Article

Using LIDAR data in wireless communication system design

January 2000

Authors:

As the telecommunications industry responds to the rapidly growing demand for wireless services in the commercial and residential sectors, data suppliers are trying to tailor their products to competitively meet the needs of this lucrative market. One such service is a high frequency point-to-multipoint system for urban areas called LMDS (local multipoint distribution service). Two requirements of LMDS provide a challenge for system designers: 1) there must be line of sight between transmitter and receiver, and 2) a fairly dense pattern of transmitters is required because these microwave radio waves travel only a short distance before weakening and dispersing. Therefore, high resolution geographic databases that accurately depict potential signal obstructions—terrain, buildings and major foliage—are necessary. LIDAR technology has emerged as an alternative to the traditional method of using digital orthophotography to derive footprints and elevations of urban features. Its ability to produce high resolution (1-3 meters) databases and sub-meter accuracies has advantages and disadvantages for telecom planning. The detailed picture of the urban landscape can assist engineers as they design high-frequency wireless systems. But the high resolutions may generate an unwieldy amount of data when applied to the entire urban area. In this paper, LIDAR data is used as a basis for signal prediction studies, and suggestions for and issues surrounding its use are discussed.

New Approach in Integrated Basin Modelling: Melen Airborne LIDAR

Article

Full-text available

Apr 2019

Airborne LIDAR technology which has an increasing importance in recent years, has entered into the field of application of many disciplines by obtaining fast and highly accurate 3D data. It provides precise topography information with dense point cloud data as well as all details on the surface. Thus, it has become useful in all disciplines associated with space such as cartography, construction, city planning, forest, energy, hydrology, geology, transportation, telecommunications, security, disaster, aviation, and infrastructure. By mounting LIDAR measurement units on aircraft large areas can be measured relatively quickly and cost-effectively. In this study, Riegl Q680i scanner and CCNS5 flight management system were mounted to the aircraft. The digital elevation models; DEM (Digital Elevation Model) and DSM (Digital Surface Model) of the Melen basin, which is located within the boundaries of Düzce and Sakarya was generated using LIDAR point cloud data (.las format) with a point density of 16 points/m2 and also 1/1000 base maps of the basin were produced. In addition, many details such as road, slope, culvert, electricity poles were drawn in accordance with the principles of large-scale map construction regulations and transferred to GIS environment. The Melen basin with an important water storage area, boundaries, basin model, water collection lines, determination of flow directions and connections, the topographic surface of the basin sub-areas, morphology were created using 3D laser point cloud data. So, the digital terrain model of the basin in GIS environment is visualized with linear maps. LIDAR data provides 3D geometric and morphological information that cannot be obtained according to classical methods in this kind of engineering studies. Results suggest that the higher spatial resolution LIDAR-derived data are preferable and can introduce more detailed information about basin hydro geomorphic behaviours.

Automatic Detection and Reconstruction of 2-D/3-D Building Shapes From Spaceborne TomoSAR Point Clouds

Article

Sep 2015
IEEE T GEOSCI REMOTE

Modern spaceborne synthetic aperture radar (SAR) sensors, such as TerraSAR-X/TanDEM-X and COSMO-SkyMed, can deliver very high resolution (VHR) data beyond the inherent spatial scales of buildings. Processing these VHR data with advanced interferometric techniques, such as SAR tomography (TomoSAR), allows for the generation of four-dimensional point clouds, containing not only the 3-D positions of the scatterer location but also the estimates of seasonal/temporal deformation on the scale of centimeters or even millimeters, making them very attractive for generating dynamic city models from space. Motivated by these chances, the authors have earlier proposed approaches that demonstrated first attempts toward reconstruction of building facades from this class of data. The approaches work well when high density of facade points exists, and the full shape of the building could be reconstructed if data are available from multiple views, e.g., from both ascending and descending orbits. However, there are cases when no or only few facade points are available. This usually happens for lower height buildings and renders the detection of facade points/regions very challenging. Moreover, problems related to the visibility of facades mainly facing toward the azimuth direction (i.e., facades orthogonally oriented to the flight direction) can also cause difficulties in deriving the complete structure of individual buildings. These problems motivated us to reconstruct full 2-D/3-D shapes of buildings via exploitation of roof points. In this paper, we present a novel and complete data-driven framework for the automatic (parametric) reconstruction of 2-D/3-D building shapes (or footprints) using unstructured TomoSAR point clouds particularly generated from one viewing angle only. The proposed approach is illustrated and validated by examples using TomoSAR point clouds generated using TerraSAR-X high-resolution spotlight data stacks acquired from ascending orbit covering two different test areas, with one containing simple moderate-sized buildings in Las Vegas, USA and the other containing relatively complex building structures in Berlin, Germany.

Reconstructing 2-D/3-D Building Shapes from Spaceborne Tomographic Synthetic Aperture Radar Data

Article

Full-text available

Aug 2014

In this paper, we present an approach that allows automatic (parametric) reconstruction of building shapes in 2-D/3-D using TomoSAR point clouds. These point clouds are generated by processing radar image stacks via advanced interferometric technique, called SAR tomography. The proposed approach reconstructs the building outline by exploiting both the available roof and façade information. Roof points are extracted out by employing a surface normals based region growing procedure via selected seed points while the extraction of façade points is based on thresholding the point scatterer density SD estimated by robust M-estimator. Spatial clustering is then applied to the extracted roof points in a way such that each roof cluster represents an individual building. Extracted façade points are reconstructed and afterwards incorporated to the segmented roof cluster to reconstruct the complete building shape. Initial building footprints are derived by employing alpha shapes method that are later regularized. Finally, rectilinear constraints are added to yield better geometrically looking building shapes. The proposed approach is illustrated and validated by examples using TomoSAR point clouds generated from a stack of TerraSAR-X high-resolution spotlight images from ascending orbit only covering two different test areas with one containing relatively smaller buildings in densely populated regions and the other containing moderate sized buildings in the city of Las Vegas.

Robust Reconstruction of Building Facades for Large Areas Using Spaceborne TomoSAR Point Clouds

Article

Full-text available

Feb 2015
IEEE T GEOSCI REMOTE

With data provided by modern meter-resolution synthetic aperture radar (SAR) sensors and advanced multipass interferometric techniques such as tomographic SAR inversion (TomoSAR), it is now possible to reconstruct the shape and monitor the undergoing motion of urban infrastructures on the scale of centimeters or even millimeters from space in very high level of details. The retrieval of rich information allows us to take a step further toward generation of 4-D (or even higher dimensional) dynamic city models, i.e., city models that can incorporate temporal (motion) behavior along with the 3-D information. Motivated by these opportunities, the authors proposed an approach that first attempts to reconstruct facades from this class of data. The approach works well for small areas containing only a couple of buildings. However, towards automatic reconstruction for the whole city area, a more robust and fully automatic approach is needed. In this paper, we present a complete extended approach for automatic (parametric) reconstruction of building facades from 4-D TomoSAR point cloud data and put particular focus on robust reconstruction of large areas. The proposed approach is illustrated and validated by examples using TomoSAR point clouds generated from a stack of TerraSAR-X high-resolution spotlight images from ascending orbit covering an approximately 2- $hbox{km}^{2}$ high-rise area in the city of Las Vegas.

Robust Reconstruction of Building Façades Using Spaceborne Tomographic SAR Data Suitable for Large Areas

Article

Full-text available

May 2014
IEEE T GEOSCI REMOTE

With data provided by modern meter-resolution SAR sensors and advanced multi-pass interferometric techniques such as tomographic SAR inversion (TomoSAR), it is now possible to reconstruct the shape and monitor the undergoing motion of urban infrastructures in the scale of centimeters or even millimeters from space in very high level of details. This retrieved rich information allows us even to take a step further towards generation of 4-D (or even higher dimensional) dynamic city models, i.e. city models that can incorporate temporal (motion) behaviour along with the 3-D information. Motivated by these chances, the authors proposed an approach that first attempts to reconstruct façades from this class of data. The approach works well for small areas containing only a couple of buildings. Yet towards automatic reconstruction for the whole city area, more robust and fully automatic approach is needed. In this paper, we present a complete extended approach for automatic (parametric) reconstruction of building façades from 4-D TomoSAR point cloud and put the particular focus on robust reconstruction of large areas. The proposed approach is illustrated and validated by examples using TomoSAR point clouds generated from a stack of TerraSAR-X high-resolution spotlight images from ascending orbit covering approx. 2 km2 high rise area in the city of Las Vegas.

Urban modeling from LIDAR data in an integrated GIS environment

Article

Full-text available

Lidar (Light Detection and Ranging) is a remote sensing technique utilizing laser technology. It has found applications in a wide variety of fields of study, including atmospheric science, bathymetric data collection, law enforcement and tele-communication. This article focuses on the application of Lidar data to feature extraction and 3D urban modeling. ArcView GIS package along other powerful image processing and 3D modeling extension modules is used for the study. Both interactive and automatic alternative methods are investigated and compared. Problems encountered are analyzed and possible solutions are proposed by fusing lidar data with other image data. Study shows that existing tools can be used to classify the lidar data, convert the results to 3D structured data. After an effective cleaning-up operation, a satisfactory 3-D modeling can be generated. The combination of interactive and automatic extractions demonstrates the most comprehensive and appealing results. Tests of built-up urban area at downtown Baltimore, MD are presented to support the analyses.

Organizing BTS Sites Deployment Based on Urban Planning Goals Using Site Sharing Approach; Case Study: Tehran, Iran

Article