| With the development of wireless communications, such as WiFi WiMax ZigBee Adhoc and Blutooth, which are widely used in office home workshop and park, it is the time for the wireless internet in 21st century. Wireless networks based on positioning technology have more prospects, wireless localization technology has been everywhere in people's daily lives.UWB (Ultra-WideBand) system is defined as the system of which the bandwidth and the system center frequency ratio is greater than 20%, or an absolute bandwidth is greater than 500MHz. It was emerged in the 1960's. the early research was mainly concentrated in the pulse generation and detection technology. Through Harmuth, Ross and Robbins et al study, UWB technology was an important development in the 1970's, most of them concentrated in the application of radar systems, including ground-penetrating radar system. From the late 1980's, it has been called the "carrier" radio, or impulse radio. In 1989, the United States Department of Defense named it "ultra-bandwidth" at the first. the main features of UWB technology are as follows:(1) Architecture of the UWB system is simpler and easy to integration.(2) high-speed data transmission. The bandwith of UWB is very wide, which in exchange for high-speed data transmission. The speeds is up to 500Mbit/s in 10m, which make the implementation of personal communications and wireless LAN an ideal modulation.(3) Low-Power. UWB transmitter power is only equivalent to one-thousandth of the mobile cellular. It can greatly extend the battery life.(4) Hidden, anti-jamming, and safety. UWB systems transmit power spectral density is very low. Compare with other wireless communications system is equivalent to the level of noise. The pulse signal detection is very difficult. The probability of being intercepted is low, and security is high(5) Ability to distinguish the multi-path. Ultra-bandwidth radio transmission the single-pulse is very short duration and low duty cycle, it is easy to isolate multi-path components in order to take full advantage of the energy emission signal.(6) Positioning accuracy. Ultra-bandwidth wireless bandwidth is very wide, has a strong penetrating ability of leaves and obstacles and can be carried out under the ground in the interior and precise positioning with centimeter-level positioning accuracy.UWB system with good penetration, low power consumption, anti multipath effect, safety, low system complexity, can provide advantages such as precise positioning accuracy. As a result, UWB localization technology has become a focus of current research . Based on time delay estimation localization is the most suitable method for UWB systems by a large number of research proved. The accuracy of UWB localiztion system depends on the accuracy of the time delay of UWB signal.In the thesis, based on the summary and analysis of the traditional methods of wireless localization, the study on the UWB signal time-delay estimation problem and the localization technology is done. the whole of the thesis is divided into eight chapters as follows:In chapter one, the main research of this thesis is introduced, include the background and significance. UWB positioning advantages and application are described. The state of UWB positioning technology research is intoduced.In chapter two, introduction and analysis of UWB systems is presented, include pulse waveforms, modulation and channel model. The simulations of PPM-TH,BPSK-TH,BPSK-DS waveforms and Channel models of IEEE802.15.3 and IEEE802.15.4 are made. Follow-up studies are based on the content. The analysis and basic principles of UWB positioning technology is shown in Chapter three. It is the overview of the UWB localization.In chapter four, some time delay estimation methods are proposed. High resolution time delay estimation based on MUSIC algorithm is extended to UWB delay estimation.Higher order cumulants and based on the propagator method time delay estimation algorithm are discussed deeply. Simulation show that, the higher-order cumulants algorithm can solve the low resolution and the Gaussian noise-sensitive in the traditional correlation algorithm, but in the dense multipath environment can not be effective estimate the number of multi-path and time delay. Howerver based on the propagator the time-delay estimation method can solve the problem.In chapter five, the TOA estimation of UWB signal based on MP is proposed, and some simulations are shown. The method without covariance matrix computing and peak seraching in MUSIC algorithm can reduce the complexity of system.In chapter six, the joint TOA and DOA estimation of UWB signal based on MP is proposed, and some simulations are shown that the method is available.. In chapter seven, a positionging method for the lunar rover is proposed which is based on beacon network. UWB location and tracking algorithm is discussed in this chapter.The summary and outlook is presented in chapter eight.Innovate point in the thesis are as follows:1. The traditional methods of wireless location is meticulous researched. Higher order cumulants and the MUSIC algorithm are applied to the UWB positioning system. Research shows that in the Gaussian noise environment, the performance of the third-order cumulants and fourth-order cumulant method is better than the correlation method. However, they can not work in the multi-path-intensive environments. This conclusion is a useful complement to the UWB wireless location technology and traditional wireless location technology.2. TOA algorithm based on the propagator is proposed and improved. The method is based on the propagator and frequency domain smoothing techniques, so it is effectively improving the positioning accuracy of UWB.3. TOA estimation algorithm based on matrix pencil (MP) is proposed. With the advantages of temporal resolution, a simple method to positioning moving targets is proposed. The method is based on the MP method and triangular position algorithm. With accurate TOA estimates and the relationship between two fixed receiver and the location of a moving target, the locating and tracking is available. The proposed method is quick and low load in calculation, in addition of the simplified localization. The simulation results show that the RMSE (Root Mean Square Error) of the MP method is similar to that of MUSIC method at low SNR, while it is better at high SNR. In LOS (Line of Sight) and multipath environments, the positioning method provides high precision, and avoids the error produced in the conversion between time and angle.4. UWB positioning system based on joint TOA and DOA estimation is proposed, which is based on matrix pencil (MP), then the relative coordinates of the target can be known according to TOA and DOA parameter. The approach with one reciever has the advantage of low cost of system. Through simulations, it is proved that the accuracy of delay and angle estimation is high, which can achieve centimeter-level,. It is a simple and practical method of UWB positioning systems proposed in this paper.5. The application of the lunar rover vehicle with UWB is described. Combined with parameter estimation methods mentioned in this thesis, a beacon-based network positioning method for lunar rover is proposed. A new framework of positioning and tracking system for the lunar rover is establishment. The rover delivery the beacon when moving to a fit position, then the position of lunar rover can be estimated through the beacon network with the proposed TOA method in chapter five.
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