共查询到20条相似文献,搜索用时 31 毫秒
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随着全球定位系统(GPS)的日益普及,其信号的稳定性和准确性成了人们关注的焦点。然而,GPS信号常常受到外界的干扰和影响,还存在一些不足。抗干扰技术在GPS中的应用越来越重要,其不仅能提高GPS信号的质量,还能提高其精度和可靠性。尽管GPS信号在不同环境下的表现有所差异,但只要采用了有效的抗干扰技术,就能最大程度地避免GPS信号被干扰和影响。文中详细分析和总结了GPS抗干扰技术的研究现状和进展,并提出了一些可行的解决方案和建议。 相似文献
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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
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GPS接收机信号捕获方法的改进与实现 总被引:1,自引:0,他引:1
在GPS卫星定位中,由于卫星和接收机之间的相对运动产生高达10kHz的多普勒频移,同时大多数情况下卫星信号容易被遮挡,接收到的信号都比较弱,需要有一种有效的捕获方法实现GPS信号的捕获。分析了已有捕获方法的特点和缺陷,提出了一种改进的基于循环相关的捕获方法,并进行验证,表明该方法能实现相对弱信号的快速捕获。 相似文献
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Suk‐seung Hwang John J. Shynk 《International Journal of Satellite Communications and Networking》2011,29(4):315-332
The Global Positioning System (GPS) utilizes low‐power spread‐spectrum signals and thus is vulnerable to various types of high‐power interference sources. It requires at least four satellites for estimating three‐dimensional user positions and the receiver clock bias. In this paper, we propose a blind adaptive GPS receiver that is based on a new despreader and the one‐stage constant modulus (CM) array. The despreader consists of a conventional GPS despreader and a so‐called null despreader, which together modify the received signal so that the CM array can extract the GPS signal of interest. The beamformer not only rejects jammers and extracts the GPS signal of interest without explicit direction‐of‐arrival (DOA) information of any of the signals but also it has a low computational complexity compared with conventional techniques, such as minimum‐variance distortionless‐response (MVDR) beamforming. As a conventional despreader can recover only one GPS signal, multiple despreaders are usually required for separating multiple GPS signals. We also explore an extension of the proposed null despreader to detect multiple GPS signals. Computer simulation examples are presented to illustrate the performance of the receiver for different types of jammer signals. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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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
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一种低SNR环境下的跟踪环路 总被引:1,自引:0,他引:1
低信噪比(SNR)环境下GPS信号的跟踪一直是近年来研究的热点,主要介绍了在GPS信号较弱的条件下,通过增加积分时间来提高载波环跟踪精度的方法。详细介绍了GPS载波环工作原理,并推导了载波环滤波器增加积分时间的理论依据。最后,采用GPS模拟信号源产生的数据进行环路性能仿真,实验结果表明该环路设计可在-30dB的SNR环境下正常工作。 相似文献
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GPS信号的多普勒频移和时移分析推算 总被引:1,自引:0,他引:1
对GPS信号总是采用相干接收和处理,本地信号需要时刻保持与卫星信号之间频率和码相位的严格对准。GPS卫星和用户的运动将使接收信号的频率发生改变,同时也将使信号中的码速率发生改变,从而影响对信号的捕获、跟踪和对伪距的测量,这成为GPS接收机设计者和对抗者关注的焦点之一。文章仔细分析推算了多普勒频移和时移及其变化率,取得了重要数据,并简要分析了对环路的影响。 相似文献
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GPS测量,尤其是差分GPS测量,多径信号是主要的误差来源,会引起定位精确度的恶化。因此基于GPS多径影响分析,提出采用空时处理抗多径的方法,但是由于大的计算量,必须做降秩处理,并给出了仿真的结果。 相似文献
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GPS(Global positioning system,全球定位系统)目前已经得到了广泛的应用,尤其是高敏度GPS接收技术已成为当今的研究热点。本文主要介绍了GPS的信号特点及目前高敏度GPS的需求,设计了高敏度GPS接收机系统.对高敏度GPS接收机的捕获跟踪进行了仿真分析和研究。 相似文献
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John Scott Parker Pascal Mickelson Jeremy Yeak Kevin Kremeyer Jason Rife 《Journal of Infrared, Millimeter and Terahertz Waves》2016,37(10):1021-1042
This paper demonstrates the feasibility of GPS-like ranging at terahertz (THz) frequencies. It is well established that GPS carrier signals are vulnerable to jamming via radio-frequency interference (RFI). As a result, there is a need for alternative radionavigation systems. THz signals offer a compelling option. Because of their high frequency (roughly ×100 higher than GPS), THz signals can be used to make highly precise range measurements. In addition, the large separation between the GPS and THz frequencies means that interference at GPS frequencies is very unlikely to impact the THz band. This paper lays the groundwork for a GPS-like ranging capability at THz frequencies. To this end, we identify key differences between THz hardware and GPS (radio frequency) hardware; we experimentally evaluate performance of a 0.30-THz system on a compact outdoor test range, and we introduce a measurement error model that highlights the distinctive role that multipath interference plays at THz frequencies. 相似文献
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Detection and Processing of bistatically reflected GPS signals from low Earth orbit for the purpose of ocean remote sensing 总被引:8,自引:0,他引:8
Gleason S. Hodgart S. Yiping Sun Gommenginger C. Mackin S. Adjrad M. Unwin M. 《Geoscience and Remote Sensing, IEEE Transactions on》2005,43(6):1229-1241
We will show that ocean-reflected signals from the global positioning system (GPS) navigation satellite constellation can be detected from a low-earth orbiting satellite and that these signals show rough correlation with independent measurements of the sea winds. We will present waveforms of ocean-reflected GPS signals that have been detected using the experiment onboard the United Kingdom's Disaster Monitoring Constellation satellite and describe the processing methods used to obtain their delay and Doppler power distributions. The GPS bistatic radar experiment has made several raw data collections, and reflected GPS signals have been found on all attempts. The down linked data from an experiment has undergone extensive processing, and ocean-scattered signals have been mapped across a wide range of delay and Doppler space revealing characteristics which are known to be related to geophysical parameters such as surface roughness and wind speed. Here we will discuss the effects of integration time, reflection incidence angle and examine several delay-Doppler signal maps. The signals detected have been found to be in general agreement with an existing model (based on geometric optics) and with limited independent measurements of sea winds; a brief comparison is presented here. These results demonstrate that the concept of using bistatically reflected global navigation satellite systems signals from low earth orbit is a viable means of ocean remote sensing. 相似文献