for both latitude and departure before applying the Double Meridian Distance (DMD) method to obtain the total area of the lot. Technical descriptions of the land such as distance, bearing, boundaries and area are necessary to visualize the shape & exact location of the land. Developing a land title will be obtained using the technical descriptions of the lot in preparation for the type of gymnasium necessary for Qassim University. [ABSTRACT FROM AUTHOR]

There are multiple instruments directly implementing the principle of angle measurements (horizontal and vertical) for its functioning, used in geodesy, surveying and machine building (like tacheometers, theodolites, laser scanners, laser trackers etc.). As for the moment, there is no official reglamentation regarding calibration and testing of such instrumentation in entire range of the measurements, though instrumentation produce a huge number of both horizontal and vertical angular values during its normal implementation. In the paper the theoretical assumptions of such instrumentation testing and calibration together with examples of some practical tests are given. [ABSTRACT FROM AUTHOR]

The composition of the laser tracking uncooperative target system by active illumination was introduced. The tracking errors that contained the detecting error of detector, the coaxial error of the axis of laser and receiving telescope, and the pointing error of theodolite were researched. The simulation experiment of the tracking was successfully achieved by a simulating experiment with a moving target. The tracking error in the experiment was 30 μrad. In order to make a comparison with the laser tracking uncooperative target system, the composite axis system was used to do the contrast experiment. The laser tracking uncooperative target system using quadrant silicon avalanche photodiodes (QAPD) could obtain a fine tracking precision compared with the composite axis system according to the experimental results. [ABSTRACT FROM AUTHOR]

In some computer vision applications, it is necessary to calibrate the geometry relationships of nonoverlapping cameras. However, due to lacking a common field of view, the calibration of this camera topology is quite difficult. A calibration method for nonoverlapping cameras is proposed and investigated. The proposed method utilizes several light planes, which can be generated by a line laser projector or a rotary laser level, as the calibration objects. The fact that local light planes available in different cameras are identical in global coordinates is used to recover the geometries. Results on both synthetic and real data show the validity and performance of the proposed method. The given method is simple and flexible, which can be used to calibrate geometry relationships of cameras located in large-scale space without expensive equipment such as theodolites and laser trackers. [ABSTRACT FROM AUTHOR]

Abstract: Typically, optical measurement systems can achieve high accuracy over a limited volume, or cover a large volume with low accuracy. In this paper, we propose a universal way of integrating a camera with a theodolite to construct a theodolite-camera (TC) measurement system that can make measurements over a large volume with high accuracy. The TC inherits the advantages of high flexibility and precision from theodolite and camera, but it avoids the need to perform elaborate adjustments on the camera and theodolite. The TC provides a universal and flexible approach to the camera-on-theodolite system. We describe three types of TC based separately on: (i) a total station; (ii) a theodolite; and (iii) a general rotation frame. We also propose three corresponding calibration methods for the different TCs. Experiments have been conducted to verify the measuring accuracy of each of the three types of TC. [Copyright &y& Elsevier]

The cross-correlation-based image matching method has been widely used to derive ice surface motion information from sequential satellite images through tracking spatial displacements of surface features over time. However, this conventional method is not adequate for handling areas with a high velocity variation, in which case a large search window has to be specified in order to find the correct match points for fast-moving features. The computation involved in the cross-correlation matching with a large search window is often so intensive that only a sparse set of velocity measurements can be attempted. Furthermore, with a greater search window the cross-correlation method is prone to more spurious matches. This article presents a robust multi-scale image matching method to address the deficiencies of the conventional cross-correlation technique. The main idea is to use approximate match points obtained at a coarse resolution as a guide for searching for more precise matches at a higher resolution. A robust local statistical operator is embedded at each scale in the multi-scale matching process to eliminate match outliers. The strategy of progressively refining the match precision from coarse-resolution images to the full-resolution image allows for a small search range in pixels. Our robust multi-scale matching method significantly speeds up the computation and also reduces the occurrences of bad and spurious match points. We have implemented our method as a software tool with a graphical user interface and successfully applied it to process sequential Radarsat synthetic aperture radar images for extracting high-resolution velocity fields for Antarctic glaciers and ice shelves. This software tool will be freely available to the public through the Internet. [ABSTRACT FROM AUTHOR]

The article presents a study on the effectiveness of a sun-tracking method to improve the pointing accuracy of weather radar antenna. It offers information on the method which is based on the similarity between radar systems, theodolites, and sun echoes to correct the instrument's errors. It discusses how the study was conducted which revealed that the method has improved the weather radar's pointing accuracy.