Designing Constant Modulus Sequences with Good Correlation and Doppler Properties for Simultaneous Polarimetric Radar

Wang, Fulai; Pang, Chengxin; Li, Yongzhen; Wang, Xuesong

doi:10.3390/electronics7080153

Cited by 10 publications

(12 citation statements)

References 26 publications

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“…After a very careful peer-review process, a total of 32 papers were accepted. These works include SAR/ISAR [2][3][4][5][6][7][8][9], polarimetry [10][11][12], MIMO [13,14], direction of arrival (DOA)/direction of departure (DOD) [13][14][15], sparse sensing [5,14,16], ground-penetrating radar (GPR) [17][18][19], through-wall radar [20,21], coherent integration [22,23], clutter suppression [24,25], and meta-materials, among others [26][27][28][29][30][31]. All of these accepted papers are the latest research results and are expected to be further advanced, applied, and diverted.…”

Section: The Present Issuementioning

confidence: 99%

Special Issue on “Advanced Technology Related to Radar Signal, Imaging, and Radar Cross-Section Measurement”

Kobayashi

Moriyama

2020

Electronics

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Section: The Present Issuementioning

confidence: 99%

Special Issue on “Advanced Technology Related to Radar Signal, Imaging, and Radar Cross-Section Measurement”

Kobayashi

Moriyama

2020

Electronics

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“…Wang [201] and Palomer [202] have also proposed algorithms to reduce autocorrelation SLLs in an LCZ. Stoica and He in [171,203] have proposed CAs to reduce SLLs of both the autoand crosscorrelations, however, in an LCZ.…”

Section: Doppler Tolerant Code Optimisationmentioning

confidence: 99%

“…Stoica and He in [171,203] have proposed CAs to reduce SLLs of both the autoand crosscorrelations, however, in an LCZ. The most recent algorithm proposed in [201] also optimises codes for low auto-and crosscorrelation SLLs for Doppler tolerance in an LCZ.…”

Section: Doppler Tolerant Code Optimisationmentioning

confidence: 99%

“…All of these methods do not completely fulfil the requirements for an optimal set of codes for a multicode sonar system; flexibility in length n of codes [201], optimality in both the autoand crosscorrelations, optimising SLLs across the entire range of offsets for both auto-and crosscorrelations, optimal power profile and optimality for a range of Doppler shifts [204]. Some algorithms have only targeted code optimisation for Doppler shifts for periodic codes, which find limited application for a sensing application like a multicode sonar system.…”

Section: Doppler Tolerant Code Optimisationmentioning

confidence: 99%

“…Some designs proposed in the literature [201,249] have suggested mismatched filters to suppress higher SLLs due to the Doppler effect. These methods attempt to compensate for the degradation in the correlations due to the Doppler effect, but may not be effective for scenarios where the Doppler shift is neither predictable nor fixed.…”

Section: Mismatched Filter Designmentioning

confidence: 99%

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Code Optimisation Framework for Multicode Sonar Systems

Rashed¹

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<p>The ocean is a temporally and spatially varying environment, the characteristics of which pose significant challenges to the development of effective underwater wireless communications and sensing systems. An underwater sensing system such as a sonar detects the presence of a known signal through correlation. It is advantageous to use multiple transducers to increase surveying area with reduced surveying costs and time. Each transducers is assigned a dedicated code. When using multiple codes, the sidelobes of auto- and crosscorrelations are restricted to theoretical limits known as bounds. Sets of codes must be optimised in order to achieve optimal correlation properties, and, achieve Sidelobe Level (SLL)s as low as possible. In this thesis, we present a novel code-optimisation method to optimise code-sets with any number of codes and up to any length of each code. We optimise code-sets for a matched filter for application in a multi-code sonar system. We first present our gradient-descent based algorithm to optimise sets of codes for flat and low crosscorrelations and autocorrelation sidelobes, including conformance of the magnitude of the samples of the codes to a target power profile. We incorporate the transducer frequency response and the channel effects into the optimisation algorithm. We compare the correlations of our optimised codes with the well-known Welch bound. We then present a method to widen the autocorrelation mainlobe and impose monotonicity. In many cases, we are able to achieve SLLs beyond the Welch bound. We study the Signal to Noise Ratio (SNR) improvement of the optimised codes for an Underwater Acoustic (UWA) channel. During its propagation, the acoustic wave suffers non-constant transmission loss which is compensated by the application of an appropriate Time Variable Gain (TVG). The effect of the TVG modifies the noise received with the signal. We show that in most cases, the matched filter is still the optimum filter. We also show that the accuracy in timing is very important in the application of the TVG to the received signal. We then incorporate Doppler tolerance into the existing optimisation algorithm. Our proposed method is able to optimise sets of codes for multiple Doppler scaling factors and non-integer delays in the arrival of the reflection, while still conforming to other constraints. We suggest designing mismatched filters to further reduce the SLLs, firstly using an existing Quadratically Constrained Qaudratic Program (QCQP) formulation and secondly, as a local optimisation problem, modifying our basic optimisation algorithm.</p>

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Joint Optimization of Signal Waveforms and Filters for Long-Range MIMO Radars

Bezoušek

Karamazov

2022

IEEE Access

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This paper describes a cyclic algorithm for minimization of signal sidelobes and crosstalk in multiple-input multiple-output (MIMO) radar. The algorithm, called SWAP by the authors, is suitable mainly for long-range radars, such as ground-based surveillance, approach, or weather radar. The minimization of energy, minimization of side lobes, and crosstalk were used as the optimization criteria. Although the optimized signals do not maintain a strictly constant envelope, the peak-to-average power ratio (PAR) can be maintained below 1.7. This value is acceptable, especially for radars with modern transmitters based on GaN HEMTs. The algorithm allows for any arbitrary choice of elements weights, enabling the optimization of calculations for a wide range of applications. The effect of the Doppler shift can also be included in the optimization. This article also presents the results of algorithm testing under various conditions. The designed algorithm makes it possible to suppress the side lobes and crosstalk by up to 20 dB more than the matched filters. These results were achieved at the cost of a slight deterioration in signal-to-noise ratio (SNR) loss (less than 1 dB) and an increase in PAR (up to 2). The resolution of weak close targets is also slightly deteriorated. The algorithm converged quickly, and already after ten or 20 iterations, the results changed only minimally.

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Designing Constant Modulus Sequences with Good Correlation and Doppler Properties for Simultaneous Polarimetric Radar

Cited by 10 publications

References 26 publications

Special Issue on “Advanced Technology Related to Radar Signal, Imaging, and Radar Cross-Section Measurement”

Special Issue on “Advanced Technology Related to Radar Signal, Imaging, and Radar Cross-Section Measurement”

Code Optimisation Framework for Multicode Sonar Systems

Joint Optimization of Signal Waveforms and Filters for Long-Range MIMO Radars

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