Improving the performance of anti-GPS signal (original) (raw)
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Applied Sciences, 2020
The received global navigation satellite system (GNSS) signal has a very low power due to traveling a very long distance and to the nature of the signal's propagation medium. Thus, GNSS signals are easily susceptible to signal interference. Signal interference can cause severe degradation or interruption in GNSS position, navigation, and timing (PNT) services which could be very critical, especially in safety-critical applications. The objective of this paper is to evaluate the impact of the presence of jamming signals on a high-end GNSS receiver and investigate the benefits of using a multi-constellation system under such circumstances. Several jamming signals are considered in this research, including narrowband and wideband signals that are located on GPS L1 or GLONASS L1 frequency bands. Quasi-real dynamic trajectories are generated using the Spirent™ GSS6700 GNSS signal simulator combined with an interference signal generator through a Spirent™ GSS8366 unit. The performance evaluation was carried out using several evaluation metrics, including signal power degradation, navigation solution availability, dilution of precision (DOP), and positioning accuracy. The multi-constellation system presented better performance over the global positioning system (GPS)-only constellation in most cases. Moreover, jamming the GPS band caused more critical effects than jamming the GLONASS band.
Methods of Improving the Jamming Resistance of GNSS Receiver
Annual of Navigation
Jamming of GNSS signals can be both a consequence of accidental activities and an intentional act. This issue is lately discussed as an essential threat for the use of satellite navigation systems. This is especially dangerous in the face of common usage of GPS - like systems in everyday life and the great belief of everyday users in the truth of devices indications. In spite of the legal prohibition of using them, jammers are commonly accessible, especially in the Internet. Until recently even specialists have shared the conviction that the broadband GPS signal is not a subject of disturbances in contrast to older wireless communication techniques because its power level is below natural level of noises and in addition it is randomly coded. But nowadays jammers are very often successfully applied, which is confirmed in many reports. The average user has not the suitable knowledge about the specificity of the jamming and has no technical possibilities of the detection of jammer sign...
GPS ANTI-JAMMING TECHNIQUE USING SMART ANTENNA SYSTEMS
This paper presents a global positioning system (GPS) anti-jamming technique using a smart antenna system. In anti-jamming systems, adaptive array antennas are used to estimate the direction of signals arriving at the antenna and spatially filter the desired signal from the unwanted signals by adaptively controlling the direction of the maximum radiated beam. In this study, the uniform linear array was used for the smart antenna configuration. The work compared the performance of non-blind adaptive algorithms with blind algorithms for adaptive beamforming. Non-blind adaptive algorithm using least mean square (LMS) algorithm and blind algorithm using constant modulus algorithm (CMA) was studied and implemented for adaptive beamforming while estimation of signal parameters via rotational invariance technique (ESPRIT) and multiple signal classification (MUSIC) algorithms were implemented for the direction of arrival (DOA) estimation. The effect of varying the number of elements in the antenna array and the required spacing between them was also investigated. Results of comparison carried out using numerical analysis showed that both algorithms performed well for the DOA estimation, with MUSIC algorithm producing a better direction of arrival spectrum with little or no minor peaks. For the beamforming, both LMS and CMA produced maximum radiation in the direction of the desired signal. LMS placed deeper nulls in the directions of interference with faster convergence and fewer errors as compared with CMA that presented errors and was able to suppress the interference to a minimal extent. It was also shown that as the number of elements in the array increases, a more directive beam and DOA spectrum is produced.
Information and Telecommunication Sciences, 2022
Background. Currently, in radio navigation systems of the various purposes, the urgent issue is stability increase of the GPS signal reception under such a jamming and spoofing types of the interference influence. In this article, the authors propose a new solution to the stability increase problem of the GPS signal reception against the jamming and spoofing interference based on the spatial selectivity of the receiver antenna. Spatial selectivity is provided through the integrated application of phased array digital beamforming technology and the use of the TLE NORAD information. Objective. The research goal is to develop a methodology for the integrated identification of interference sources to the radio navigation system and to increase the noise immunity for receiving radio navigation signals via spatial selection through the digital beamforming technologies utilization. Methods. For the research process, theoretical methods for the digital beamforming of receiving phased antenna system were used as well as the description of a two-line NORAD information element content, and calculation algorithms for the spacecraft current position. Results. As a result of the research, the GPS signal reception model was formed using spatial selection of GPS signal sources and interference sources, the technique to increase the stability of GPS signal reception under the jamming and spoofing types of interference influence was developed, the block diagram was suggested for the receiving device that implements the developed technique through the integrated application of the digital beamforming technology of the phased array antenna and the TLE NORAD information utilization. Conclusion. A conceptual idea of the method and a technical solution for the proposed method implementation were submitted. The method implementation will improve the stability of GPS signal reception under the influence of jamming and spoofing types of interference.
GPS Swept Anti-Jamming Technique Based on Fast Orthogonal Search (FOS)
Sensors (Basel, Switzerland), 2021
Recently, there has been growing demand for GPS-based reliable positioning, with the broadening of a range of new applications that mainly rely on GPS. GPS receivers have, recently, been attractive targets for jamming. GPS signals are received below the noise floor. Thus, they are vulnerable to interference and jamming. A jamming signal can potentially decrease the SNR, which results in disruption of GPS-based services. This paper aims to propose a reliable and accurate, swept anti-jamming technique based on high-resolution spectral analysis, utilizing the FOS method to provide an accurate spectral estimation of the GPS swept jamming signal. resulting in suppressing the jamming signal efficiently at the signal processing stages in the GPS receiver. Experiments in this research are conducted using the SpirentTM GSS6700 simulation system to create a fully controlled environment to test and validate the developed method’s performance. The results demonstrated the proposed method’s capa...
Direction of Arrival Estimation of GPS Narrowband Jammers Using High-Resolution Techniques
GPS jamming is a considerable threat to applications that rely on GPS position, velocity, and time. Jamming detection is the first step in the mitigation process. The direction of arrival (DOA) estimation of jamming signals is affected by resolution. In the presence of multiple jamming sources whose spatial separation is very narrow, an incorrect number of jammers can be detected. Consequently, mitigation will be affected. The ultimate objective of this research is to enhance GPS receivers' anti-jamming abilities. This research proposes an enhancement to the anti-jamming detection ability of GPS receivers that are equipped with a uniform linear array (ULA) and uniform circular array (UCA). The proposed array processing method utilizes fast orthogonal search (FOS) to target the accurate detection of the DOA of both single and multiple in-band CW jammers. Its performance is compared to the classical method and MUSIC. GPS signals obtained from a Spirent GSS6700 simulator and CW jamming signals were used. The proposed method produces a threefold advantage, higher accuracy DOA estimates, amplitudes, and a correct number of jammers. Therefore, the anti-jamming process can be significantly improved by limiting the erroneous spatial attenuation of GPS signals arriving from an angle close to the jammer.