EVALUATION AND CALIBRATION OF FIXED-WING UAV MOBILE MAPPING SYSTEM EQUIPPED WITH LIDAR AND OPTICAL SENSORS

In this paper, a mobile mapping system mounted on the UAV is presented and evaluated. The NEO3 UAV platform is an 11 kg fixed-wing designed by the MSP company. The UAV is equipped with a Riegl miniVUX-1UAV laser scanner, which is integrated with the GNSS/INS system of Applanix APX-15 UAV and two Sony Alfa 6000 cameras collecting images in the following spectrum: visible for the first camera and near-infrared for the second camera. The UAV mobile system presented is dedicated to the acquisition of multisource data for levee monitoring using active and passive remote sensing data. In this paper, the effectiveness of the ultralight laser scanner, which has not been mounted on the fixed-wing platforms so far, was verified in the experiment with respect to data density and accuracy. The example analyses were conducted using ground control points and surfaces measured with a terrestrial laser scanner and visible in point clouds obtained with a dense image matching algorithm. Analyses showed that the achieved accuracy is much related to trajectory accuracy. The final DTM created from the data collected during the float status of the GNSS measurements of the trajectory provided twice less accurate data than during fixed status (vertical error approximately 20 cm and 10 cm respectively)

Modernizacja ewidencji gruntów i budynków na terenach gdzie funkcjonują mapy ewidencyjne w skali 1:2880 z wykorzystaniem metod fotogrametrii cyfrowej

Referat prezentuje wyniki prac pilotowych podjętych na zlecenie GUGiK, dotyczących modernizacji ewidencji gruntów i budynków metodami fotogrametrycznymi

Flood hazard maps and flood risk maps and floods directive

W 2007 roku weszła w życie tzw. Dyrektywa Powodziowa nakładająca obowiązek opracowania map zagrożenia i map ryzyka powodziowego do końca 2013 roku. Metodykę opracowania takich map w Polsce określa Rozporządzenie Ministra Środowiska, Ministra Infrastruktury oraz Ministra Spraw Wewnętrznych i Administracji w sprawie opracowania map zagrożenia powodziowego oraz map ryzyka powodziowego. Mapy takie opierają się na aktualnych danych geodezyjnych i kartograficznych, a wśród nich na precyzyjnym numerycznym modelu terenu opracowanym z danych lotniczego skaningu laserowego. Powstał „Projekt Informatyczny System Osłony Kraju przed nadzwyczajnymi zagrożeniami”, określany skrótem ISOK, w ramach którego GUGiK przygotowuje takie dane. Artykuł przybliża metodykę opracowania map oraz zakres Projektu ISOK i poddaje analizie przyjęte założenia techniczne.In 2007 came into force so called Floods Directive imposing an obligation to draw up hazard maps and flood risk maps by the end of 2013. Methodology of developing such maps in Poland determines the Decree of the Minister of the Environment, the Minister for Infrastructure and Minister of the Interior and Administration on the development of flood hazard maps and flood risk maps. Methodology defines, among others, content range of maps, the quality of source data and the timetable for their implementation and publication. Such maps are based on current geodetic and cartographic data, including the precise digital terrain model developed from airborne laser scanning data. The project was created, "The Computer System of the National Guards against exceptional risks", abbreviated ISOK under which GUGiK is preparing such data. The territorial scope of the development includes more than 60% of the country threatened by floods. Work on developing the digital terrain model runs until the end of 2013. As part of the Project, in addition to digital terrain model, digital high resolution orthophotomap for more than 200 cities with 0.10 m terrain pixel size, and elements of Data Base of Topographic Objects will be produced. The article introduces a methodology of development of flood maps, the scope of the ISOK Project and examines the technical assumptions

Generation of countrywide reference digital terrain model from airborne laser scannig in ISOK project

W niniejszej publikacji referacie opisano analizę doboru podstawowych parametrów lotniczego skanowania laserowego mających wpływ na otrzymanie modeli wysokościowych o założonych, referencyjnych parametrach jakościowych na przykładzie lotniczego skanowania laserowego organizowanego w ramach wypełnienia zaleceń dyrektywy powodziowej w Polsce. Analiza taka legła u podstaw określenia warunków technicznych dla bardzo dużego projektu, którego realizacja nadal trwa. Rozważaniom podlegały nie tylko uwarunkowania techniczne, ale również możliwości organizacyjne i ekonomiczne. Pod uwagę wzięto także zakres prac oraz ograniczenia czasowe na ich realizację, co – przy uwzględnieniu wydajności prac – narzuca organizację prac. Spośród parametrów technicznych, analizie poddano m.in.: gęstość chmury punktów ALS, dokładność georeferencji chmur punktów, warunki meteorologiczne pozyskiwania danych ALS, parametry dokładnościowe produktów pochodnych tj. numerycznych modeli wysokościowych. W tak złożonym projekcie (podział robót na podobszary, wielu wykonawców, kilka produktów końcowych, podział na wiele etapów dostaw) kluczowym jest również odbiór i kontrola jakości, o której efektywności świadczy jej organizacja, zakres i przyjęte kryteria.The paper analyzes the selection of main parameters of ALS system having an impact on acquisition of digital elevation models described by the assumed and exorbitant qualitative characteristics on the basis of airborne laser scanning project organized as a part of recommendations included in the Floods Directive in Poland. Such an analysis was the basis for determining conditions for a huge project, whose implementation is still ongoing, as well as its organizational and economic possibilities. Another subject for consideration was the scope of the planned works and time limits for their implementation that imposed the schedule of the project with respect to the efficiency of the work. Among the technical characteristics the authors investigated the density of the LiDAR points, georeferencing of point clouds, meteorological conditions during data acquisition and parameters describing the accuracy of the final products, namely digital elevation models, were also investigated. In such a complex project (the division of the whole project for subareas, many contractors, several final products and many stages of delivery product acceptance as well as quality control are key issues, whose effectiveness is proved by good organization, their scope and the adopted criteria

Photogrammetry at the Warsaw University of Technology - past and present

The Department of Photogrammetry, Remote Sensing and Geographic Information Systems at the Warsaw University of Technology is one of six organizational units of the Faculty of Geodesy and Cartography. The photogrammetry has been under interest of scientists in Faculty for over 90 years. The last decades has been characterized by the incredible development of photogrammetric technologies, mainly towards wide automation and popularization of derivative products for processing data acquired at satellite, aerial, and terrestrial levels. The paper presents achievements of scientists employed in Photogrammetric Research Group during last decades related to projects that were carried out in this department

Mapping of polar areas based on high-resolution satellite images : the example of the Henryk Arctowski Polish Antarctic Station

To produce orthophotomaps or digital elevation models, the most commonly used method is photogrammetric measurement. However, the use of aerial images is not easy in polar regions for logistical reasons. In these areas, remote sensing data acquired from satellite systems is much more useful. This paper presents the basic technical requirements of different products which can be obtain (in particular orthoimages and digital elevation model (DEM)) using Very-High-Resolution Satellite (VHRS) images. The study area was situated in the vicinity of the Henryk Arctowski Polish Antarctic Station on the Western Shore of Admiralty Bay, King George Island, Western Antarctic. Image processing was applied on two triplets of images acquired by the Pléiades 1A and 1B in March 2013. The results of the generation of orthoimages from the Pléiades systems without control points showed that the proposed method can achieve Root Mean Squared Error (RMSE) of 3–9 m. The presented Pléiades images are useful for thematic remote sensing analysis and processing of measurements. Using satellite images to produce remote sensing products for polar regions is highly beneficial and reliable and compares well with more expensive airborne photographs or field surveys

THE POTENTIAL OF LIGHT LASER SCANNERS DEVELOPED FOR UNMANNED AERIAL VEHICLES – THE REVIEW AND ACCURACY

Modern photogrammetry and remote sensing have found small Unmanned Aerial Vehicles (UAVs) to be a valuable source of data in various branches of science and industry (e.g., agriculture, cultural heritage). Recently, the growing role of laser scanning in the application of UAVs has also been observed. Laser scanners dedicated to UAVs consist of four basic components: a laser scanner (LiDAR), an Inertial Measurement Unit (IMU), a Global Navigation Satellite System (GNSS) receiver and an on-board computer. The producers of the system provide users with detailed descriptions of the accuracies separately for each component. However, the final measurement accuracy is not given. This paper reviews state-of-the-art of laser scanners developed specifically for use on a UAV, presenting an overview of several constructions that are available nowadays. The second part of the paper is focussed on analysing the influence of the sensor accuracies on the final measurement accuracy. Mathematical models developed for Airborne Laser Scanning (ALS) accuracy analyses are used to estimate the theoretical accuracies of different scanners with conditions typical for UAV missions. Finally, the theoretical results derived from the mathematical simulations are compared with an experimental use case

DEVELOPING THE STABILIZED MAPPING SYSTEM FOR THE GYROCOPTER – REPORT FROM THE FIRST TESTS

The LiDAR mapping carried out using gyrocopters provides a relatively cheap alternative for traditional mapping involving airplanes. The costs of the fuel and the overall maintenance are much lower when compared to planes. At the same time the flight kinematics of the gyrocopter makes it an ideal vehicle for corridor mapping. However a limited payload and a strongly limited space prevent using stabilized platforms dedicated for aerial photogrammetry. As the proper stabilization of the laser scanner during the flight is crucial in order to keep the desirable quality of the LiDAR data, it was decided to develop the prototype of the stabilized, ultra-light mapping platform that can meet the restricted requirements of the gyrocopter. The paper starts with the brief discussion of the legal and practical aspects of the LiDAR data quality, dealing mostly with the influence of the flight imperfections on the point pattern and point density. Afterwards the mapping system prototype is characterized, taking into account three main components: stabilized platform, sensors and control. Subsequently first in-flight tests are described. Though the data are still not perfect mostly due to vibrations, the stabilization provides a substantial improvement of their geometry, reducing both roll and pitch deflections

Participation of Employees and Students of the Faculty of Geodesy and Cartography in Polar Research

This year the Faculty of Geodesy and Cartography, Warsaw University of Technology celebrates its 95th jubilee, which provides an opportunity to present the Faculty’s rich traditions in polar research. Employees and students of the faculty for almost 60 years have taken part in research expeditions to the polar circle. The article presents various studies typical of geodesy and cartography, as well as miscellany of possible measurement applications and geodetic techniques used to support interdisciplinary research. Wide range of geodetic techniques used in polar studies includes classic angular and linear surveys, photogrammetric techniques, gravimetric measurements, GNSS satellite techniques and satellite imaging. Those measurements were applied in glaciological, geological, geodynamic, botanical researches as well as in cartographic studies. Often they were used in activities aiming to ensure continuous functioning of Polish research stations on both hemispheres. This study is a short overview of thematic scope and selected research results conducted by our employees and students