Suchergebnisse

Parts 3-5, 7, reproduced from type-written copy. ; pt. 1.--Introduction to earth.--pt. 2. Introduction to navigation.--pt. 3. Dead reckoning and lines of position.--pt. 4. Navigation instruments.--pt. 5. Relative movement.--pt. 6. Contact flying.--pt. 7. Nautical astronomy and celestial navigation. ; Mode of access: Internet.

Robotter vil om få år blive en del af vores daglige liv. Inden for produktionsindustrien har det allerede være tilfældet i mange år, men anvendelsen af mobile robotter har hidtil været henvist til isolerede områder som græsslåning, overvågning, landbrugsproduktion og militære funktioner. Fremskridt i forskningen gør, at robotter vil kunne assistere os i mange af vore daglige gøremål i en ikke så fjern fremtid. En af de teknologier, der skal gøre dette muligt, er navigation, og navigation er emnet for denne afhandling. Navigation for autonome robotter handler om robottens evne til autonomt at manøvrere fra den nuværende position til et ønsket bestemmelsessted. Denne afhandling præsenterer og validerer eksperimentelt løsninger til detektering af farbar vej, omgåelse af forhindringer og gennemførelse af missioner. Vejklassifikationen er baseret på laserscanner-målinger og assisteret med vision for længere rækkevidde. Vejklassifikationen er tilstrækkelig selektiv til at kunne adskille selv flade vejrabatter fra selve vejen og kan isolere asfaltveje fra grusveje. Vejgenkendelse ud fra kamerabilleder tager udgangspunkt i klassifikationen fra laserscanneren og bruger en kombination af farve og kantdetektering til at estimere farbar vej på længere afstande. Resultatet af disse to sensorer anvendes under planlægning af en farbar rute, og her er det især robottens evne til at følge vejens kanter, der er undersøgt. Navigationen i en mission er styret af et sekventielt manuskript. Manuskriptsproget giver mulighed for detektering af vejkryds, for beregninger til brug under passagen af disse kryds og til valg a styringsmetode i øvrigt. Det samlede system er testet på en kombination af asfalt- og grusveje, med et antal forgreninger og vejkryds. Missioner på op til 3km længde er gennemkørt autonomt med det beskrevne system. Fokus i afhandlingen har været den eksperimentelle validering af de implementerede metoder og metodernes evne til at løse problemer i en virkelig verden. Der skal en betydelig mængde software til for at styre en autonom robot, emner som software genbrug og distribueret udvikling er derfor essentielle. Denne afhandling beskriver yderligere en komponentbaseret arkitektur for robotter, som kan fremme software genbrug og distribueret udvikling og vedligeholdelse. ; Abstract Robots will soon take part in everyone's daily life. In industrial production this has been the case for many years, but up to now the use of mobile robots has been limited to a few and isolated applications like lawn mowing, surveillance, agricultural production and military applications. The research is now progressing towards autonomous robots which will be able to assist us in our daily life. One of the enabling technologies is navigation, and navigation is the subject of this thesis. Navigation of an autonomous robot is concerned with the ability of the robot to direct itself from the current position to a desired destination. This thesis presents and experimentally validates solutions for road classification, obstacle avoidance and mission execution. The road classification is based on laser scanner measurements and supported at longer ranges by vision. The road classification is sufficiently sensitive to separate the road from flat roadsides, and to distinguish asphalt roads from gravelled roads. The vision-based road detection uses a combination of chromaticity and edge detection to outline the traversable part of the road based on a laser scanner classified sample area. The perception of these two sensors are utilised by a path planner to allow a number of drive modes, and especially the ability to follow road edges are investigated. The navigation mission is controlled by a script language. The navigation script controls route sequencing, junction detection, junction crossing calculations and drive mode selection. The entire system is tested on a combination of narrow asphalt and gravelled roads connected by a number of junctions. Missions of up to 3km in length have been successfully completed using the described system. The main focus of the thesis has been the experimental validation of the implemented solutions and the ability of the methods to solve real world problems. The amount of software needed by an autonomous robot can be overwhelming. Software reuse and distributed development are therefore important issues. The thesis describes a new component architecture for robotics software that promotes software reuse and distributed development and maintenance.

In the case of one car following another to a destination, it is very effective at getting the second vehicle to the destination quickly; however, the driver of the second car may not learn the route. Yet, for individuals, such as firefighters, law enforcement, and military personnel, it is imperative that a route be learned quickly and accurately and that an awareness of the situation is maintained while they traverse the given route. This leads to three questions, (a) will navigation aids affect initial route navigation; (b) will navigation aids affect retention; and (c) will navigation aids affect situation awareness while en route? The hypotheses of this study were that navigation aids would significantly increase the speed at which a person can initially navigate a route, but the use of the aids would significantly decrease the retention of the route navigated. The findings of this study support the hypotheses. The results suggest that participants that followed a confederate and participants that were given verbal directions were quicker and made fewer errors than participants that reviewed a map or initially figured the route out on their own (control group). The study also showed that as the participants navigated the route for a second time with no navigational assistance, the ones that reviewed a map or that were in the control group outperformed participants that initially had a confederate to follow or were given verbal directions their first time through. Finally, no real effects were found on the participants' situation awareness during the retention portion of the study. ; 2005-05-01 ; Ph.D. ; Engineering and Computer Science, Other ; Doctorate ; This record was generated from author submitted information.

Published also in French. ; Title taken from portfolio. ; In portfolio. ; At head of title: Permanent International Association of Navigation Congresses. X. Congress--Milan, 1905. ; 1. Rapid increase in the dimensions of steamers and sailing vessels. Draught of water of these. Effect of the increase on the harbours, canals and approaches. 4 v.--2. The use of liquid fuel for purposes of navigation. 2 v.--3. The transport of cargo by "ferryboats". 4 v.--4. Report of the most recent works carried out in the principal seaports. 13 v.--5. Responsibility of ship owners in regard to private parties or public administrations. 3 v.--6. Coast signals, lightships, wireless telegraphy. 5 v.--7. Measures adopted by the different governments for the protection of ocean navigation. Bounties, reduced railway tariffs for merchandise intended to be transported by sea. 5 v. ; Mode of access: Internet.

The history of legislation in Illinois in regard to canals, including the present scheme for a drainage ship canal.--The story of the Erie Canal. ; Mode of access: Internet.

The precision navigation capabilities of the Global Positioning System (GPS) are used extensively within US military operations. However, GPS is highly vulnerable to intentional and unintentional external interference. Therefore, a need exists to develop a non-GPS precision navigation method to operate in GPS degraded environments. This research effort presents the theoretical limits of a precision navigation method based on an inertial navigation system (INS) aided by angle measurements with respect to lunar surface features observed by a fixed camera. To accomplish this task, an extended Kalman filter (EKF) was implemented to estimate INS drift errors and bring in simulated lunar feature angle measurements to correct error estimates. The research scope focused solely on the feasibility of lunar vision aided navigation with INS where only measurement noise effects from a simulated CCD camera and barometer were considered. Various scenarios based on camera specifications, lunar feature quantity, INS grade, and lunar orbital parameters were conducted to observe the INS drift correction by lunar feature angle measurements. The resulting trade spaces presented by the scenarios showed theoretical substantial improvement in the navigation solution with respect to a stand alone INS.

Bureau Veritas has an interest in expanding the Guidelines for 'Ice Reinforcement Selection in Different World Navigation Areas' to include a chapter on Greenland Waters. This report contains the chapter for the guidelines and includes: 1) typical ice conditions, 2) selection of appropriate ice class, 3) legislation to be followed and 4) additional interesting meteorological parameters. A short supplement is included that provides further detail on source data and methods. ; NRC publication: Yes

Modules / Lectures : Navigation ; Continuous Wave and Frequency Modulated Radars ; MTI and Pulse Doppler Radars ; Guided Missiles ; Missile Guidance Laws ; Aircraft Navigation ; Control Systems ; Frequency Response of Linear Systems ; State variable Analysis of Linear Systems

This work presents a novel navigation system for social collaborative virtual environments populated with multiple characters. The navigation system ensures collision free movement of avatars and agents. It supports direct user manipulation, automated path planning, positioning to get seated, and follow-me behaviour for groups. In follow-me mode, the socially aware system manages the mise en place of individuals within a group. A use case centred around on an educational virtual trip to the European Parliament created for the REVERIE FP7 project, also serves as an example to bring forward aspects of such navigational requirements.

International audience ; Advancements in mobile technology and computing have fostered the collection of a large number of civic datasets that capture the pulse of urban life. Furthermore, the open government and data initiative has led many local authorities to make these datasets publicly available, hoping to drive innovation that will further improve the quality of life for the city dwellers. In this paper, we develop a novel application that utilizes crime data to provide safe urban navigation. Given a model that allows us to estimate the relative probability of a crime on any road segment, we define two variants of the SafePaths problem where the goal is to find a short and low-risk path between a source and a destination locations. Since both the length and the risk of the path are equally important and they cannot be combined into a single objective, we approach the urban-navigation problemas a biobjective shortest path problem. Our algorithms aim to output a small set of paths that provide tradeoffs between distance and safety. While the solution space of such biobjective problems can be exponentially large, we design efficient algorithms that effectively exploit its structure and geometry. We enhance these algorithms with early-stopping criteria, which in practice lead to four times shorter running times with minimal sacrifices in the information content they provide to the user. In addition, using crime data from Chicago and Philadelphia we develop the required risk model for their street urban networks. Our experiments with this data demonstrate the efficacy of our algorithms and their practical applicability.

The INTERACT Fieldwork Communication and Navigation Guidebook, is published to help you choose relevant means of communication and navigation for your fieldwork in the Cold North and in mountain-ous regions. It gives advice on how to communicate during fieldwork, both through the different means of communication and at face-to-face fieldwork meetings. Finally, it looks to the future to foresee what improvements in relation to means of communication and navigation we can expect for tomorrow's fieldwork. The book has been made in cooperation between INTERACT, APECS and the managers of arctic and northern alpine research stations, with funding provided by the European Union through the Horizon 2020 Research and Innovation Programme.

Das Kopernikus-Projekt ENavi will der Komplexität des Energiesystems begegnen, indem es unterschiedliche disziplinäre und soziale Wissensbestände aus allen ENavi-Forschungsarbeiten zusammenführt. Damit dies gelingt, wird das Projektteam in dem Modul Roadsmap und Navigation energiepolitische Entscheidungen aus systemanalytischer Perspektive abschätzen und bewerten und so den Weg zu einem nachhaltigen Energiesystem aufzeigen.

Das Kopernikus-Projekt ENavi will der Komplexität des Energiesystems begegnen, indem es unterschiedliche disziplinare und soziale Wissensbestände aus allen ENavi- Forschungsarbeiten zusammenführt. Damit dies gelingt, wird das Projektteam in dem Modul Roads-map und Navigation energiepolitische Entscheidungen aus systemanalytischer Perspektive abschätzen und bewerten und so den Weg zu einem nachhaltigen Energiesystem ...

In this thesis a terrain positioning method for underwater vehicles called the correlation method is presented. Using the method the vehicle can determine its absolute position with the help of a sonar and a map of the bottom topography. The thesis is focused towards underwater positioning but most of the material is directly applicable to flying vehicles as well. The positioning of surface vehicles has been revolutionized by the global positioning system (GPS). However, since the GPS signal does not penetrate into the sea water volume, underwater vehicles still have to use the inertial navigation system (INS) for navigation. Terrain positioning is therefore a serious alternative to GPS for underwater vehicles for zeroing out the INS error in military applications. The thesis begins with a review of different estimation methods as Bayesian and extended Kalman filter methods that have been used for terrain navigation. Some other methods that may be used as the unscented Kalman filter or solving the Fokker-Planck equation using finite element methods are also discussed. The correlation method is then described and the well known problem with multiple terrain positions is discussed. It is shown that the risk of false positions decreases exponentially with the number of measurement beams. A simple hypothesis test of false peaks is presented. It is also shown that the likelihood function for the position under weak assumptions converges to a Gaussian probability density function when the number of measuring beams tends to infinity. The Cramér-Rao lower bound on the position error covariance is determined and it is shown that the proposed method achieves this bound asymptotically. The problem with measurement bias causing position bias is discussed and a simple method for removing the measurement bias is presented. By adjusting the footprint of the measuring sonar beams to the bottom topography a large increase in accuracy and robustness can be achieved in many bottom areas. This matter is discussed and a systematic ...

Navigation, defined as goal-related movement through space and time to reach a destination, is a fundamental human activity. Geographers, physiologists, archeologists, anthropologists, and psychologists have long been interested in the spatial, temporal, and energy expenditure aspects of navigation. Hikers, search and rescue teams, firefighters, the military, and others navigate on foot through rugged terrain, and their success depends on understanding how the dynamics of foot-based navigation affect individual capabilities, caloric requirements, and risk potential. This research project modeled energy expenditure and speed of movement of human beings engaged in foot-based navigation in wooded environments with varied terrain. The models were developed using spatiotemporal analysis of a subject's movement trajectories and biometrics. Energy expenditure estimates were collected via biosensors and Global Navigation Satellite Systems (GNSS) from subjects while they engaged in foot-based navigation through undeveloped, forested landscapes. Trajectory data from 200 subjects were merged with a land cover data set to analyze characteristics of human navigation over varying slopes and terrain. Generalizing these characteristics provided a model of energy expenditure and navigational speed from an origin to destination along an unknown route. The equation developed to model energy expenditure of a human's route during navigation uses terrain slope, land cover, body mass index (BMI), sex and traveled distance to predict Calorie consumption with an accuracy of 89 percent. The model of navigation speed accurately predicts route completion time within 10 percent. These models help to explain the human dynamics of navigation.