摘要 :
Synthetic impulse and aperture radar (SIAR) is a multi-input multi-output orthogonal multicarrier frequency radar, kind of frequency diverse array (FDA). This radar has omnidirectional emission in the transmitter and each receiver...
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Synthetic impulse and aperture radar (SIAR) is a multi-input multi-output orthogonal multicarrier frequency radar, kind of frequency diverse array (FDA). This radar has omnidirectional emission in the transmitter and each receiver or receiving array can form a beam. The 4D matched filter of this radar’s circular arrays can reveal the range, elevation angle, azimuth angle, and Doppler. The existence of a high sidelobe in the range-Doppler is one of the significant challenges of this radar, and pulse-to-pulse frequency code non-agile (PPFCNA) and pulse-to-pulse frequency code agile (PPFCA) are often used to reduce it. Weighting is one of the available methods for reducing sidelobes in array radars, but weighting in the matched filter is more effective in SIAR radars due to their ability to transmit signals with different and orthogonal frequencies. This paper proposes the use of amplitude weighting in the submatched filter, which is made possible by increasing the degree of freedom in the SIAR process. In this method, each receiver’s signal is independently processed and weighted with a submatched filter. Then, a synthetic pulse is formed by combining the data from multiple channels. The output of the simulation with weighting in the matched filter for the PPFCNA indicates an 8.7908 dB reduction in sidelobes, while the output for the PPFCA indicates a 3.3779 dB reduction in sidelobes.
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摘要 :
Synthetic Impulse and Aperture Radar (SIAR) is a kind of Multiple Input Multiple Output (MIMO) radar. It is a four‐dimensional radar that has advantages against stealth targets, multi targets, anti‐radiated missile, reconnaissan...
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Synthetic Impulse and Aperture Radar (SIAR) is a kind of Multiple Input Multiple Output (MIMO) radar. It is a four‐dimensional radar that has advantages against stealth targets, multi targets, anti‐radiated missile, reconnaissance and interference, as well as valuable features in high range resolution and high detection probability. SIAR uses special frequency coding separately in each antenna. This code has an essential function in SIAR, such as separating frequency bandwidth, satisfying orthogonality in transmitted signals, suppressing range‐angle and range‐Doppler frequency coupling. Pulse‐to‐pulse frequency code agility is a kind of radar signal coding that is used to suppress the sidelobes in range‐Doppler frequency. In this study, a design method is suggested to transmit waveform based on non‐sequential positive, negative and random carrier frequency coding with the dot product approach in pulse‐to‐pulse frequency code agility, to reduce sidelobes in range‐Doppler frequency coupling. The simulation results showed that this method could effectively remove the strong coupling between range‐Doppler frequency. Removing coupling in the range‐Doppler frequency decreases the sidelobes.
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摘要 :
Synthetic impulse and aperture radar (SIAR) is an orthogonal multiple input multiple output radar. It has several advantages, including the ability to detect multiple targets, Antiradiated Missiles (ARM), and stealth targets. Desp...
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Synthetic impulse and aperture radar (SIAR) is an orthogonal multiple input multiple output radar. It has several advantages, including the ability to detect multiple targets, Antiradiated Missiles (ARM), and stealth targets. Despite its four-dimensional (4-D) nature, it exhibits a strong coupling between range and angle, which dictates how well SIAR performs in the range-angle domain. Not only does the SIAR use frequency codes to separate the antennas, but also to ensure orthogonality. They can, however, mitigate the strong coupling between range and angle. Pulse-to-pulse frequency code agility is a technique for suppressing the SIAR radar's sidelobes. In this letter, we propose a method for reducing the coupling between range and angle by combining sequential positive, negative and random code with the dot product. The idea of coupling reduction presented in this letter is based on the ratio of each antenna position and frequency codes, which is referred to $\alpha $k, and multiple $\alpha $k in an array provides new advantages for target detection. This technique has the potential to significantly reduce the sidelobe levels.
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