Antenna arrays equipped with space‐time adaptive processors (STAPs) are effective to maintain the integrity and functionality of global navigation satellite systems (GNSSs) in various applications. However, one of the major problems with existing space‐time processing methods is that they can introduce significant biases into the GNSS receiver measurements. A distortionless STAP is proposed. It could not only suppress the interfering signals and enhance the GNSS signals, but also introduce no biases into the code and carrier phase measurements. The key idea behind the proposed method is ensuring linearity of the space‐time processor response by constraining its coefficients. The effectiveness of the proposed method is verified by theoretical analysis and simulation results.

In recent years, Global Navigation Satellite System (GNSS) spoofing detection techniques have attracted wide attention. Spoofing attacks have posed a greater security threat than jamming and are more difficult to detect due to their strong concealment. One of the key measurements of GNSS instruments is the carrier-to-noise ratio (C/N ₀ ), which may be affected by spoofing. However, the variations in C/N ₀ are always uncertainty especially for the array instruments under the attack. This paper proposes a method for GNSS array instruments to detect the spoofing after anti-jamming. A theoretically model of the effective C/N ₀ in array receiver is deduced. The C/N ₀ Single Difference (CSD) between satellites is further proposed as a testing statistic for spoofing detection. Simulation results demonstrate that the proposed method can effectively detect the abnormal C/N ₀ feature of counterfeit signals after anti-jamming by the antenna array. The detection performance of the proposed metrics is verified in the jamming and spoofing scenarios using the real data collected by an antenna array instrument. This method does not require modifications to the hardware configuration of conventional array receivers and can provide an effective defense in the combination of jamming and spoofing attacks.

Radio frequency interference has become a rising problem to the signal of the Global Navigation Satellite System (GNSS). An effective way to achieve anti-jamming is by using an antenna array in GNSS signal processing. However, antenna array processing will cause a decline in the accuracy of pseudo-range measurements because of the channel mismatch and some other non-ideal factors. To solve this problem, space–time or space–frequency adaptive array processing is widely used for interference cancellation while constraining the delay of each antenna at the same time. In this paper, an anti-jamming algorithm with a time-delay constraint is proposed, where one antenna is chosen as the reference and data from other antennas is corrected based on the signal received from it. The deduction and simulation results show that the proposed algorithm can effectively improve the accuracy of pseudo-range measurements without degradation of anti-jamming performance.

Signal acquisition has become the performance bottleneck of global navigation satellite systems (GNSS) receivers in harsh interference environments due to its low sensitivity. In this Letter, a novel anti‐jamming algorithm based on the minimum mean square error criterion is proposed to protecting the acquisition stage. The key idea behind the proposed method is that the grid search process of synchronisation parameters is shared by both interference suppression and signal acquisition. Simulation results indicate that the proposed method is capable of maintaining the functionality of GNSS receivers at cold start in the presence of interfering signals. In addition to this, its performance outperforms the power inversion method significantly.

Low-Earth-Orbit (LEO) satellite Signal-of-Opportunity (SOP) positioning technology has gradually matured to meet the accuracy requirements for unmanned aerial vehicle (UAV) positioning in daily scenarios. Advancements in miniaturization technology for positioning terminals have also made this technology’s application to UAV positioning crucial for UAV development. However, in the increasingly complex electromagnetic environment, there remains a significant risk of degradation in positioning performance for UAVs in LEO satellite SOP positioning due to unintentional or malicious jamming. Furthermore, there is a lack of in-depth research from scholars both domestically and internationally on the anti-jamming capabilities of LEO satellite SOP positioning technology. Due to significant differences in the downlink signal characteristics between LEO satellites and Global Navigation Satellite System (GNSS) signals based on Medium Earth Orbit (MEO) or Geostationary Earth Orbit (GEO) satellites, the anti-jamming research results of traditional satellite navigation systems cannot be directly applied. This study addresses the narrow bandwidth and high signal-to-noise ratio (SNR) characteristics of signals from LEO satellite constellations. We propose a Consecutive Iteration based on Signal Cancellation (SCCI) algorithm, which significantly reduces errors during the model fitting process. Additionally, an adaptive variable convergence factor was designed to simultaneously balance convergence speed and steady-state error during the iteration process. Compared to traditional algorithms, simulation and experimental results demonstrated that the proposed algorithm enhances the effectiveness of jamming threshold settings under narrow bandwidth and high-power conditions. In the context of LEO satellite jamming scenarios, it improves the frequency-domain anti-jamming performance significantly and holds high application value for drone positioning.

In recent years, Global Navigation Satellite System (GNSS) spoofing detection techniques have attracted wide attention. Spoofing attacks have posed a greater security threat than jamming and are more difficult to detect due to their strong concealment. The antenna array has proved to be an effective means of spoofing detection utilizing the direction of arrival (DOA) estimation. However, such approach remains a major challenge since the uncertainty in the attitude estimation and antenna array calibration. This paper proposes a method for GNSS array receivers to detect the spoofing without affecting the mitigation to high-power interference. The double difference of carrier phase (DDCP) produced by adding the auxiliary reference element (ARE) processing is further proposed as a testing statistic for spoofing detection. Simulation and experiment results are given to demonstrate the detection performance of the proposed metrics. The method does not require the DOA estimation or array calibration, but is flexible to implement using the observed measurements and can provide an effective defense in the combination of jamming and spoofing attacks.