The first step in marine navigation radar anti-interference is hardware optimization. In antenna design, high-gain, narrow-beam antennas are used to accurately control the radiation direction of radar waves, reduce lateral coupling interference from other equipment signals, and enhance the ability to capture target echo signals. In the radar transmitter part, power stabilization technology and shielding measures are used to ensure the stability of its own transmission signal and avoid self-interference caused by power fluctuations; on the other hand, the transmitter is electromagnetically shielded to prevent the leakage of stray signals generated by the internal circuit, which interfere with other equipment or are counter-interfered by other signals. In addition, components with strong anti-electromagnetic interference performance, such as low-noise amplifiers and filters with excellent filtering performance, are selected to reduce the impact of interference signals from the hardware source.
Frequency agility technology is an effective means to deal with complex electromagnetic interference. In sea areas with complex electromagnetic environments, radars can avoid fixed interference frequencies of other devices by changing the operating frequency quickly and randomly. When the radar detects a strong interference signal at a certain frequency, it quickly switches to other available frequencies to continue working, making it difficult for the interference source to lock the radar's operating frequency for targeted interference. At the same time, frequency agility technology can also effectively combat co-frequency interference. By transmitting and receiving signals on multiple frequencies, the echo signals are comprehensively processed to identify the real target signal, eliminate the influence of interference signals, and improve the detection accuracy of radar in complex environments.
Advanced signal processing algorithms provide software-level support for anti-interference. The adaptive filtering algorithm can automatically adjust the filtering parameters according to the characteristics of the real-time received signal to suppress the interference signal while retaining the real target signal. For example, for sea clutter interference, the statistical characteristics of sea clutter are analyzed and the adaptive filtering algorithm is used to remove the clutter and highlight the target echo. In addition, the algorithm combining pulse compression and Doppler processing can perform fine processing on the radar echo signal. Pulse compression technology improves the range resolution of the radar and distinguishes different targets at close range; Doppler processing uses the Doppler frequency shift generated by the relative motion of the target and the radar to identify the moving target and filter out the stationary interference, thereby accurately extracting the target information in a complex electromagnetic environment.
Polarization technology uses the difference in polarization characteristics between the target and the interference signal to achieve interference suppression. Marine navigation radar can use variable polarization antennas to adjust the polarization of transmitted and received signals in real time according to different interference environments and target characteristics. For example, when encountering horizontally polarized interference signals, the radar switches to vertical polarization to transmit and receive signals. Since the interference signal and the radar signal have different polarization modes, most of the interference energy cannot be received by the radar, thereby effectively suppressing the interference. In addition, through polarization diversity technology, signals of multiple polarization modes are transmitted and received at the same time, and the echo signals are comprehensively analyzed to enhance the detection capability of targets with different polarization characteristics, and improve the radar's anti-interference performance and target recognition capability in complex electromagnetic environments.
A single marine navigation radar has limitations in complex electromagnetic environments, and multi-sensor data fusion has become an important way to improve reliability. Combine radar with other navigation equipment, such as the global positioning system (GPS), electronic chart display and information system (ECDIS), automatic identification system (AIS), etc., and use data fusion algorithms to comprehensively process the information obtained by each sensor. When the radar is interfered with and the signal is inaccurate, the position, speed, heading and other information provided by other sensors can be used for auxiliary judgment, mutual verification and supplementation, reduce dependence on a single radar signal, and improve the overall reliability and anti-interference ability of ship navigation.
To ensure the effectiveness of the anti-interference design, the marine navigation radar needs to be strictly tested and optimized. In the laboratory environment, various complex electromagnetic interference scenarios are simulated, such as strong electromagnetic pulse interference, co-frequency continuous wave interference, etc., the anti-interference performance of the radar is comprehensively tested, and the impact of interference on performance indicators such as radar detection distance and target recognition is analyzed. According to the test results, the hardware parameters and software algorithms are adjusted and optimized in a targeted manner. In actual applications, the operation data of the radar in different sea areas and different electromagnetic environments are collected, and the anti-interference design is continuously improved so that the radar can better adapt to the complex and changeable electromagnetic environment and ensure the safety of ship navigation.
With the continuous development of electronic technology, the anti-interference technology of marine navigation radar is also continuously innovating. The application of artificial intelligence and machine learning technology will become a future trend. By learning a large amount of interference signal and target signal data, the radar can automatically identify the type of interference and adaptively adjust the anti-interference strategy to achieve more intelligent interference suppression. In addition, the development of cognitive radar technology enables radar to perceive the surrounding electromagnetic environment in real time, autonomously adjust working parameters and signal processing methods, further improve anti-interference capabilities and target detection performance in complex electromagnetic environments, and provide more reliable protection for ship navigation.
