Darbo tikslas yra išanalizuoti keliaujančio pirklio algoritmo realizacijos galimybes egzistuojančiose navigacinėse sistemose, bei išanalizavus pasirinktus algoritmus keliaujančio pirklio problemai spręsti, parinkti tinkamiausią algoritmą pagal turimus atminties ir skaičiavimo resursus bei problemos sudėtingumą. Tyrimo rezultatai parodė, jog nėra tinkamiausio algoritmo visiems atvejams, nes skirtingose situacijose skirtingi algoritmai rodo geriausius rezultatus. / The investigation had a list of objectives: analyze the capabilities and resources of a range of chosen GPS navigation devices; analyze the needs and requirements of traveling salesman related GPS navigator functions for regular users; analyze what types of TSP algorithms are used in existing navigation software products; analyze the capabilities of various TSP algorithms with regard to used resources and speed of calculations; determine which algorithms are optimal for a range of specific situations. Research of different algorithms led to a conclusion that there is no single algorithm that is always better than the rest. Under different circumstances, different algorithms showed different results. Some were clearly optimal in some situations, while others competed with each other in other situations. The key element to success of an algorithm was how much time it got to do it's calculations. The amount of the input data changed the duration of the calculations but the algorithm function declination rate remained mostly the same with different sets of input data.

GPS has become very popular in recent years. It is used in wide range of applications including aircraft navigation, search and rescue, space borne attitude and position determination and cellular network synchronization. Each application places demands on GPS for various levels of accuracy, integrity, system availability and continuity of service. Radio frequency interference (RFI) which results from many sources such as TV/FM harmonics, radar or mobile satellite systems, presents a challenge to the use of GPS. It can affect all the service performance indices mentioned above. To improve the accuracy of GPS positioning, a continuously operating reference station (CORS) network can be used. A CORS network provides all the enabled GPS users in an area with corrections to the fundamental measurements, producing more precise positioning. A threat to these networks is a threat to all high-accuracy GPS users. It is therefore necessary to monitor the quality of the received signal with the objective of promptly detecting the presence of RFI and providing a timely warning of the degradation of system accuracy, thereby boosting the integrity of GPS. This research was focused on four main tasks: a) Detection. The focus here is on a power spectral density fluctuation detection technique, in which statistical inference is used to detect narrowband continuous-wave (CW) interference in the GPS signal band after being captured by the RF front-end. An optimal detector algorithm is proposed. At this optimal point, for a fixed Detection Threshold (DT), probability of false alarm becomes minimal and for a fixed probability of false alarm, we can achieve the minimum value for the detection threshold. Experiments show that at this point we have the minimum computational load. This theoretical result is supported by real experiments. Finally this algorithm is employed to detect a real GPS interference signal generated by a TV transmitter in Sydney. b) Characterization. In the characterization section, using the GNSS signal structure and the baseband signal processing inside the GNSS receiver, a closed formula is derived for the received signal quality in terms of effective carrier to noise ratio ( ). This formula is tested and proved by calculating the C/No using the I and Q data from a software GPS receiver. For pulsed CW, a similar analysis is done to characterize the effect of parameters such as pulse repetition period (PRP) and also duty cycle on the received signal quality. Considering this characterization and the commonality between the GPS C/A code and Galileo signal as a basis to build up a common term for satellite availability, the probability of satellite availability in the presence of CW interference is defined and for the two currently available satellite navigation systems (GPS L1 signal and Galileo signal (GIOVE-A BOC(1, 1) in the E1/L1 band)) it is shown that they can be considered as alternatives to each other in the presence of different RFI frequencies as their availability in the presence of CW RFI is different in terms of RFI frequency. c) Mitigation. The last section of the research presents a new concept of ?Satellite Exclusion Zone?. In this technique, using our previously developed characterization techniques, and considering the fact that RFI has different effects on different satellite signals at different times depending on satellite Doppler frequency, the idea of excluding the most vulnerable satellite signal from positioning calculations is proposed. Using real data and real interference, the effectiveness of this technique is proven and its performance analyzed. d) Hardware implementation. The above detection technique is implemented using the UNSW FPGA receiver board called NAMURU.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 206-216).

Thesis (M.S.)--Ohio University, June, 2000. / Title from PDF t.p.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references (p.84-85).

"Author biographies are available in the expanded on-line version of this article [http://www.insidegnss.com/auto/julyaug09-tetewsky-final.pdf]" / "July/August 2009." Web site title: Making Sense of GPS Inter-Signal Corrections : Satellite Calibration Parameters in Legacy and Modernized Ionosphere Correction Algorithms.

Navigation systems are today options provided by car manufacturers’ world wide and market predictions suggest that 25 percent of all cars produced by 2009 will have navigation systems installed. However, there are many human-interface issues concerning the use of these navigation systems. This thesis describes a study which evaluates and tests the safety and usability of the Volvo P1 navigation system and also contains suggestions on how the system and its controls should be designed to be safer and easier to use. This is done through heuristic evaluations and a Lane Change Test (LCT). The LCT is used to compare the level of driver distraction between the steering wheel control and remote control and also between common and advanced exercises in the system. Results from the study shows that there are no significant differences in distraction between using the steering wheel control or the remote control. The results also show that there are no significant differences in distraction between the common and advanced exercises. The results of the study are presented as a collection of design proposals that can be used to improve the system’s safety and usability.

No description available.

M.Ing. / The Graphics Processor Unit (GPU) has been in the gaming industry for several years now. Of late though programmers and scientists have started to use the parallel processing or stream processing capabilities of the GPU in general numerical applications. The Monte Carlo method is a processing intensive methods, as it evaluates systems with stochastic components. The stochastic components require several iterations of the systems to develop an idea of how the systems reacts to the stochastic inputs. The stream processing capabilities of GPUs are used for the analysis of such systems. Evaluating low-cost Inertial Measurement Units (IMU) for utilisation in Inertial Navigation Systems (INS) is a processing intensive process. The non-deterministic or stochastic error components of the IMUs output signal requires multiple simulation runs to properly evaluate the IMUs performance when applied as input to an INS. The GPU makes use of stream processing, which allows simultaneous execution of the same algorithm on multiple data sets. Accordingly Monte Carlo techniques are applied to create trajectories for multiple possible outputs of the INS based on stochastically varying inputs from the IMU. The processing power of the GPU allows simultaneous Monte Carlo analysis of several IMUs. Each IMU requires a sensor error model, which entails calibration of each IMU to obtain numerical values for the main error sources of lowcost IMUs namely scale factor, non-orthogonality, bias, random walk and white noise. Three low-cost MEMS IMUs was calibrated to obtain numerical values for their sensor error models. Simultaneous Monte Carlo analysis of each of the IMUs is then done on the GPU with a resulting circular error probability plot. The circular error probability indicates the accuracy and precision of each IMU relative to a reference trajectory and the other IMUs trajectories. Results obtained indicate the GPU to be an alternative processing platform, for large amounts of data, to that of the CPU. Monte Carlo simulations on the GPU was performed 200 % faster than Monte Carlo simulations on the CPU. Results obtained from the Monte Carlo simulations, indicated the Random Walk error to be the main source of error in low-cost IMUs. The CEP results was used to determine the e ect of the various error sources on the INS output.

L'éco-routage est une méthode de navigation du véhicule qui sélectionne les trajets vers une destination minimisant la consommation de carburant, la consommation d'énergie ou les émissions de polluants. C'est l'une des techniques qui tentent de réduire les coûts d'exploitation et l'empreinte environnementale du véhicule. Ce travail passe en revue les méthodes actuelles d'éco-routage et propose une nouvelle méthode pour pallier leurs insuffisances. La plupart des méthodes actuelles attribuent à chaque route du réseau routier un coût constant qui représente la consommation du véhicule ou la quantité de polluants émis. Un algorithme de routage optimal est ensuite utilisé pour trouver le chemin qui minimise la somme de ces coûts. Différentes extensions sont considérées dans la littérature. L'éco-routage contraint permet d'imposer des limites sur le temps de trajet, la consommation d'énergie et les émissions de polluants. L'éco-routage dépendant du temps permet le routage sur un graphique avec des coûts qui sont fonction du temps. L'éco-routage adaptatif permet de mettre à jour la solution d'éco-routage au cas où elle deviendrait invalide en raison d'un développement inattendu sur la route. Il existe des méthodes d'éco-routage optimales publiées qui résolvent l'éco-routage dépendant du temps ou l'éco-routage contraint ou l'éco-routage adaptatif. Chacun vient avec des frais généraux de calcul considérablement plus élevés par rapport à l'éco-routage standard et, à la connaissance de l'auteur, aucune méthode publiée ne prend en charge la combinaison des trois: éco-routage adaptatif dépendant du temps contraint. On soutient dans ce travail que les coûts d'acheminement sont incertains en raison de leur dépendance au trafic immédiat autour du véhicule, du comportement du conducteur et d'autres perturbations. Il est en outre soutenu que puisque ces coûts sont incertains, il y a peu d'avantages à utiliser un routage optimal car l'optimalité de la solution ne tient que tant que les coûts de routage sont corrects. Au lieu de cela, une méthode d'approximation est proposée dans ce travail. La charge de calcul est plus faible car la solution n'est pas requise pour être optimale. Cela permet l'éco-routage adaptatif dépendant du temps contraint. / Eco-routing is a vehicle navigation method that selects those paths to a destination that minimize fuel consumption, energy consumption or pollutant emissions. It is one of the techniques that attempt to lower vehicle's operational cost and environmental footprint. This work reviews the current eco-routing methods and proposes a new method designed to overcome their shortcomings. Most current methods assign every road in the road network some constant cost that represents either vehicle's consumption there or the amount of emitted pollutants. An optimal routing algorithm is then used to find the path that minimizes the sum of these costs. Various extensions are considered in the literature. Constrained eco-routing allows imposing limits on travel time, energy consumption, and pollutant emissions. Time-dependent eco-routing allows routing on a graph with costs that are functions of time. Adaptive eco-routing allows updating the eco-routing solution in case it becomes invalid due to some unexpected development on the road. There exist published optimal eco-routing methods that solve either the time-dependent eco-routing, or constrained eco-routing, or adaptive eco-routing. Each comes with considerably higher computational overhead with respect to the standard eco-routing and, to author's best knowledge, no published method supports the combination of all three: constrained time-dependent adaptive eco-routing. It is argued in this work that the routing costs are uncertain because of their dependence on immediate traffic around the vehicle, on driver's behavior, and other perturbations. It is further argued that since these costs are uncertain, there is little benefit in using optimal routing because the optimality of the solution holds only as long as the routing costs are correct. Instead, an approximation method is proposed in this work. The computational overhead is lower since the solution is not required to be optimal. This enables the constrained time-dependent adaptive eco-routing.