Thesis (Ph. D.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references.

No description available.

Accurately determining one’s location has long been a persistent problem in navigation and has reappeared in recent years in the field of mobile computing. The ability to determine a device’s location indoors is needed for both automation and efficient communication in collaborative robotic and sensor networks. Technologies such as indoor GPS transmitters and Cricket have been employed, but have had limited success due to cost, accuracy, and power consumption. The Inertial Solution for Accurately Assessing location Coordinates (ISAAC) was developed as a means of filling this need without requiring infrastructure or expensive components to accurately determine position, inside or outside. ISAAC is based on modified six-degrees-of-freedom (6DOF) dead reckoning algorithms currently being used by Unmanned Aerial Vehicles (UAV). UAVs typically have access to other types of sensors to supplement and/or replace the IMU measurements. ISAAC was implemented using a low-cost MEMS 6DOF IMU in which the onboard firmware was modified to incorporate the dead reckoning calculations and communications necessary to realize ISAAC. ISAAC was implemented as a portable unit which communicated with a host computer through an RS-232 interface. ISAAC did not perform as well as expected; the location coordinates were very inconsistent with device movements and did not produce any useful data. The correct intermediate results of the calculations and subsequent review by a local subject-matter-expert implies that the source of the erroneous results lie with the accuracy and precision of the MEMS IMU. ISAAC presents a foundation for future work where more robust sensors and/or filtering can be used for further examination of inertial-based location systems. / text

Utilizing a Global Navigation Satellite System (GNSS) together with an Inertial Navigation System (INS) is today a common integration method to obtain a positioning solution for autonomous systems. Both GNSS and INS have benefits and weaknesses where the best parts from both systems can be combined with a Kalman filter. Because of this complementary nature, it is of interest to look at the robustness of the positioning solution when the Global Navigation Satellite System is temporarily not available. The aim of the thesis has been to investigate different vehicle models and to evaluate their short-time performance using a Dead Reckoning approach. The goal has been to develop a system for a Heavy Duty Vehicle (HDV) and to find out for which time interval a specific model can stay within a certain range when the GNSS is lost. A GNSS outage could for example happen when driving on a highway and passing signs, bridges and especially when driving inside tunnels. Also, for a solution to become commercially interesting, it must be cheap. Therefore, is it common to use so called Micro-Electro-Mechanical-Systems (MEMS) sensors which are of low-cost but suffer from biases, scale factors and temperature dependencies which must be compensated for. The results from the tests show that some models are able to estimate the position with good precision during short time GNSS outages whereas other models do not deliver the required accuracy. The main conclusion is that care should be taken when choosing the vehicle model so that it fits its usage area and the complexity needed to describe its motion. There are also lots of parameters to look at when investigating the best solution, where modeling of the low-cost sensors is one of them.

Thesis(M.S.)--Auburn University, 2005. / Abstract. Includes bibliographic references.

国立情報学研究所で電子化したコンテンツを使用している。

<p>Denna rapport handlar om dead reckoning i bilspel. En rad nätverkstekniker tas upp grundligt, och fem olika versioner av dead reckoning implementeras, provkörs och utvärderas. En nätverkssimulator har skapats för att provköra algoritmerna i och datan från dessa provkörningar ligger till grunden för en analys av de olika implementationerna. De testas bland annat mot konsistens och bandbreddsåtgång. SimBins GTR Evolution har använts för att spela in loppen, och rapporten inriktar sig på hur dead reckoning fungerar i detta spel.</p>

Denna rapport handlar om dead reckoning i bilspel. En rad nätverkstekniker tas upp grundligt, och fem olika versioner av dead reckoning implementeras, provkörs och utvärderas. En nätverkssimulator har skapats för att provköra algoritmerna i och datan från dessa provkörningar ligger till grunden för en analys av de olika implementationerna. De testas bland annat mot konsistens och bandbreddsåtgång. SimBins GTR Evolution har använts för att spela in loppen, och rapporten inriktar sig på hur dead reckoning fungerar i detta spel.

In this thesis fundamental pieces of multi robot systems have been discussed and researched, in order to develop and build a system with easily obtainable electronics and to answer how much communication is needed as well as which design choices are important to make it robust. Our work will hopefully contribute to others in the community who are working with Raspberry Pi and Windows 10 IoT Core by being open source. As a result a proof of concept system of two simple robots has been implemented. In this paper we have used trigonometry and dead-reckoning for localization, when coordinating our robots a leader/follower model has been applied. The communication has been developed using the AllJoyn framework to develop an interface that has IoT capabilities. The results show that our system has working communication and simulated localization, however the limitations in the hardware results in an error in localization which we present in this paper. To answer our research questions the amount of communication needed is dependent on the problem and how many robots you need to apply in order to solve it and the most important design choice for current multi robot systems is a controlled environment.

Autonomous Underwater Vehicles (AUVs) are currently being used for many underwater tasks such as mapping underwater terrain, detection of underwater objects, and assessment of water quality. Possible uses continue to grow as the vehicles become smaller, more agile, and less expensive to operate. However, trade-offs exist between making less expensive, miniature AUVs and the quality at which they perform. One area affected by cost and size is the onboard navigation system. To achieve the challenges of low-cost rate sensors, this thesis examines calibration methods that are suitable for identifying calibration coefficients in low-cost MEMS gyros. A brief introduction to underwater navigation is presented and is followed by the development of a model to describe the operation of a rate gyro. The model uses the integral relationship between angular rate and angular position measurements. A compass and two tilt sensors provide calibrated angular position data against which the three single axis gyros are compared to obtain an error signal describing errors present in the angular rate measurements. A calibration routine that adaptively identifies error parameters in the gyros is developed. Update laws are chosen to recursively apply estimated error parameters to minimize the system error signal. Finally, this calibration method is applied to a simple dead reckoning algorithm in an attempt to measure the improvements calibration provides. / Master of Science