Papers by Keyword: Global Positioning System (GPS)

Abstract: The paper presents an extensive theoretical background related to the travel time and the studies that were conducted during the recent years on the subject. As a concept, travel time is related to the period of time spent in travelling between two different points in space. The analysis focuses on several aspects related to the travel time concept such as its usefulness, its influencing factors, and data collection methods for its determination. In order to also provide a practical outcome, the main interurban road connection between Cluj-Napoca and Tîrgu-Mureş was studied. The road trespasses both urban and rural localities in the North-Western of Romania. For the data collection process, a GPS-based equipment was placed on a test vehicle to run the route for multiple times, at different days and hours. The collected data were studied by means of statistical analysis in order to establish the most relevant aspects of the travel time. The research goal of the paper was to evaluate the influence exerted by demographics and type of locality on travel time by means of eventual delays. The main findings were employed to analyze the traffic conditions as well as the parameters that have a major impact on them. According to the results of the analysis, the traffic flow on the interurban route is best described by the travel time and consequently the delays registered due to multiple obstructive elements such as railway level crossings, pedestrian crossings within the localities, and level intersections between different roads category. However, according to the study, it can also be concluded that travel time and therefore the eventual delays are not influenced to a great extent by neither the type of transited localities - urban or rural, nor the demographics.

Abstract: Private and public transportations are use as common mobility of people, making it important to know where traffic congestions, car accidents and other related vehicular activities that may ruin your way to office works or to your destinations be avoided. Philippines is known to be one of the most traffic congested in the world due to uncontrollable volumes of cars running in major streets every day. In this paper, a proposed wireless device that can be attached to a vehicle was developed to track the route using global positioning system, perform geo fencing and perform controlling mechanism to help the driver locates a shortest path, avoid traffic jams, and do messaging and traffic advisories based on contacts and information stored in the software utilities. Based on initial testing, the software is capable of recording and reading vehicle logs, activating GPS route, reading accelerometer log, and reading compass log as bases of controlling mechanism while the device is activated, WiDrive. Result shows that WiDrive is reliable as it successfully mapped to the GPS, and passed the crash accelerometer test at different distance. If given a chance to improve and implement in a wide scale testing, an exponential benefits can be achieved.

Abstract: In this paper, we propose a side-peak cancellation scheme for unambiguous BOC signal tracking. We obtain partial correlations using a pulse model of a BOC signal, and then, we finally obtain an unambiguous correlation function based on the partial correlations. The proposed correlation function is confirmed from numerical results to provide an improved tracking performance over the conventional correlation functions.

Abstract: Aiming at the weight degeneracy phenomena in particle filter algorithm, a resampling method improving the diversity based on GA-aided particle filter was presented. Taking the advantage of genetic algorithm ( GA ) in selection ,crossover and inheritance to make up for the shortcoming of resampling. Genetic operation on particles in real number domain is adapted to reduce the complex of the genetic algorithm. And the evolutionary idea of genetic algorithm was combined with particle filter, by using selection, and mutation to improve the weight degeneracy and diversity of particle filter. This GA-aided particle filter was applied in the established GPS system nonlinear dynamic state space model. The experimental results based on the collected real GPS data is compared with the tradition particle filter, and compared with the effective number of particles and particle distribution. The experimental results indicated that the GA-aided particle filter can increase the number of particle, and effectively solve the particle degradation phenomena, the estimation accuracy of GA-aided particle filter is better than that of particle filter (PF).

Abstract: Using GPS observations, this article studied the global TEC’s effect and its variation characters during the magnetic storm on August 5^th, 2011. Results show that after sudden commencement and deep main phase of the magnetic storm, there are strong positive ionospheric TEC disturbances in the area along middle and low latitude with local time of 12:00 at noon. Besides, compared with TEC reference value, the maximum increase values are respectively 21.26 TECU and 25.29 TECU. TEC’s abnormal decline appeared in some area of high latitude at mid night on the northern semi-sphere. The analysis results reflect that the ionospheric disturbances are dependent on the local time. Moreover, observations on the BRMU GPS station show that the rate of TEC (ROT) rose and fell quickly, and its standard deviation ROTI index increased from less than 0.5 TECU/min to lager than 1.5 TECU/min, which meant that TEC temporal and spatial gradient had become larger and larger during the storm. The global ROTI map reflects the strong irregularity of the ionosphere density structure in the high-latitude area with higher time resolution in case of storm sudden commencement, and the maximum value rose up to 6 TECU/min. Then, the ionospheric irregularity appeared in wide area of the globe after noon.

Abstract: In Indian Transport System identification of faulty vehicle is a challenging task for the enforcing authority within a specified time. Faulty vehicles include hit and run accident vehicle, traffic violators, theft vehicles, escaping an accused in a vehicle and non-payment of tax vehicle etc. In the existing Intelligent Transport System (ITS), only the vehicles are being monitored, instead of catching the faulty vehicle. In this methodology, the vehicles are controlled by controlling the fuel mixture through Global Positioning System (GPS) and Electronic Control Unit (ECU) within stipulated time duration from the control room itself. To conclude, the prime objective of this work involves conducting an experiment to monitor as well as controlling the vehicle through GPS from the control room itself.

Abstract: GPS positioning system is installed in taxis and most mobile phones support GPS positioning function at present. GPS phones are used in the taxi to achieving intelligent scheduling based on this basis. The taxi intelligent dispatch system based on GPS is proposed, improve the traditional Dijkstra scheduling algorithms by setting taxi maximum reasonable scheduling range, experimental results show that improved algorithms reduce the time complexity and improve scheduling efficiency. Meanwhile the traffic jam information can be sent to the dispatch center and make scheduling algorithm more reasonable by combined with above information.

Abstract: A 1.575GHz SiGe HBT(heterojunction bipolar transistor) low-noise-amplifier(LNA) optimized for Global Positioning System(GPS) L1-band applications was presented. The designed LNA employed a common-emitter topology with inductive emitter degeneration to simultaneously achieve low noise figure and input impedance matching. A resistor-bias-feed circuit with a feedback resistor was designed for the LNA input transistor to improve the gain compression and linearity performance. The LNA was fabricated in a commercial 0.18µm SiGe BiCMOS process. The LNA achieves a noise figure of 1.1dB, a power gain of 19dB, a input 1dB compression point(P1dB) of -13dBm and a output third-order intercept point(OIP3) of +17dBm at a current consumption of 3.6mA from a 2.8V supply.

Abstract: Strapdown Inertial Navigation Systems (SINS) displays position errors which grow with time in an unbounded manner. This degradation is due to the errors in the initialization of the inertial measurement unit, and inertial sensor imperfections such as accelerometer biases and gyroscope drifts. Improvement to this unbounded growth in errors can be made by updating the inertial navigation system solutions periodically with external position fixes, velocity fixes, attitude fixes or any combination of these fixes. The increased accuracy is obtained through external measurements updating inertial navigation system using Kalman filter algorithm. It is the basic requirement that the inertial data and data from the external aids be combined in an optimal and efficient manner. In this paper an efficient method for integration of Strapdown Inertial Navigation System (SINS), Global Positioning System (GPS) is presented using a centralized linear Kalman filter.

Abstract: The complementary characteristics of the Strapdown Inertial Navigation System (SINS) and external non-inertial navigation aids like Global Positioning System (GPS) and Celestial Navigation System (CNS) make the integrated navigation system an appealing and cost effective solution for various applications. SINS exhibits position errors owing to errors in initialization of the inertial measurement unit (IMU) and the inherent accelerometer biases and gyroscope drifts. SINS also suffer from diverging azimuth errors and an exponentially increasing vertical channel error. Pitch and roll errors also exhibit unbounded growth with time. To mitigate this behavior of SINS, periodic corrections are opted for through measurements from external non-inertial navigation aids. These corrections can be in the form of position fixing, velocity fixing and attitude fixing from external aids like GPS, GLONASS (Russian Satellite Navigation System), BEIDU(Chinese Satellite Navigation System) and Celestial Navigation Systems (CNS) etc. In this research work GPS and CNS are used as external aids for SINS and the navigation solutions of all three systems (SINS, GPS and CNS) are fused using Federated Kalman Filter (FKF). The FKF differs from the conventional Central Kalman Filter (CKF) because each measurement is processed in Local Filters (LFs), and the results are combined in a Master Filter (MF). FKF is a partitioned estimation method that uses a two stage data processing scheme, in which the outputs of sensor related LFs are subsequently combined by a large MF. Each LF is dedicated to a separate sensor subsystem, and uses data from the common reference such as SINS. The SINS acts as a cardinal system in the combination, and its data is also available as measurement input for the master filter. In this research work, information from the GPS and the CNS are dedicated to the corresponding LFs. Each LF provides its solutions to the master filter all information is fused together forming a global solution. Simulation for the proposed architecture has validated the effectiveness of the scheme, by showing the substantial precision improvement in the solutions of position, velocity and attitude as compared to the pure SINS or any other standalone system.