Sensors integration for smartphone navigation: performances and future challenges

Nowadays the modern Smartphones include several sensors which are usually adopted in geomatic application, as digital camera, GNSS receivers, inertial platform and RFID system. In this paper the Authors would like to testing the performances of internal sensors (IMU) of three modern smartphones (Samsung GalaxyS4, Samsung GalaxyS5 and iPhone4) compared to external mass-market IMU platform in order to verify their accuracy levels, in terms of positioning. Moreover, the Image Based Navigation (IBN) approach is also investigated: this approach can be very useful in hard-urban environment or for indoor positioning, as alternative to GNSS positioning. IBN allows to obtain a sub-metrical accuracy, but a special database of georeferenced images (DB) is needed, moreover it is necessary to use dedicated algorithm to resizing the images which are collected by smartphone, in order to share it with the server where is stored the DB. Moreover, it is necessary to characterize smartphone camera lens in terms of focal length and lens distortions. The Authors have developed an innovative method with respect to those available today, which has been tested in a covered area, adopting a special support where all sensors under testing have been installed. Geomatic instrument have been used to define the reference trajectory, with purpose to compare this one, with the path obtained with IBN solution. First results leads to have an horizontal and vertical accuracies better than 60 cm, respect to the reference trajectories. IBN method, sensors, test and result will be described in the paper

Il posizionamento indoor con smartphone, per la navigazione in una realtà smart-city

Oggigiorno la ricerca di punti di interesse è ormai parte integrante della nostra vita quotidiana, in particolare da quando la tecnologia smartphone si sta sempre più diffondendo nell’utenza mass market. Pur non essendo esperti di posizionamento o di geomatica, ogni utente può disporre in maniera molto semplice di un insieme molto complesso e concentrato di tecnologie e sensori per il posizionamento e la navigazione. Accelerometri, giroscopi, magnetometri, sensori di pressione, ricevitori GNSS, videocamere sono tutti validi strumenti per determinare la nostra posizione in maniera tridimensionale, e nella loro integrazione si trova il punto di forza di questo tipo di tecnologia

Unmanned aerial systems for data acquisitions in disaster management applications

The potentiality of the Unmanned Aerial Vehicle (UAV) has already been proved by the military community, which has employed aircrafts without men on-board for reconnaissance missions and attack operations in the enemy field. The technological progress in the electronic and aerospace engineering fields allowed the development of low-cost UAVs characterized by a small size (mini-UAVs) and low weight, that can carry on-board imaging or non-imaging sensors. These advantageous features led the civil community to have an increasing interest in mini-UAVs. The excellent flight performances, the suitability for various types of missions, the inexpensiveness, and the capability to carry on-board different sensors, allow mini-UAVs to be employed in various missions. Nowadays, these systems allow to carry out missions in the following fields: land monitoring, remote sensing, agriculture and public security. Also the photogrammetric community has taken part to the research issues concerning the use of UAVs for map production. The research group of Geomatics of the Politecnico di Torino has developed a set of interchangeable pods that can be mounted on a mini-UAV (a Hexacopter by Mikrokopter) devoted to emergency management in case of environmental disasters.This instrument is a low-cost mini-UAV equipped with photogrammetric sensors and capable of autonomous navigation (real time GNSS/IMU) and automatic digital image acquisition (characterized by a suitable geometric and radiometric quality). The platform is easily transportable on normal aircrafts and usable on the field, autonomously, by a couple of operators. The main innovation is to permits a real direct photogrammetric surveys in remote and disaster-affected areas in a short-range operative zone where it is not possible to carry out traditional photogrammetric flights. The acquisition technique allows the update of existing maps. Nevertheless, some test flights and practical applications have been performed in order to assess the autonomous flight performances and the suitability for photogrammetric flights

Co-registration of multitemporal UAV image datasets for monitoring applications : a new approach

n the last years we have witnessed a rapid development of UAVs (Unmanned Aerial Vehicles), especially for image collection. One of the advantages is the possibility to perform high resolution and repeated flights in a cheap way to detect changes over time. Thus, dynamic scenes can be monitored acquiring image blocks in different epochs in a flexible way. Anyway, most of UAVs are not able to provide accurate direct geo-referencing information, so image blocks from different epochs still need to be co-registered to efficiently detect changes. This task is mostly completed using GCPs (Ground Control Points), although this approach is time consuming as manual intervention is needed. This paper aims at investigating new techniques to automate the co-registration of image blocks without the use of GCPs, just relying on an image based co-registration (IBCR) approach. The image alignment is initially performed on a reference (anchor) epoch and the registration of the following (slave) epochs is performed including some (anchor) images from the reference epoch with fixed external orientation parameters. This allows constraining the Bundle Block Adjustment of the slave epoch to be consistent with the reference one. The study involved the use of 10 multi-temporal image block over a large building construction site, and spanning a time frame of 2 years. Different tests have been performed for the reference image choice with a manual approach and then evaluating the reached accuracy. The performed tests on the chosen test site have shown that the accuracy of the proposed methodology provides results comparable to the common GCPs registration approach