ISAR Imaging Based on the Wideband Hyperbolic Frequency-Modulation Waveform

Area of Science:

• Radar Systems Engineering
• Signal Processing
• Electromagnetics

Background:

• Hyperbolic frequency-modulated (HFM) waveforms offer inherent Doppler-invariance, advantageous for high-speed moving target imaging.
• Conventional linear frequency-modulated (LFM) waveforms are less suitable for such applications.
• Existing inverse synthetic aperture radar (ISAR) systems require adaptation for HFM waveform utilization.

Purpose of the Study:

• To propose a novel pulse compression algorithm for integrating HFM waveforms into existing ISAR imaging systems.
• To facilitate high-speed moving target imaging using the Doppler-invariant properties of HFM waveforms.
• To enhance the applicability of HFM waveforms in practical ISAR scenarios.

Main Methods:

• A 'decurve' process demodulates received HFM echoes, reducing bandwidth for narrow-band receiver compatibility.
• Pulse compression is achieved through space-variant phase compensation on the decurved HFM echoes.
• Efficient implementation of space-variant phase compensation is performed using resampling and fast Fourier transform (FFT).

Main Results:

• The proposed algorithm effectively reduces the bandwidth of HFM echoes.
• Space-variant phase compensation successfully achieves pulse compression.
• Numerical simulations validate the effectiveness of the developed HFM pulse compression method.

Conclusions:

• The novel pulse compression algorithm enables the effective use of HFM waveforms in ISAR systems.
• The method addresses the challenge of processing wide-bandwidth HFM signals with existing narrow-band receivers.
• This advancement improves ISAR capabilities for imaging high-speed moving targets.