共查询到18条相似文献,搜索用时 164 毫秒
1.
实际的全球定位系统(GPS)测量中,因为多径效应的影响而使定位精度降低。而环路滤波方法中的Strobe相关器可以有效抑制长多径,但对短多径常常无效。为克服此缺点,本文在传统Strobe相关器的基础上,细化对于同相多径的情况下建模,对于传统Strobe相关器的表达式进行修正,得到改进型Strobe相关器。接着结合SPIRENT4500GPS信号模拟器和东南大学ASIC中心自主研发的多通道GPS接收机SEU-GPS,进行模拟信号测试,验证了算法的有效性。 相似文献
2.
基于全球定位系统(GPS)辐射源的无源雷达,利用目标对GPS的反射信号工作,由于利用的是非合作信号,因此干扰抑制是此类雷达信号处理的重要研究内容.在本文的研究中,提出采用功率倒谱分析法对多径干扰进行分离.仿真结果结果表明,所采用的方法能很好的抑制多径干扰,为此类雷达的信号处理系统的设计提供了仿真依据. 相似文献
3.
4.
5.
6.
7.
8.
空时联合处理由于优异的性能在GPS抗干扰方面广泛的应用,但是由于抗干扰性能取决于空时维数限制了其在干扰是非平稳或天线平台快速移动的情况时的应用。基于此,提出了一种多径环境下GPS信号的干扰抑制方法,在同样的抗干扰性能的情况下具有较小的复杂度和较好的抑制多径信号的能力,并通过仿真验证了结果。 相似文献
9.
多径干扰信号是导航接收机测量过程中遇到的主要误差源之一。针对Galileo系统以及GPS现代化过程中拟使用的BOC调制信号,研究了基于Strobe相关的BOC信号跟踪过程中的多径抑制方法。分析了多径效应对码跟踪精度的影响,从鉴相函数入手,提出了一种新的En-Strobe相关法。运用窄相关法、Strobe相关法和En-Strobe相关法对BOC(1,1)信号和CBOC(6,1,1/11)信号进行多径抑制性能分析。仿真结果表明En-Strobe相关法在中短延迟的情况下能够很好的抑制多径误差,且性能优于窄相关法和Strobe相关法。 相似文献
10.
多径问题是影响GPS信号接收的主要干扰问题.通过研究GPS接收机的基本原理和实现方式,利用Xilinx公司的xc3s1000型号FPGA,设计一个仿真实验平台.针对多径处理的需要,使用Verilog HDL语言设计了运用反馈移位寄存器产生的C/A码序列及起始位置脉冲,移相、衰减、混合、AGC(自动增益控制)模块和码环积分相关器,解决了几个关键技术与问题,实现了数据的传送与存储. 相似文献
11.
This paper investigates the constructive use of multipath reflections of Global Positioning System (GPS) signals for navigation in urban environments. Urban navigation applications are generally characterized by a significant presence of multipath signals. In order to maintain reliable and accurate navigation capabilities, it is critical to distinguish between direct signal and multipath. At the same time, multipath reflections can be exploited as additional measurements for those cases where the number of direct path satellites is insufficient to compute the navigation solution. The paper develops a method for the identification of multipath reflections in received satellite signals: i.e., multipath is separated from direct signal and a line-of-site between the GPS receiver and a multipath reflecting object is determined. Once multipath reflections are identified, they can be used constructively for navigation. The method presented in the paper exploits an open-loop batch-processing GPS receiver, laser scanner and inertial navigation system (INS) to identify multipath reflections in received satellite signals. Experimental GPS, inertial and laser scanner data collected in real urban environments are applied to demonstrate identification of multipath reflections. 相似文献
12.
Fei Xiang Guisheng Liao Cao ZengWeiwei Wang 《AEUE-International Journal of Electronics and Communications》2013,67(10):839-847
A novel technique for mitigating the multipath-induced code delay estimation error in Global Positioning System (GPS) is proposed. In contrast to conventional methods that aim to eliminate multipath signals, the proposed method exploits them to enhance the direct signal without affecting the accuracy of GPS code delay estimates. To achieve this, coherent accumulation of the received GPS signals is first done by transforming the received data into frequency domain and the parameters of multipath signals are then estimated by sparse reconstruction algorithm. Subsequently, a modified local reference signal is employed in delay lock loop (DLL) of the GPS receiver, which mitigates the pseudo-range estimation error and increases the correlation value of direct GPS signal. Simulation results demonstrate the performance and robustness of the proposed method. 相似文献
13.
14.
Sul Gee Park Deuk Jae Cho 《International Journal of Satellite Communications and Networking》2017,35(2):123-137
Intelligent Transport System applications require accurate and reliable positioning. When stand‐alone global positioning system (GPS) is used in urban areas, the results dramatically degrade, because of signal outages and multipath. This paper unveils new signal processing techniques for carrier phase‐based navigation in urban environments. The techniques identify multipath or weak signals using carrier phase based receiver autonomous integrity monitoring, and abnormal signals and situational measurements are eliminated or estimated. To estimate the carrier phase during a short time period when GPS signals is blocked, this paper uses carrier phase statistics. The performance of the proposed method is verified, through a car test. The test environment has many signal outages and multipath because of high buildings. Many abnormal signal conditions occurred during the test, and the results confirmed that the proposed method performed better than the basic stand‐alone GPS approach when compared with GPS/inertial navigation system (INS) integrated navigation results. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
15.
Gary Brodin Peter Daly 《International Journal of Satellite Communications and Networking》1997,15(1):25-34
It is well known that multipath represents a major error source in differential GNSS positioning. Errors produced are unique to each antenna position and so are uncorrelated between the reference station and the mobile receiver. Reduction techniques, such as narrow correlator spacing1 and the multipath estimating delay lock loop (MEDLL)2 have improved the situation. However, reflected signals emanating close to the antenna are not reduced by either technique. Carrier multipath is a particular problem because short delay multipath signals cause maximum carrier errors. This study describes the analysis that has been carried out into code and carrier tracking in the presence of multipath. Code tracking in this situation produces a non-zero mean error,3 and the source of this bias has been investigated. Code and carrier multipath errors of the global orbiting navigation satellite system (GLONASS) have been compared with those of the global positioning system (GPS). The effects of pre-correlation filtering on code and carrier multipath errors have been determined using data from a measured correlation function. The multipath fading bandwidth is also discussed, and fast and slow fading effects are presented. A comparison has been made of the performance of typical coherent and non-coherent code discriminators in the presence of multipath. The performance of the GPS and GLONASS P code signals have been determined with respect to code and carrier multipath errors. © 1997 by John Wiley & Sons, Ltd. 相似文献
16.
Comparison of EML and DOT discriminator DLL multipath performancein GPS/GLONASS navigation receivers
The impact of multipath signals on the code phase tracking in digital GPS/GLONASS navigation receivers is analysed. As an interesting result it is for example, shown that for moderate correlator spacings a DOT discriminator DLL offers a larger potential of multipath error reduction by code phase smoothing than an EML discriminator DLL due to significantly smaller mean code phase tracking errors 相似文献
17.
A new direction-of-arrival (DOA) estimation method for coherent global positioning system (GPS) signals is proposed. It is applicable to the GPS propagation environment with rich multipath, strong interferences and noise. According to the properties of oblique projection, interferences and noise are first suppressed and only the coherent GPS signals are retained by projecting the received signal onto the signal subspace. Then, the coherent GPS signals are resolved by the Toeplitz decorrelation scheme. Using the proposed method, interferences and noise can be suppressed simultaneously, and more accurate DOA estimation for coherent GPS signals can be obtained in GPS propagation environment. Simulation results demonstrate the effectiveness of the proposed method. 相似文献
18.
GPS positioning accuracy in indoor and urban canyons environments is greatly affected by multipaths due to distortions in
its autocorrelation function. In this paper, the first sidelobe of Pseudorandom Noise (PN) code autocorrelation is studied
and a new multipath mitigation technique based on PN code autocorrelation function is presented. This new technique relies
on the detection of the partial autocorrelation function that is affected by multipath signals. The increase in fractional
delay of the line-of-sight (LOS) signal is calculated. Simulation results indicate that the proposed technique has superior
performance compared with the 0.1-chip-spacing narrow correlator on mitigating multipath signals, especially the short-delay
multipath signals.
Zhang Zhen obtained his Bachelor’s Degree from Beijing Information and Technology Institute in 1999, Master’s Degree from Tsinghua University,
Beijing China, in 2002. He now is a Ph.D. student in Nanyang Technological University. Currently he also works as a Research
Associate in the Positioning and Wireless Technology Center (PWTC), NTU. His research interest includes multipath mitigation
for GPS, software GPS receiver design, indoor GPS as well as Ultra Wide Band (UWB) based ranging systems.
C. L. Law is an Associate Professor in School of EEE, NTU and the Director of PWTC. Dr. Law’s current research area is in Wireless
Networks. His research topics are in microwave integrated circuits, indoor wireless channel modeling, analysis of indoor wireless
LAN performances and in techniques for overcoming the time-dispersion distortions in high speed wireless LAN.
E. Gunawan is an Associate Professor in School of EEE, NTU and his research interest includes Error Correction Codings, Modeling of
Cellular Communications Systems, Power Control for CDMA Cellular Systems, MAC Protocols, Multicarrier Modulations, Multiuser
Detections, Space-time Coding, Radio-location Systems, UWB and its applications for Human Body Vital Signs Detection, and
Powerline Communications. 相似文献