Mobile mapping | EPFL Graph Search

Mobile mapping is the process of collecting geospatial data from a mobile vehicle, typically fitted with a range of GNSS, photographic, radar, laser, LiDAR or any number of remote sensing systems. Such systems are composed of an integrated array of time synchronised navigation sensors and imaging sensors mounted on a mobile platform. The primary output from such systems include GIS data, digital maps, and georeferenced images and video. History The development of direct reading georeferencing technologies opened the way for mobile mapping systems. GPS and Inertial Navigation Systems, have allowed rapid and accurate determination of position and attitude of remote sensing equipment, effectively leading to direct mapping of features of interest without the need for complex post-processing of observed data. Applications Aerial mobile mapping Traditional techniques of geo-referencing aerial photography, ground profiling radar, or Lidar are prohibitiv

Integrated Sensor Orientation on Micro Aerial Vehicles

Martin Rehak

Mapping with Micro Aerial Vehicles (MAVs whose weight does not exceed 5 kg) is gaining importance in applications, such as corridor mapping, road and pipeline inspections, or mapping of large areas with homogeneous surface structure, e.g. forest or agricultural fields. When cm-level accuracy is required, the classical approach of sensor orientation does not deliver satisfactory results unless a large number of ground control points (GCPs) is regularly distributed in the mapped area. This may not be a feasible method either due to the associated costs or terrain inaccessibility. This thesis addresses such issues by presenting a development of MAV platforms with navigation and imaging sensors that are able to perform integrated sensor orientation (ISO). This method combines image measurements with GNSS or GNSS/IMU (Global Navigation Satellite System/Inertial Measurement Unit) observations. This innovative approach allows mapping with cm-level accuracy without the support of GCPs, even in geometrically challenging scenarios, such as corridors. The presented solution also helps in situations where automatic image observations cannot be generated, e.g. over water, sand, or other surfaces with low variations of texture. The application of ISO to MAV photogrammetry is a novel solution and its implementation brings new engineering and research challenges due to a limited payload capacity and quality of employed sensors on-board. These challenges are addressed using traditional as well as novel methods of treating observations within the developed processing software. The capability of the constructed MAV platforms and processing tools is tested in real mapping scenarios. It is empirically confirmed that accurate aerial control combined with a state-of-the-art calibration and processing can deliver cm-level ground accuracy, even in the most demanding projects. This thesis also presents an innovative way of mission planning in challenging environments. Indeed, a thorough pre-flight analysis is important not only for obtaining satisfactory mapping quality, but photogrammetric missions must be carried out in compliance with state regulations.

EPFL2017

Mobile mapping en temps réel pour la saisie automatique d'axes routiers

Hervé Gontran

The development of road telematics requires the management of ever-growing databases related to traffic fluidity, live consignment monitoring and vehicle fleet tracking, as to driver assistance. Such an effort relies on the tight synergy between navigation technology, telecommunication and geographic information, to enhance the maintenance and exploitation of the road network and, above all, to strengthen security. Consequently, an accurate knowledge of the road environment and topology is mandatory to implement applications of transport telematics. The early nineties experienced major advances in GPS/INS coupling and the market launch of affordable digital cameras. Thus, a considerable portion of road information is captured by vehicles equipped with such sensors, a technique known as "mobile mapping". The advantage of the kinematic collection of data – such as the pavement geometry, its surfacing quality and the positioning of road objects – lies in the much faster completion of the survey, hence an excellent cost effectiveness. However, the complexity of data georeferencing and the fusion of the results with video sequences require numerous hours of repetitive labor. Moreover, only the process completion reveals the correct recording of position measurements. Any further survey can only be decided a few days later. We propose to introduce the concept of "real time" in the field of mobile mapping. The determinist exploitation of the data captured during a kinematic survey aims at restricting human intervention in the sophisticated georeferencing process, while authorizing the dissemination of this technique outside well-informed communities. The other challenge of this thesis that lies in the automatic fusion of localization data with images, under tight time constraints. In these conditions, what are the tools and algorithms robust enough to ensure the quality control of the georeferencing of road objects? We intend to provide these concerns a pertinent answer, while demonstrating the validity of the concept via the automatic acquisition and interpretation of the road geometry.

EPFL2007

Fixed-wing Micro Aerial Vehicle for Accurate Corridor Mapping

Martin Rehak, Jan Skaloud

In this study we present a Micro Aerial Vehicle (MAV) equipped with precise position and attitude sensors that together with a pre-calibrated camera enables accurate corridor mapping. The design of the platform is based on widely available model components to which we integrate an open-source autopilot, customized mass-market camera and navigation sensors. We adapt the concepts of system calibration from larger mapping platforms to MAV and evaluate them practically for their achievable accuracy. We present case studies for accurate mapping without ground control points: first for a block configuration, later for a narrow corridor. We evaluate the mapping accuracy with respect to checkpoints and digital terrain model. We show that while it is possible to achieve pixel (3-5 cm) mapping accuracy in both cases, precise aerial position control is sufficient for block configuration, the precise position and attitude control is required for corridor mapping.

2015