Differential synthetic aperture ladar

Stappaerts, E. A.; Scharlemann, E.T.

doi:10.1364/ol.30.002385

Cited by 17 publications

(5 citation statements)

References 6 publications

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“…Firstly, the positive and negative frequency modulation signals are divided into two sub-bands with the same time width in the range time domain. Performing differential interference calculation on each pair of positive and negative frequency modulation signals according to Equation (15), and extracting the Doppler phase introduced by motion error at the peak point of the range frequency spectrum. Then, based on the quality of scattering points, the differential interference phase is weighted average processing, and the interference phase at each azimuth moment is calculated through weighted average.…”

Section: Algorithm Flowmentioning

confidence: 99%

“…However, for the laser, the phase difference caused by motion errors between adjacent pulses may also differ greatly, so there is a risk of error accumulation in the process of extracting the interference phase. Stappaerts et al proposed a method of forward trajectory differential interferometry [15], which involves arranging multiple receiving channels in the azimuth direction and designing an algorithm to estimate motion errors using the phase information of the multi-channel received signals. However, this method requires adding multiple receiving channels in the system design, which increases system complexity.…”

Section: Introductionmentioning

confidence: 99%

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Synthetic Aperture Ladar Motion Compensation Method Based on Symmetric Triangle Linear Frequency Modulation Continuous Wave Segmented Interference

Shi,

Li,

Dong

et al. 2024

Remote Sensing

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Synthetic Aperture Ladar (SAL) is a sensor that combines laser detection technology with synthetic aperture technology to achieve ultra-high-resolution imaging. Due to its extremely short wavelength, SAL is more sensitive to motion errors. The micrometer-level motion will affect the target’s azimuth focus. This article proposes an SAL motion compensation method based on Symmetric Triangular Linear Frequency Modulation Continuous Wave (STLFMCW) segmented interference, utilizing the characteristics of a triangular wave, to solve the problem of target azimuth defocusing. This article first establishes an STLFMCW echo signal model based on the SAL system under the influence of motion errors. Secondly, the radial velocity gradient along the azimuth direction is extracted using the triangular-wave-positive and -negative frequency modulation signals segmented interference method. Then, for the initial phase wrapping problem, the frequency spectral cross-correlation method is used to accurately estimate the initial radial velocity error. The radial velocity gradient is integrated along the azimuth to obtain the platform motion trajectory. Finally, the compensation functions are constructed to complete the echo Range Cell Migration (RCM) correction and residual phase compensation, resulting in a focused SAL image. This article verifies the practical effect of this method in eliminating motion errors using only one-period STLFMCW signal through simulation and real experiments. The quantitative results show that compared with the traditional method, the proposed method reduces the azimuth Peak Sidelobe Ratio (PSLR) by 8dB and the Integrated Sidelobe Ratio (ISLR) by 9 dB. This method has significant improvements and is of great significance for high-resolution FMCW SAL imaging.

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Section: Algorithm Flowmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthetic Aperture Ladar Motion Compensation Method Based on Symmetric Triangle Linear Frequency Modulation Continuous Wave Segmented Interference

Shi,

Li,

Dong

et al. 2024

Remote Sensing

View full text Add to dashboard Cite

show abstract

“…A differential synthetic aperture ladar concept has been proposed. [10] In this paper, a phase differential algorithm (PDA) is presented to correct the phase error. For SAIL, the differential processing on the quadratic phase of the single point target echo can be given by ( )…”

Section: Introductionmentioning

confidence: 99%

Phase error correction by phase differential algorithm for synthetic aperture imaging ladar

et al. 2012

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During the signal acquisition for synthetic aperture imaging ladar, any phase error will deteriorate the phase-matched filtering results. The phase differential algorithm (PDA) is presented to correct the phase error. The quadratic spatial phase history can be reconstructed from the phase information submerged by the phase error from platform line-of-sight translation-vibration and nonlinear chirp. The theoretical modeling results and experimental results are presented.

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“…But when the working wavelength transit from microwave to optical wave, the transmission antenna and receive antenna become very sensitive to platform vibration and beam quality[2]. Through differential receive antenna formation, we can relax the requirement of platform and laser using synthetic aperture imaging ladar (SAIL) concept [3]. Line-of-sight motion constraints are reduced by several orders of magnitude.…”

mentioning

confidence: 99%

Three-dimensional imaging using differential synthetic aperture interferometry

et al. 2014

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Synthetic aperture radar interferometry (InSAR) can gain three-dimensional topography with high spatial resolution and height accuracy using across track interferometry [1]. Conventional InSAR produce three-dimensional images from SAR data. But when the working wavelength transit from microwave to optical wave, the transmission antenna and receive antenna become very sensitive to platform vibration and beam quality[2]. Through differential receive antenna formation, we can relax the requirement of platform and laser using synthetic aperture imaging ladar (SAIL) concept [3]. Line-of-sight motion constraints are reduced by several orders of magnitude. We introduce two distinctive forms of antenna formation according to the position of interferogram. The first architecture can simplify the interferogram processing and phase extraction algorithm under time-division multiplex operation. The second architecture can process the 2D coordinate and height coordinate at the same time. Using optical diffraction theory, a systematic theory of side-looking SAIL is mathematically formulated and the necessary conditions for assuring a correct phase history are established [4]. Based on optical transformation and regulation of wavefront, a side-looking SAIL of two distinctive architectures is invented and the basic principle, systematic theory, design equations and necessary conditions are presented. It is shown that high height accuracy can be reached and the influences from atmospheric turbulence and unmodeled line-of-sight motion can be automatically compensated.

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Differential synthetic aperture ladar

Cited by 17 publications

References 6 publications

Synthetic Aperture Ladar Motion Compensation Method Based on Symmetric Triangle Linear Frequency Modulation Continuous Wave Segmented Interference

Synthetic Aperture Ladar Motion Compensation Method Based on Symmetric Triangle Linear Frequency Modulation Continuous Wave Segmented Interference

Phase error correction by phase differential algorithm for synthetic aperture imaging ladar

Three-dimensional imaging using differential synthetic aperture interferometry

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