The satellite navigation signals have inherent vulnerabilities and are highly susceptible to both intentional and unintentional electromagnetic interference. Therefore, conducting monitoring and evaluation of satellite navigation service performance and interference signals is of significant importance for supporting the operational services of navigation systems and ensuring the security of spatio-temporal information applications. This paper addresses the mechanisms and characteristics of monitoring and evaluating satellite navigation service performance. In conjunction with the practical needs for interference monitoring and troubleshooting, it presents an overall architecture for system construction and operational processes. Furthermore, it conducts research and analysis on the key technologies necessary for enhancing system effectiveness, providing comprehensive guidance and technical support for the engineering construction of a navigation application monitoring and support system characterized by “multi-source integration, wide-area coverage, three-dimensional perception, and rapid response”.
Satellite internet provides positioning, navigation and timing services for the whole world based on the Global Navigation Satellite System (GNSS), but the data containing users’ location information will be leaked during GNSS cooperative positioning process, which poses a threat to users’ privacy security. To address the current privacy-protection challenges in GNSS cooperative positioning systems, this paper proposes a differential privacy-based cooperative positioning method for GNSS systems. The method first generates the perturbed position and randomly selects one to calculate the positioning collaboration data under the premise of satisfying the privacy budget, so as to prevent the user’s location from being leaked during the collaboration process. The experimental results show that the proposed method can effectively protect user location privacy while guaranteeing real-time and accurate positioning service, which provides a theoretical reference for the research of GNSS cooperative positioning information security.
Satellite navigation has been widely used in various fields of human production and life, however, due to weak landing signals and other reasons, satellite navigation signals are prone to interference. In practical applications, distributed suppression jamming has become an effective means of satellite navigation jamming because of its advantages such as large coverage area and difficult detection. In this paper, the visual field algorithm based on the reference surface is used to calculate the interference range of a single jamming station in a specific terrain, and on this basis, a cyclic iterative method is used to find the optimal layout scheme of distributed jamming suppression. Experimental analysis shows that under experimental conditions, the distributed suppression interference coverage rate of the proposed method is more than 98%, which is obviously better than 74.18% of the traditional high-power single interference source. At the same time, the key suppression interference targets can be further highlighted and multiple suppression interference can be realized by setting red and green zones reasonably.
Traditional maritime rescue terminals suffer from insufficient positioning accuracy and real-time performance. A maritime rescue terminal is designed for combines the functions of BDS short message and Emergency Position Indicating Radio Beacons (EPIRB). Combined with the command center and related software systems, it can achieve rapid reporting and precise positioning of distress. BeiDou Navigation Satellite System (BDS) short message communication can send messages between terminals and satellites. The COSPAS-SARSAT is an important component of the maritime distress search and rescue system implemented by the International Maritime Satellite Organization. It uses signals sent by EPIRB to locate accident locations and information. Combine the BDS short message with EPIRB, and assemble positioning modules and temperature, heart rate, and other sensors. When the holder is in danger, the terminal will immediately continuously send distress information to the command center, which can provide support for the rescue mission through analysis by the command center. After testing, its dynamic and static positioning accuracy has reached the level of 10 meters; BDS short message, EPIRB working well.
The carrier to noise ratio (CNR) based interference positioning in Global Navigation Satellite System (GNSS) has the problem of high localization difficulty and the low localization precision under the scenarios with multiple interference sources, multi-path transmission and long distance between receivers. Aiming at this problem, a multi-interference localization scheme that combines the weighted K-Means clustering with different receiver signal strength (DRSS) and equation solving based method is proposed in this paper. Assuming that the number of interference sources is determined and a single receiver is only affected by one interference source, the improved weighted K-Means clustering algorithm is designed to realize the initial estimation for multiple interference sources. In order to reduce the positioning error of the weighted K-Means clustering when the distance between receives is long, the receiving CNR affected more obviously by interference within each cluster are used to build the localization equations based on DRSS after clustering processing. To solve the equations can obtain the more accurate localization results. Simulation results demonstrate that the proposed scheme can realize the multi-interference localization. Compared with the scheme only including weighted K-Means, the average positioning errors of the proposed method involving DRSS parameters can be reduced by more than 19% and 38% under the two cases of single source and two single-tone sources, respectively.
Global Navigation Satellite System (GNSS) is widely used in all walks of life. However, GNSS signals are very weak and the civilian signal format is known, making it extremely susceptible to various intentional and unintentional electromagnetic interferences, which poses a serious threat to GNSS applications. GNSS interference has attracted widespread international attention, the International Committee on Global Satellite Navigation Systems (ICG) has established a special GNSS interference detection and mitigation (IDM) working group to develop IDM technologies and exchange ideas on IDM system construction. This paper introduces the situation of ICG IDM, and analyzes the research progress of GNSS interference detection and localization technology and IDM systems. It provides important technical reference and research support for deepening the theoretical and technical research on GNSS interference monitoring and ensuring the safety of satellite navigation.
The Russia-Ukraine Conflict is one of the major hotspot of the international situation. This paper reviews the situation of Russia and Ukraine navigation countermeasure equipment. Based on the IGS monitoring data near the conflict area and the military actions of Russia and Ukraine, this paper analysis the measures taken by Russia and Ukraine to fight for control of navigation resources in the conflict, and deeply studied the application methods of navigation confrontation between the two sides. Through analysis, it can be concluded that satellite navigation signals in conflict zones are one of the important sources of battlefield intelligence. Combined with other reconnaissance methods, comprehensive analysis and judgment can comprehensively reflect the military dynamics of the battlefield.
Due to the low signal strength of GNSS signals upon reaching the ground, they are highly susceptible to unintentional or intentional human interference, which can severely impact the availability of navigation and positioning services. Therefore, locating and eliminating sources is of paramount interference. For common jamming interference, current positioning methods mainly involve processing the raw sampled signals, which often leads to issues with complex equipment, high computational demands, and high costs. This paper proposes a method for locating GNSS interference source using the carrier-to-noise ratio (C/N0) measurements from standard commercial receivers. By estimating the interference signal strength difference through C/N0 measurements, the position of the interference source can be calculated. Field test results indicate that, under line-of-sight conditions, in a monitoring area of approximately 11 400 square meters, this method can achieve a Mean Absolute Error (MAE) of 13.17 meters with minimal time consumption, thereby effectively locating the interference source. The proposed method does not require any modifications to the receiver's hardware or software, making it simple to implement and cost-effective, which is advantageous for engineering applications.
This paper analyzes the security advantages of radio determination satellite service (RDSS) in terms of signal structure and operation mechanism, and studies the potential security risks and countermeasures of RDSS from three aspects of information security: confidentiality, integrity, and availability. In particular, the use of radio frequency recording and replay (RAR) to verify the potential counterfeiting and deception security risks of RDSS has been studied prove that RDSS has vulnerabilities in resisting RAR attacks and is easily deceived by RAR attacks. The success of this deception attack exposes the security risks in the integrity and availability of the RDSS system, which can cause information confusion for end users and may also limit the frequency of attacks, preventing them from receiving normal services. Finally, several measures were proposed to improve system security in response to such security risks.
The Global Navigation Satellite System (GNSS) and inertial navigation system (INS) are widely used in fields such as vehicles and drones. However, GNSS receivers are susceptible to deceptive signals. Therefore, this paper proposes a consistency deception detection technique using INS observations. Inertial devices have the characteristics of being less susceptible to deceptive signal interference and prone to cumulative errors. By alternately feeding back estimated errors in an open-closed loop manner, a GNSS/INS integrated navigation system is constructed. During the open-loop period, a deception detection window is established, and the consistency between the statistical detection measurements of the inertial device, acceleration, and angular velocity obtained from GNSS is evaluated to determine the presence of deception. Experimental results demonstrate that with a window time of 70 s, the detection probability reaches 99.2% while the false alarm probability is 5.2%.
The Global Navigation Satellite System (GNSS) plays a strategic role in positioning, navigation, and timing in infrastructure application. Given the characteristics of GNSS signals such as extremely low landing power and transparent civil code structure, civil satellite signals are extremely vulnerable to interference and spoofing attacks, which makes GNSS suffer from serious interference problems. In this paper, to address the problems of low detection probability and poor reliability of traditional SQM (signal quality monitoring) detection quantities, we propose a new type of SQM detection quantities without the carrier phase information of tracking loop. Then, the metric values are moving averaged to reduce the effect of abnormal fluctuation value on the false alarm probability. Besides, the statistical distribution characteristic of the proposed metric is derived. The computation threshold and measurement threshold without a priori information are set up. The proposed method can avoid the failure detection when the relative carrier phases of spoofing and authorized satellite navigation signal are integer multiples of π. The comparison experimental results based on the public database with real measured signals of TEXBAT (texas spoofing test battery) show that the proposed algorithm is able to detect spoofing attacks with better accuracy in a shorter time under different real signal scenarios. The research results are valuable for the development of anti-spoofing communication devices in the future to improve the detection performance effectively without making large-scale changes to the hardware structure of the receiver.
Global Navigation Satellite System (GNSS) civil signals are vulnerable to external spoofing because of their openness and vulnerability. As an effective method for spoofing detection, Signal Quality Monitoring (SQM) monitors the correlation results of early code, late code and phase code (ELP) after the receiver's tracking loop, and compares them with the correlation characteristics without spoofing to determine whether spoofing interference exists. The conventional SQM algorithm uses only three ELP information and the detection performance is limited. Therefore, a multi-correlator combined power algorithm is proposed. The weight of the output power of multiple equally spaced correlators between ELP is taken as the detection quantity, and the inverse ratio of the correlation time and the real-time code time difference is taken as the weighting coefficient. The probability distribution characteristics of the detected quantity were further analyzed, and the optimal detection threshold was determined based on the Neyman-Pearson theory. By comparing the detected quantity and the detection threshold, the existence of deception interference was determined. Based on the Scenario 4 set published by the University of Texas, the test results show that compared with typical SQM algorithms such as Ratio and ELP, the proposed algorithm has both high detection probability and fast early warning response time under different false alarm rates.
Global navigation satellite systems play an important role in national infrastructure as well as life safety applications, but the increasing spoofing incidents pose a great threat to GNSS. This paper introduces the anti-spoofing technology based on array antenna signal processing, and summarizes the spoofing interference detection and spoofing interference suppression methods from both uniform and sparse arrays according to the different array configurations. Compared with uniform array, sparse array has larger array aperture and degree of freedom under the same number of antenna elements, which greatly reduces the cost of equipment, but its coherent signal processing technology requires more. Finally, this paper gives the difficulties faced by the anti-spoofing interference technology and its future development trend.
Temporal and spatial information security is fundamental to the safety of national critical infrastructure. Disruption or interference with the time system can cause significant economic losses to the nation, and even pose a substantial threat to defense security. Existing timing deception detection methods primarily establish models based on the characteristics of changes in the receiver’s clock model to detect deception. However, due to the uncertainty of attack methods and the system errors inherent in the established receiver clock model calculation and fitting process, accurate fitting of the clock model parameters is difficult, and the environmental adaptability is low. To address this, this paper proposes a timing deception detection method based on the Long Short-Term Memory (LSTM) network. This method does not require consideration of the attack methods of timing deception, and has strong generalization capabilities. By utilizing the excellent time series prediction ability of LSTM, the method accurately tracks the trend of changes in receiver clock differences before and after timing deception based on the characteristics of these changes, achieving effective detection of timing deception interference. Finally, experiments and analyses are conducted using TEXBAT (Texas spoofing test battery) timing deception scenario data, and a comparison is made between LSTM and Multilayer Perceptron (MLP) networks. The results indicate that the performance of LSTM timing deception detection is superior to that of MLP.
A spoofing detection algorithm based on power combind with signal quality montoring(PCS) combind with Ratio(PCSR) is proposed to improve the performance of spoofing detection, in response to the problem of high fluctuation in the detection performance of PCS during the traction stage. The fusion process of the PCSR algorithm uses a weighting factor to linearly weight the amplitudes of the processed PCS and Ratio, and adjusts the contribution of PCS and Ratio to PCSR by changing the weighting factor.The experiment used data scenario 4 (DS4) of texas spoofing test battery (TEXBAT) from the University of Texas at Austin as the dataset to compare and analyze the deception detection performance of PCS, Ratio, and PCSR algorithms. The experimental results show that PCSR has higher detection probability and accuracy, better immediacy and robustness, and a wider detection range. The proposed PCSR algorithm combines the advantages of both PCS and Ratio algorithms and has better spoofing detection performance.
In view of the increasingly vicious UAV “black flight” phenomenon, and considering that its satellite navigation terminal will be loaded with multi-array adaptive zeroing anti-jamming antenna to improve the use of navigation resources, the advantages of using satellite navigation jamming for UAV defense are analyzed, and a satellite navigation jamming method for UAV defense is explored. The implementation strategy of navigation jamming from single interference source to multi-interference source is described, and the evaluation index is given. It helps protection personnel to accurately explore effective defense boundaries, determine weak areas, optimize interference source deployment strategies, and improve protection efficiency. A defense effect evaluation software is developed, which can present the defense situation and make the defense effect display more intuitive.
Bimonthly, Established 1976
Sponsored by:China Institute of Radio Transmission
Competent Authorities:China Electronics Technology Group Corporation
ISSN 1008-9268
CN 41-1317/TN
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