Papers by Keyword: Global Positioning System (GPS)

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Authors: Yi Te Chiang, He Sheng Wang, Yung Nien Wang
Abstract: In this paper, we propose a novel method to generate pseudo-random-noise (PRN) bits for navigation applications. In the present method, the code sequence generator is constructed based on two chaotic logistic maps running parallel and starting from independent initial conditions. The logistic map is a simple mathematical model that shows bewildering complex behavior. By appro-priately setting the initial conditions, the PRN sequence is then generated by comparing the outputs of both logistic maps. Several simulations are set up to verify the correlation properties of the pseudo-random bit generator (PRBG). The result shows that the code sequences generated by the proposed PRBG have great auto- and cross-correlation properties, which are very similar to the PRN sequences used by GPS navigation system. The RPBG sequences are therefore suitable for signal ranging that is used comprehensively in the navigation system. On the other hand, the chaotic nature of the proposed PRBG codes can provide more secure communication than the traditional PRN sequences. The proposed PRN sequences are well suitable to be incorporated with the so-called chaotic shift keying (CSK) modulation.
Authors: Muhammad Ushaq, Fang Jian Cheng, Ali Jamshaid
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.
Authors: Ji Hua Hu, Wei Tang, Hai Ying Xie
Abstract: Vehicle monitor becomes popular in china, but it is difficult to monitor vehicle runs in continuous Tri-dimensional Traffic Area. This paper supposes a vehicle monitor framework, which integrates X3D, XML with GPS, and it realizes vehicle movement model, to locate exactly which road a car run in, and to watch cars runs in TTA. The framework is proved to be feasible by test done in Guangzhou city of china, which can also be applied in traffic simulation and vehicle behavior analysis.
Authors: Yong Xiang, Yan Bin Luo, Ren Jie Zhou, Cheng Yan Ma
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.
Authors: Xiu Long Xu, Zhen Ying Xu, Ran Ran Xu, Jia Kun Jiang, Xiao Dong Guo
Abstract: In this paper, a real-time location and reset method of cylindrical FPSO is presented based on GPS. In this method, the coordinate system of PFSO is determined by three GPS locators installed on the platform. Then, through coordinate transformation according to the marine engineering coordinate system established before, we can get the displacement and the orientation of FPSO, so as to achieve its real-time location. Finally, this displacement and orientation information is assigned to relative thrusters, which are evenly distributed with an angle 22.5°on both sides of the “+” and “-” X and Y axis, according to the calculating results of the optimization model.
Authors: Keun Hong Chae, Hua Ping Liu, Seok Ho Yoon
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.
Authors: Xin Zhao, Jun Gang Miao, Jing Shan Jiang
Abstract: This paper propose a new design of dual-band GPS microstrip antenna by spreading out the patches on the ground plane. With two independent patches, the antenna operates at two frequencies, which are available in different GPS systems. When patches are spread on the ground plane, the beam of radiation pattern shifts away and axial ratio degrades. In this design, two patches are printed on two independent substrates with a compact design, and positions of two antennas are optimized. Finally, above problems are solved with a conductive vaulted base. The design procedure is discussed, and optimized results are presented.
Authors: Chun Yi Liu, Kuo Tai Tang, Shrane Koung Chou
Abstract: As bus passengers often spend substantial amounts of time waiting for buses, many hope for access to real-time transit information to fulfill passenger demands for routes, station location, transit duration, and bus frequency information. This study develops a “Smart Bus Dynamic Transit System” using cellular phones to combine internet, XML documents, GPS positioning and transit path planning models to allow the inquiry of real-time bus and station locations. Users will be able to rapidly obtain knowledge of optimal transit locations and times, as well as estimated arrival times as reflected on Google Map; thus reducing passenger transit time and improving public transportation system efficiency.
Authors: Jian Wang
Abstract: A new adaptive method for phase measurement and its implementation system are proposed in this paper. It can be applied in GPS system to help locate the position with high accuracy. The algorithm is based on multiple sampling of sine signals. It can adapt the sampling frequency to the changes in the frequency of measured signals, and calculates the optimal value of sampling frequency. After processing the sampled data through multiple sampling, we can obtain the high-precision phase value.
Authors: Er Shen Wang, Tao Pang, Zhi Xian Zhang
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).
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