This master thesis studies distributed navigation which isa function implemented in a future network based combat information system to improve the accuracy in navigation for combat vehicles in a mechanized battalion, above all in the event of loss of GPS. In the event of loss of the GPS the vehicles obtain dead reckoning performance through the backup system that consists of an odometer and a magnetic compass. Dead reckoning means a drift in the position that makes the accuracy in the navigation worse. The distributed navigation function uses position and navigation data with measurements between the vehicles to estimate the errors and uncertainties in positions, which are used to improve the accuracy in position for the vehicles. To investigate and demonstrate distributed navigation, a simulation environment has been produced in Matlab. The environment is general so different navigation systems can be used and studied and also dynamical so a further development is possible. The simulation environment has been used to investigate and evaluate an implementation of distributed navigation. The implementation has been made using a central filter where fusion takes place of all navigation data and measurements. This filter has been realized with help of Kalman filter theory, in which all vehicles are put together in a state space model. Simulations have been performed for different scenarios and the result of these show that the drift in position is avoided.

Simultaneous Localization and Mapping (SLAM) is a technique used by robots and autonomous vehicles to build up a map while operating in an unknown environment, while at the same time keeping track of a current position estimate. This process is not as straightforward as it may sound. Due to inherent uncertainties in tracking the robot's motion and observing the world around it, errors accumulate. Incorporating External Localization (EL) sensors, such as Global Positioning System (GPS) receivers, which are not subject to the same type of drift over time, can allow a system to eliminate errors from the SLAM process. This, however, requires the system to work with measurements from both the SLAM and EL coordinate frames. Since the SLAM coordinate origin is dependent upon the vehicle's starting location, which is unknown, the relationship between it and the EL frame is unknown and must be estimated. The main contributions of this thesis arise from a novel approach to integrating EL with SLAM, by estimating a transformation between the SLAM and external reference frames. The Constrained Relative Submap Filter (CRSF) SLAM is a computationally efficient SLAM lter operates on a series of local submaps, instead of one large map, as with Extended Kalman Filter (EKF) SLAM. By integrating the transformation estimation process with CRSF SLAM, a method to correct submap locations with EL is presented. This eliminates long term estimation drift, aids in loop closing and allows for accurate map generation with a reference to an external frame.

Understanding human spatial cognition and behaviour is not something easily studied. Many factors are involved that contribute in different ways for different individuals. Navigation and wayfinding have been used as an approach, or starting point, for such studies. Spatial abilities tests have long been used as reference points to generalize to overt navigational behaviour. Care needs to be taken in generalizing from paper to behaviour to make certain that it is a valid relationship exists.<p>The purpose of this study was to examine the extent to which certain psychometric spatial abilities tests are indicators of actual navigational decision making. The study was conducted in two phases. The navigational decision tasks were made up of four paths with two variables: length and number of turns. The participants were required to make a decision on which direction to go after being lead part of the way around a hallway. The choices were to either go back the way they were led or take a novel route along a previously un-travelled path (shortcut). Spatial abilities tests (MRT, PFT, and OLMT), a self-rating of SOD, and learning preference for novel environments were administered in phase two. <p>While efficient navigation was not explicitly required in the navigation tasks those participants making the most efficient decisions shared similar characteristics. Efficient navigators have a higher aptitude for mental manipulation (as measured by the MRT), express a preference for a more exploratory environmental learning style, are disproportionately male, and have a slightly higher self-rating of SOD. In addition to the collective set of four navigation decisions (one for each experimental path), path 2 demonstrated the efficient vs. non-efficient distinction quite well: in order to make the most efficient decision the individual must maintain the correct metric distance from the origin point and not be deterred by the passage of only half of the turns in the rectangular experimental environment.

In 1587, an ambitious colonial bureaucrat in Mexico City published a handbook titled Instrucción náutica. Although navigational books were common throughout the 16th century, the Instrucción náutica was the first printed volume that included an extensive discussion of ship construction and design, and its publication was thus a significant event in the history of early modern nautical technology. While the work is frequently cited in discussions of 16th-century Spanish ship construction and seafaring, little in-depth analysis of the text has been undertaken to verify its accuracy. In order to understand the significance of the book, a critical evaluation was undertaken of its context and content and of the motivations and background of its author. Analysis of documents written by, about, and to Diego García de Palacio reveals that he held positions of academic, religious, and political power in New Spain, that his motives for publishing the book were complex, and that he consulted a range of disparate sources. Significantly, archival correspondence suggests that García de Palacio was an observer and administrator of navigation and ship construction, rather than an expert practitioner. Nonetheless, comparison of the technical content of the book with other sources of information for 16th-century ships and seafaring, including contemporary treatises, iconography, and archaeological materials confirms the overall accuracy of the text. The navigational materials included in the Instrucción náutica reflect information adapted from existing texts, providing a solid overview of the most common techniques of navigation in use at the time. While useful, García de Palacio’s discussion of ship design was clearly intended for a non-specialist audience. Perhaps the most original technical contributions are his descriptions of the rigging of Spanish ships. The brief discussion of naval strategy is historically significant due to its juxtaposition between the last of the great naval battles fought primarily with boarding tactics, and the movement toward increasing reliance on the broadside. By comparing García de Palacio’s text to other sources of information, this study has confirmed the reputation of the Instrucción náutica as one of the most comprehensive and accurate written descriptions of 16th-century Spanish seafaring practices.

Autonomous robots can replace humans to explore hostile areas, such as Mars and other inhospitable regions. A fundamental task for the autonomous robot is navigation. Due to the inherent difficulties in understanding natural objects and changing environments, navigation for unstructured environments, such as natural environments, has largely unsolved problems. However, navigation for ill-structured environments [1], where roads do not disappear completely, increases the understanding of these difficulties. We develop algorithms for robot navigation on ill-structured roads with monocular vision based on two elements: the appearance information and the geometric information. The fundamental problem of the appearance information-based navigation is road presentation. We propose a new type of road description, a vision vector space (V2-Space), which is a set of local collision-free directions in image space. We report how the V2-Space is constructed and how the V2-Space can be used to incorporate vehicle kinematic, dynamic, and time-delay constraints in motion planning. Failures occur due to the limitations of the appearance information-based navigation, such as a lack of geometric information. We expand the research to include consideration of geometric information. We present the vision-based navigation system using the geometric information. To compute depth with monocular vision, we use images obtained from different camera perspectives during robot navigation. For any given image pair, the depth error in regions close to the camera baseline can be excessively large. This degenerated region is named untrusted area, which could lead to collisions. We analyze how the untrusted areas are distributed on the road plane and predict them accordingly before the robot makes its move. We propose an algorithm to assist the robot in avoiding the untrusted area by selecting optimal locations to take frames while navigating. Experiments show that the algorithm can significantly reduce the depth error and hence reduce the risk of collisions. Although this approach is developed for monocular vision, it can be applied to multiple cameras to control the depth error. The concept of an untrusted area can be applied to 3D reconstruction with a two-view approach.

When evaluating the benefits of the artificial reefs, the generally is performed by sending divers or using Remotely Operated Vehicles (ROV). But to do the observation work, the deep sea is too dangerous for human being to work longer time, and ROV has no capable navigation system. So underwater survey became difficulty. The thesis integrates LXT Tracking System, Global Positioning System, Motion Sensor, Gyro Compass and the ROV original sensors such as : pressure sensor and magnetic compass to resolve the navigation problem of ROV, together with the high-density data of Multibeam echo sounder to rebuild the status of the seabed and artificial reefs. The thesis tries to apply the technology of Virtual Reality (VR) in ROV to being the interface. The results demonstrate the VR interface can display the position of ROV in three-dimensional space actually. And it can show the position of ROV navigation and warning message in real time when sailing. So the VR Navigation System will improve the ability of operating ROV greatly.

On 30 December 1986, a local fisherman incidentally discovered the remains of a seventeenth-century merchantman off the coast of Rincon, a small municipality on Puerto Rico's west coast. Some days later, he and some acquaintances extracted objects from the site and stored them in a nearby restaurant. The assemblage of artifacts recovered included, among other items, pins, scissors, ordnance, pewter ware, woodworking tools, a myriad of concretions and a nautical astrolabe. It is from the last that the wreck site took its name. The operation continued for months until local authorities, alerted by a member of the salvage group, issued a cease and desist order. At that point, the whole affair entered a legal process that on the summer of 2005 had not reached its conclusion. The purpose of this thesis is twofold. First, the author presents the story of the shipwreck from the moment it was found until the court ruled regarding ownership of the artifacts. Since this was the first time ownership of a shipwreck was debated in Puerto Rican courts in recent history, this gives the reader an idea of how legal precedence was established concerning the island's submerged cultural resources. Second, based on what was popularly perceived to be the site's most remarkable find, a study was developed on the sea or mariner's astrolabe, a navigation instrument that played a fundamental role in the process of European maritime expansion during the late fifteenth, sixteenth and seventeenth centuries. The reader of this text will learn that, during the fifteenth century, Portuguese navigators saw the need to gradually depart from the traditional Mediterranean navigation technique known as "dead reckoning." As their explorations along the West African coast forced them to sail far into the Atlantic Ocean for prolonged periods, a new method was developed that consisted of measuring the angle of certain heavenly bodies above the horizon in order to determine the latitude of the observer with reasonable precision. For this purpose, instruments that traditionally belonged to the field of astronomy were adapted to be used by seamen. Among them was the astrolabe, which became the most popular by the turn of the sixteenth century. After discussing the instrument's origin and development, the author analyzes how a renewed interest on the nautical astrolabe, which emerged in Portugal in the early twentieth century, introduced the instrument to the field of modern scholarly research. This work also presents a catalogue of sixteen sea astrolabes, some of which have never been published. The catalogue shows statistics and other relevant information, while placing the artifacts in the context of the previously existing data.

<p> </p><p>Datoriseringen ökar exponentiellt i dagsläget och har gjort de senaste tre decennierna. Med denna utveckling så ökar även näthandeln eftersom detta är viktigt för att kunna konkurrera med andra detaljvaruförsäljare. Till varje webbshop så finns det en administrationsapplikation där webbshopsägaren sköter webbshopen. Problem som kan uppstå i dessa gränssnitt kan vara så kallade kognitiva arbetsmiljöproblem vilket kommer att undersökas i detta arbete för att se hur de kan påverka navigationen specifikt. En prototyp skapades för att lösa dessa kognitiva arbetsmiljöproblem med hjälp av välkända designriktlinjer. I en användbarhetsundersökning så visade det sig att den nya prototypen faktiskt löser dessa problem men en ny prototyp skapades i efterhand där två nya designelement tillagts efter förslag från användbarhetstestdeltagarna.</p><p> </p>

<p>Saab Bofors Dynamics har som huvudsaklig verksamhet att utveckla missiler. Ofta krävs det att någon form av navigationsfunktion byggs in, och eftersom det inte är lätt att testa nya lösningar och algoritmer direkt på missilerna har man tagit fram två autonoma testplattformar, Freke och Gorm, i form av självgående bilar som kan ta sig fram inomhus i t.ex. en korridor.</p><p>För navigation utomhus lämpar sig GPS väl i många situationer, men i autonoma sammanhang är det inte tillräckligt. GPS är inte alltid tillgänglig på grund av att man inte alltid har fri sikt till minst fyra satelliter och i militära sammanhang är den också lätt att störa ut. Därför förlitar man sig hellre på noggranna tröghetsnavigeringssystem (TNS) som kan ge data i 100-tals Hz, och kompletterar med GPS för att korrigera för avvikelser. Oftast integrerar man sensorerna med någon form av Kalmanfilter för att kunna skatta felparametrar. Om GPS:en faller ifrån kan man med hjälp av felparametrarna navigera noggrannare med ett TNS än man skulle ha gjort annars</p><p>Noggranna TNS är dock både relativt stora och dyra. Referenssystem kan kosta uppåt en miljon kronor, och lämpar sig alltså varken för engångsbruk (i missiler) eller små billiga autonoma bilar. Nu finns det små och relativt billiga tröghetssensorer (IMU, Inertial Measurement Unit) som storleksmässigt lämpar sig väldigt väl, men som dock har ganska låg noggrannhet.</p><p>I detta examensarbete görs en studie av två olika navigationsmodeller där en billig IMU och en GPS integreras med hjälp av ett Extended Kalmanfilter (EKF).</p>

<p>This master thesis studies distributed navigation which isa function implemented in a future network based combat information system to improve the accuracy in navigation for combat vehicles in a mechanized battalion, above all in the event of loss of GPS. In the event of loss of the GPS the vehicles obtain dead reckoning performance through the backup system that consists of an odometer and a magnetic compass. Dead reckoning means a drift in the position that makes the accuracy in the navigation worse. </p><p>The distributed navigation function uses position and navigation data with measurements between the vehicles to estimate the errors and uncertainties in positions, which are used to improve the accuracy in position for the vehicles. </p><p>To investigate and demonstrate distributed navigation, a simulation environment has been produced in Matlab. The environment is general so different navigation systems can be used and studied and also dynamical so a further development is possible. </p><p>The simulation environment has been used to investigate and evaluate an implementation of distributed navigation. The implementation has been made using a central filter where fusion takes place of all navigation data and measurements. This filter has been realized with help of Kalman filter theory, in which all vehicles are put together in a state space model. Simulations have been performed for different scenarios and the result of these show that the drift in position is avoided.</p>