Navigation applications

Transcription

1 Navigation applications Academic Year 2007/08 Master of Science in Computer Engineering, Environmental and Land Planning Engineering

2 Car navigation

3 Car navigation It is possible to distinguish the two lines of march Train path reconstruction (different accuracy)

4 Car navigation GPS ebontek TomTom portable car navigator BluTooth connection Palmtop PC GIS (es. ArcPad) WebGIS (map server)

5 Traffic control In addition to the navigation of the single vehicle, the navigation information can be exploited to control the car traffic (and in general the road transportation, ITS). Interdisciplinary subject: numerical cartography (GIS) telematics operative research (to optimize paths, etc.)

6 Pedestrian navigation Conventional GPS only used for OUTDOOR applications The INDOOR use of GPS (when it works), or in the presence of many obstacles, does not assure a sufficient accuracy. Auxilary sensors are needed

7 RFID It is a presence/transit detector. Main advantages as compared to bar codes: it can be detected even if it is not visible identification and check are done in 10/100 of seconds RFID scanner RFID tag

8 Pseudolites The PSEUDOLITE (pseudo-satellite) is a GPS transmitter that is installed on ground in a stable way. The signal emitted by pseudolites emulates the one emitted by satellites, thus allowing an accurate and reliable localization in difficult environments, such as urban canyons or indoor environments.

9 Geodetic navigation The goal of geodetic navigation is NOT the navigation itself (position, velocity and attitude of a vehicle) BUT the vehicle is used as a moving geodetic platform for other sensors, which are then geo-referenced. The real-time processing is sometimes useful, but it is not essential as in the case of vehicle control. The a-posteriori processing allows to compute the optimal trajectory.

10 Mobile mapping Multi-sensor systems that lodge (integrate) on a single platform a navigation/positioning system with various data-acquisition systems Structural components Positioning system: GPS, Inertial Unit, Odometer, etc. Sensors: cameras (B/W, RGB, IR); laser scanner; sensors to measure the pollution level, the resistance of road pavement, etc. Systems for data acquisition, storage and synchronization. mobile platform navigation sensors image/signal sensors products GIS data digital maps images, videos

11 Mobile mapping Platforms: - Road vehicles, typically vans - Railway vehicles - Aircrafts (airplanes and helicopters) Motivations behind MM development - GPS diffusion, falling in price of INS - GIS diffusion Perspectives: autonomous vehicles navigation

12 Mobile mapping GPS / INS Odometer: Basically it is a revolution counter to compute the covered distance

13 Mobile mapping

14 Mobile mapping City navigation: - road cadastre, large-scale cartography - structure localization / street furniture / etc. Pavement control 2007 Applanix Corp., All Rights Reserved

15 Mobile mapping Railway applications: tunnel control, level crossing check, railway traffic management, etc. Optical system for rail survey 2007 Applanix Corp., All Rights Reserved

16 Mobile mapping Marine applications: bathymetry, pipe control, oil explorations Bathymetry obtained by sonar (Los Angeles) 2007 Applanix Corp., All Rights Reserved

17 Mobile mapping Aircraft applications: laser scanning (LIDAR), aerial photogrammetry, radar altimetry, SAR

18 LIDAR It is a distance-meter system mounted on an airplane/helicopter or on a ground vehicle or placed in a motionless location. Typically, mobile mapping by LIDAR is referred only to surveys on ground level; however its principle can be applied in general sense.

19 LIDAR Multiple reflection For a flying height of the order of 800 m, the vertical accuracy is about of 15 cm, while in planimetry it is about 30 cm. It can be used for - DTM / DSM separation - recognition of objects on ground

20 Earth s gravitation field determination from satellite A satellite orbiting the Earth can be considered as a proof-mass under the action of the Earth s gravitational field. If the satellite orbit is known, from this orbit it is possible to derive the Earth s gravitational potential. Problems: the satellite can be tracked from ground for short time-periods on board GPS for orbit determination the effect of the gravity is more significant at low altitude, where the atmospheric drag is higher. on board accelerometers to measure friction forces

21 Earth s gravitation field determination from satellite With the development of GPS receivers dedicated to geodetic satellites and of accelerometers with very high precision (~10-11 m/s 2 ), three satellite missions have been designed: CHAMP / GRACE / GOCE

22 Navigation and guidance Geodetic navigation Classic navigation positioning and orientation of a sensor on board a moving vehicle real time control of the trajectory and vehicle guidance Civil aviation: e.g. automatic pilot Military aviation: e.g. missile guidance

23 Navigation and robotics The autonomous navigation is closely related to robotics, in the sense that, apart from positioning and real-time guidance, concepts of artificial intelligence (e.g. computer vision) and mechanical engineering are required. The Grand Challenge is a competition organized by Darpa (Defense Advanced Research Projects Agency) among various research centres and universities for the development of unmanned vehicles. The navigation of the winner vehicle was based on six laserscanner (others were based on digital cameras), GPS systems, odometers, etc. Stanford Volkswagen Tuareg Stanley

24 Navigation and robotics A project has been studied for the development of a navigation software for an automatic lawn-mower for a golf course.