Radar Return Generator With I-Q Phasor Baseband Processing
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Solution Overview
Problem
Existing radar signal synthesis techniques suffer from distortion, particularly in phase, especially in airborne multi-mode radars that rely on accurate processing of differential Doppler, due to massive time-overlapping of return signals, which complicates the generation of high-fidelity radar images.
Innovation Solution
A radar return generator using I-Q phasors with in-phase (I) and quadrature (Q) components to represent impulse signals with a single non-zero sample, enabling accurate phase information and high-fidelity stimulation for any radar mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If finite impulse response (FIR) filtering is used to process massively overlapped return signals, then the radar system can handle time-overlapping signals, but phase distortion occurs which degrades image quality in airborne multi-mode radars
Solution Approach 1:
The patent changes the fundamental parameter representation from time-domain filtering to complex phasor representation. By representing impulse signals as complex numbers with magnitude and phase components, the system avoids time-domain filtering operations that cause phase distortion while preserving both amplitude and phase information accurately
Solution Approach 2:
The patent replaces the mechanical filtering process (FIR filtering) with a mathematical transformation approach using complex phasors. This substitution eliminates the need for iterative filtering operations that inherently introduce phase distortion, providing a direct computational method that preserves phase accuracy
2Device complexity
If traditional impulse signal representation is used, then the system structure is simple, but it cannot accurately convey phase information and cannot represent true impulses with zero width in time
Solution Approach 1:
The patent transitions from one-dimensional time-domain representation to two-dimensional complex plane representation. By using complex phasors with real and imaginary components, the system captures both magnitude and phase information simultaneously, effectively adding a dimensional aspect that enables accurate phase representation while maintaining computational efficiency
Data Source
AI summary
A radar stimulation system generates an intermediate-frequency (IF) radar return waveform for a radar receiver of a radar system under test (RUT) by applying down-conversion processing to a transmit IF pulse signal of the RUT to generate a transmit-side baseband I-Q signal having I-Q phasor signal samples with in-phase and quadrature components. I-Q convolutional processing is applied to the transmit-side baseband I-Q signal and synthesized net resultant vector (NRV) range traces to produce a return-side baseband I-Q signal, the synthesized net resultant vector (NRV) range traces representing a predetermined simulated radar scene, the convolutional processing including range-bin multiplexing of I-Q samples of the NRV range traces and I-Q finite-impulse-response (FIR) filtering using the I-Q phasor signal samples as filter coefficients. Up-conversion processing is applied to the return-side baseband I-Q signal to produce the synthesized IF radar return waveform.