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.

Adaptive filtering algorithms can be used on the time-domain processing of navigation receivers to suppress interference and maintain the navigation and positioning function. The filter length can affect the interference suppression performance and hardware utilization simultaneously. In practical engineering, the filter length is usually set to a large number to guarantee anti-jamming performance, which means a high-performance receiver requires a high-complexity anti-jamming filter. The study aims at solving the problem by presenting a design method for the optimal filter order in the time-domain anti-jamming receiver, with no need for detailed interference information. According to interference bandwidth and jam-to-signal ratio (JSR), the approach designed a band-stop filter by Kaiser window for calculating the optimal filter order to meet interference suppression requirements. The experimental results show that the time-domain filtering processing has achieved good interference suppression performance for engineering requirements with optimal filter order in satellite navigation receivers.

Spoofing interference poses a significant challenge to the Global Navigation Satellite System (GNSS). To effectively combat intermediate spoofing signals, this paper presents an enhanced spoofing detection method based on abnormal energy of the quadrature (Q) channel correlators. The detailed principle of this detection method is introduced based on the received signal model under spoofing attack. The normalization parameter used in this method was the estimation of the noise floor. The performance of the proposed Q energy detector is validated through simulations, the Texas Spoofing Test Battery dataset and field tests. The results demonstrate that the proposed detector significantly enhances detection performance compared to signal quality monitoring methods, particularly in overpowered scenarios and dynamic scenarios. By increasing the detection probability in the presence of spoofing signals and decreasing the false alarm probability in the absence of spoofing signals, the proposed detector can better meet the requirements of practical applications.

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.

Interference mitigation is crucial for ensuring the reliability of Global Navigation Satellite System (GNSS) in complex electromagnetic environments. However, GNSS receivers frequently encounter various types of interference from radar, communication systems, airfields, and unmanned aerial systems. While existing interference mitigation methods for single-antenna GNSS receivers are only suppress specific types of interference. This paper proposes a multi-interference mitigation method based on the time-frequency Universal Network(TF-Unet) network. The TF-Unet method enables fine-grained segmentation based on high-resolution TF images, sensing and mitigating multidimensional interference features within TF domain. This method employs a signal fusion mechanism that optimizes interference mitigation by minimizing the TF Equivalent Mean Square Error (TFEMSE), thereby enhancing interference edge detection probability and reducing spectral impacts on GNSS signals. Leveraging high-resolution TF analysis, this approach constructs the first GNSS TF signal dataset encompassing multiple interference types and enables phase-aligned GNSS signal reconstruction. Simulations on both conventional and power-enhanced GNSS signals demonstrate that the proposed method effectively suppresses narrow-band interference (NBI), linear frequency sweeping interference (LFSI), and pulse interference (PI) by maximum 10dB·Hz carrier-to-noise ratio(C/N₀) gain compared to conventional methods. Practical experimental further validated that the positioning accuracy can be improved by 27%.

With the development of global navigation satellite systems, the modernization of global navigation satellite systems has arrived, which takes the binary offset carrier modulation and related evolution as the typical feature. Moreover, the performance of multiplexed binary offset carrier modulation is related to global navigation satellite systems service. In the paper, an improved multiplexed binary offset carrier modulation based on period offset subcarrier was proposed, called MBOC‐POS, where the subcarrier periodic shifting binary offset carrier modulation is used as the lower‐order component instead of sine‐binary offset carrier modulations. Meanwhile, the different implementations of MBOC‐POS modulations are analysed and compared with traditional multiplexed binary offset carrier multiplexed binary offset carrier signals in multipath mitigation, tracking accuracy, anti‐interference and compatibility. By simulation and analysis, the performance of reconstructed MBOC‐POS modulation has been improved. Especially, for the mismatch reception, the Gabor bandwidth increases by 29.5% and the multipath error envelope is reduced by 35% with the filter bandwidth of 10 MHz. Therefore, the multiplexed binary offset carrier MBOC‐POS modulation proposed in the paper can be used as a new option for MBOC modulations and next‐generation signal design.