Measuring the Speed of Docking Ship with Total Station

The big modern ships are the largest mobile objects that exist in nowadays world. Their huge mass and length in combination with their limited maneuverability can result in the risk of extreme destructions of the infrastructure, as well as environment, in the case of even minor malfunction of any of its elements. The main danger is the kinetic energy of such a colossus and in these circumstances the accuracy of information on the ship's speed becomes particularly important. This is the reason of a growing interest in various systems designed to support harbor pilots during the maneuvers. The most popular ones are based on laser-measurement of the distance, as the rule, installed as static installation in the quay. This article presents the results of the experiments of vessel’s speed measurements when approaching the quay with use the geodetic total stations in a reflectorless variant.

Analisis Perbandingan Ketelitian Model 3D Menggunakan Lensa Normal dan Lensa Fisheye

Dalam pemodelan 3D, salah satu metode yang umum digunakan adalah close range photogrammetry (CRP). Pada umumnya, metode CRP menggunakan lensa normal akibat distorsinya yang tidak terlalu besar. Lensa fisheye memiliki sudut pandang yang lebih besar dibandingkan lensa normal sehingga dapat mengurangi jumlah foto namun memiliki distorsi yang besar sehingga dapat mempengaruhi ketelitian model 3D yang dihasilkan. Penelitian ini bertujuan untuk melakukan pengujian ketelitian geometrik antara lensa normal dan lensa fisheye. Penelitian dilakukan di Kawasan Candi Ratu Boko. Data yang digunakan adalah foto objek candi, 10 titik GCP dan 10 titik ICP. Hasil model 3D lensa normal dan lensa fisheye sudah dapat memvisualisasikan objek dengan baik dari tingkat kedetilan dari struktur yang dihasilkan. Uji geometrik dilakukan dengan membandingkan jarak pada kedua model dengan jarak di lapangan serta ukuran ICP pada kedua model dengan ukuran ICP hasil akuisisi mengunakan total station reflectorless. Kedua uji tersebut menggunakan uji -t dengan tingkat kepercayaan 95%. Uji ketelitian jarak dan koordinat ICP menghasilkan t hitung < tabel sehingga dapat disimpulkan bahwa ketelitian model 3D lensa fisheye sama dengan ketelitian model 3D lensa normal. Lensa fisheye dapat menggantikan lensa normal untuk pemodelan 3D dalam kondisi lingkungan yang sempit dan terbatas. Distorsi lensa yang besar pada lensa fisheye tidak mempengaruhi ketelitian objek secara signifikan apabila dilakukan proses kalibrasi kamera.

Accuracy Assessment of Post-processing Kinematic Georeferencing Based on Real-time Kinematic Unmanned Aerial Vehicle and Structure-from-motion Photogrammetry: Topographic Measurements of a Riverbed in a Small Watershed with a Check Dam

<p><a>To obtain an accurate digital surface model of the small watershed topography of a forested area while reducing time and labor costs, we used a consumer-grade unmanned aerial vehicle (UAV) with a build-in real-time kinematic global navigation satellite system. The applicability of structure-from-motion (SfM) multi-view stereo processing with post-processing kinematic (PPK) correction of the positional coordinate data (the UAV-PPK-SfM method) was tested. Nine verification points were set up in a small (0.5 km²) watershed, based on a check dam in the headwaters of a forest area. The location information of the verification points extracted from the digital surface model acquired by UAV-PPK-SfM and the overall working time were compared with the corresponding location information and working time of a traditional field survey using a total station. The results showed that the vertical error between the total station and each verification point at an altitude of 150 m ranged from 0.006 to 0.181 m. The working time of the UAV-PK-SfM survey was 10 % of that of the total station survey (30 min). The UAV-PPK-SfM workflow proposed in this study shows that wide-area, non-destructive topographic surveying, including fluvial geomorphological mapping, is possible with a vertical error of ±0.2 m in small watersheds (<0.5 km²). This method will be useful for rapid topographic surveying in inaccessible areas during disasters, such as monitoring debris flow at check dam sites, and for efficient topographic mapping of steep valleys in forested areas where the positioning of ground control points is a laborious task.</a></p>

Accuracy Assessment of Post-processing Kinematic Georeferencing Based on Real-time Kinematic Unmanned Aerial Vehicle and Structure-from-motion Photogrammetry: Topographic Measurements of a Riverbed in a Small Watershed with a Check Dam

<p><a>To obtain an accurate digital surface model of the small watershed topography of a forested area while reducing time and labor costs, we used a consumer-grade unmanned aerial vehicle (UAV) with a build-in real-time kinematic global navigation satellite system. The applicability of structure-from-motion (SfM) multi-view stereo processing with post-processing kinematic (PPK) correction of the positional coordinate data (the UAV-PPK-SfM method) was tested. Nine verification points were set up in a small (0.5 km²) watershed, based on a check dam in the headwaters of a forest area. The location information of the verification points extracted from the digital surface model acquired by UAV-PPK-SfM and the overall working time were compared with the corresponding location information and working time of a traditional field survey using a total station. The results showed that the vertical error between the total station and each verification point at an altitude of 150 m ranged from 0.006 to 0.181 m. The working time of the UAV-PK-SfM survey was 10 % of that of the total station survey (30 min). The UAV-PPK-SfM workflow proposed in this study shows that wide-area, non-destructive topographic surveying, including fluvial geomorphological mapping, is possible with a vertical error of ±0.2 m in small watersheds (<0.5 km²). This method will be useful for rapid topographic surveying in inaccessible areas during disasters, such as monitoring debris flow at check dam sites, and for efficient topographic mapping of steep valleys in forested areas where the positioning of ground control points is a laborious task.</a></p>

Terrestrial photogrammetry at the quarry and validating the accuracy of slope models for monitoring their stability

The paper is devoted to the application of photogrammetry in surveying and geomechanical studies of the state of stability of slopes in a quarry. For deep quarries a particularly important task is to ensure the stability of the slopes of the benches. The purpose of this study is to improve the survey techniques of the slopes using terrestrial photogrammetry, the establishment of the values of the basic errors in the positioning of cameras in local geodetic network. The results of photogrammetric measuring data processing, which are the coordinates of the slope points and its elements, point cloud, surface model, volume and area data, improve the quality of geomechanical monitoring at mining enterprises and provide increase safety of mining operations. The proposed method of survey consists in positioning images (projection centres) in the system of the geodetic reference network by measuring with an electronic total station. Established during the study was dependence of the accuracy of the coordinates of the three-dimensional model of the slopes on the distance between the camera and the total station, between the camera positions in a pair of images. The article contains the results of the practical implementation of the proposed survey method, the results of experiments performed for the purpose of comparison with an alternative measurement method, which was a survey by a total station, graphs of dependencies describing the effect of measurement parameters on the accuracy of work performed. The article is also supplemented by a theoretical analysis of the use of UAVs in the use of work to determine of stability of slopes in a quarry, which is based on the authors’ experience with the use of UAVs in open pit mines. In this theoretical comparison, the emphasis is mainly on the operability of the use of UAV, which in the case of open pit mines creating a practically stable wind vortex with a speed higher than the allowed speed of operation rotors UAVs.

STUDI PERBANDINGAN ANALISA KETELITIAN TINGGI MENGGUNAKAN TOTAL STATION DAN SIPAT DATAR

This research was conducted to analyze and determine the height difference accuracy using the method of measuring the different heights of a closed loop using Waterpass B2 and Total Station Kolida 420SR. The location of research in the Ciloto area, Puncak, West Java with coordinates 107˚ east longitude and 06˚ south latitude, on 14-15 December 2014 using a local high point reference. Measurements were made three times with different looped but the starting and ending points were the same points. Accuracy of calculation is done by calculating the average of the least squares to determine the standard deviation of the measurement results with each equipment. The result is the standard deviation of the height difference with the waterpass is 0.01mm, while with the Total Station it is 0.02 mm. Based on the results of the standard deviation of the height difference, the Total Station can be used for height measurements in civil engineering project that does not require very high accuracy and height difference measurements with the Total Station are more economical because the time required for measurement is a quarter of the time required height difference measurement with Waterpass. Keywords: height measurement; Waterpass; Total station. AbstrakPenelitian ini dilakukan untuk menganalisis dan mengetahui ketelitian beda tinggi menggunakan metode pengukuran beda tinggi suatu ring tertutup menggunakan Waterpass B2 dan Total Station Kolida 420SR. Lokasi penelitian terletak di daerah Ciloto, Puncak Jawa Barat dengan koordinat 107o bujur timur dan 06o lintang selatan, pada tanggal 14 dan 15 Desember 2014 dengan menggunakan referensi titik tinggi lokal. Pengukuran dilakukan tiga kali dengan ring yang berbeda namun titik pangkal dan ujung adalah titik yang sama. Hitungan ketelitian dilakukan dengan hitung perataan kuadrat terkecil untuk mengetahui standar deviasi hasil pengukuran dengan masing-masing alat. Hasilnya adalah standar deviasi beda tinggi dengan waterpass sebesar 0.01mm, sedangkan dengan Total Station sebesar 0.02 mm. Berdasarkan hasil perhitungan nilai standar deviasi pengukuran beda tinggi, maka Total Station dapat digunakan untuk pengukuran beda tinggi pada pekerjaan teknik sipil yang tidak memerlukan ketelitian yang sangat tinggi, dan pengukuran beda tinggi dengan Total Station lebih ekonomis karena waktu yang diperlukan untuk pengukuran adalah seperempat dari waktu yang diperlukan pengukuran beda tinggi dengan Waterpass.

FREE STATION TASK WITH DRONE

Using drones with different purposes than only taking photos is nowadays the main direction of drone development. Drones are made for package delivery, people transport, etc. Drone equipped by GNSS RTK and prism can be used as orientation point for the free station. The idea is using drone to get coordinates of total stations inappropriate for GNSS. such as high buildings and forest. The drone can fly above the obstacle causing inappropriate, so the GNSS will compute the position coordinates correctly. Total station will measure distance and angles on prism to get free station coordinates. This article deals with the accuracy of using two points in the free station task. Accuracy of measurement and data is based on real values. Drone can be used as the target if it is not windy, the position accuracy of the target on drone is 5 cm. Wind has no effect on the vertical position accuracy of the the drone. The results show that the same principles and limitations must be observed when measuring the free station task. Horizontal angle between orientation points must be bigger than 100 gon and the zenith angle must be at least 50 gon. The distance between orientation and free station must longer than consequent measured points.

Stage of Potential Identification Irrigation Channel Topography Analysis for Micro-Hydro Power in the Kalibawang Irrigation Primary Channel, Yogyakarta, Indonesia

This study was designed to determine the stages in the identification of micro-hydro in irrigation channels based on the classification and level of data requirements in a project, starting from the initial study, feasibility study and detailed engineering design. The study was conducted with site selection criteria using four information systems and technology tools, namely Google Earth, GIS Topography, UAV Drone Phantom DJI 4, and Nikkon DTM 332 Total Station. The results shows through GE and GIS, obtained 23 potential points, 7 of which are high potential, followed by field measurements with 1 selected UAV location Cascade, and detailed with TS to produce Head (H) 12 m, with CM and FDC probability 75% discharge (Q) 5.5 m3/s, generated power (P) 550 kW. This study provides a method and solution for speed in identifying potential with Google Earth and GIS (Macro Class), speed and risk reduction for surveyors with UAVs (Mezo Class), and accuracy and detailing at selected locations with Total Station (Micro Class). So that this research provides accuracy in the stages, methods and tools used in the identification of micro-hydro potential in irrigation channels.