High-resolution frequency-modulated continuous-wave laser ranging for precision distance metrology applications

Shi, Guang; Zhang, Fu‐Min; Qu, Xinghua

doi:10.1117/1.oe.53.12.122402

Cited by 44 publications

(14 citation statements)

References 11 publications

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“…The second scheme is to introduce an MZI with a long optical fiber as the auxiliary optical path 25 and extract the peak and valley points or zero-crossing points of the auxiliary optical path signal for equal frequency resampling the measurement signal, which can effectively eliminate the nonlinear problem of laser frequency sweeping after resampling. The final ranging result is positively related to the length of the long optical fiber, and the accuracy and stability of the long optical fiber also directly affect the accuracy of the ranging.…”

Section: ■ Introductionmentioning

confidence: 99%

High-Precision Silicon-Integrated Frequency-Modulated Continuous Wave LiDAR Calibrated Using a Microresonator

Zheng

Jia

et al. 2022

ACS Photonics

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Frequency-modulated continuous wave (FMCW) LiDAR can achieve long-distance and high-precision measurement, and the ranging error mainly comes from the nonlinearity of the laser frequency sweep. In this study, a high-precision silicon-integrated FMCW LiDAR is proposed. An equal frequency hypercube network is established by the stable free spectral range (FSR) of the microresonator to calibrate the nonlinearity of FMCW, and the distance matrix is obtained by analyzing the phase difference matrix of the FMCW signal. A standard length-based microresonator FSR calibration scheme is used to further improve the LiDAR accuracy. The feasibility of the scheme is verified by ranging and three-dimensional (3D) imaging. The ranging is carried out indoors and outdoors. In the indoor environment of a distance of 4 m, the minimum Allan deviation is 65 nm at 10.24 s. In the outdoor environment, the minimum Allan deviation at 438 m is 420 nm at 10.24 s. The 3D imaging can reconstruct the spatial point cloud of the objects and identify the spatial targets. This scheme has good on-chip integration capability and can be further combined with lens-assisted beam steering and optical phased array, laying the foundation for compact, large bandwidth, long-range, and high-precision LiDAR.

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Section: ■ Introductionmentioning

confidence: 99%

High-Precision Silicon-Integrated Frequency-Modulated Continuous Wave LiDAR Calibrated Using a Microresonator

Zheng

Jia

et al. 2022

ACS Photonics

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“…The dual-interferometers system is often adopted to deal with this issue for the phases of the beat signals in the two interferometers are proportional. Through sampling the measurement signal at every valley and peak point of the reference signal, the influence of nonlinear modulation of the laser can be solved [ 8 ]. The expression of the resampling signal can be obtained as follows:

where

represents the signal amplitude,

and

represent the time delay of the measurement and reference interferometers, and

stands for the number of the resampling points.…”

Section: Theoretical Principles and Modelsmentioning

confidence: 99%

“…Due to the influence of internal mechanical control accuracy, nonlinear creep, and the hysteresis effect, ideal linear modulation is hard to achieve in the actual modulation process, which will result in a serious reduction in the precision and resolution of ranging [ 8 ]. In order to solve this problem, a fiber reference interferometer is introduced into the system.…”

Section: Introductionmentioning

confidence: 99%

A Dispersion Compensation Method Based on Resampling of Modulated Signal for FMCW Lidar

Jiang

Liu

Wang

2021

Sensors

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In order to eliminate the nonlinearity in the laser modulation process, the dual-interferometers system is often adopted in the frequency modulation continuous wave (FMCW) laser ranging. However, the dispersion mismatch between the fiber reference interferometer and the measurement interferometer will lead to the decrease in ranging accuracy and resolution. In this paper, a dispersion compensation method based on resampling with a modulated signal is proposed. Since the beat signal of the end face of the delay fiber is not affected by dispersion mismatch, it can be modulated to generate a signal whose phase is proportional to that of the target spatial signal. Then, the modulated signal is regarded as the reference clock to sample the target spatial signal. Thereby, the influence of the dispersion mismatch between the two optical interferometers can be eliminated. In this article, simulation is performed to verify the effect of this method, and an experiment is carried out on the target at the distance of 2.4 m. Experiments show that the full width at half maximum (FWHM) of the distance spectrum after dispersion compensation is consistent with the reflected signal from the end face of the delay fiber, and the standard deviation of multiple measurements reached 10.12 μm.

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“…Furthermore, several algorithms are used to correct the nonlinear frequency sweeping [19,20]. Shi et al [21] resampled the beat signal in the measurement optical path with the peak-valley resampling method, which realized the linearization of the frequency ramp. The distance spectrum of the resampled signal was obtained by the fast Fourier transform (FFT), and the measurement precision was enhanced to 50 µm within 8.7 m. Liu et al [22] tracked the frequency of interference signal with an extended Kalman filter.…”

Section: Introductionmentioning

confidence: 99%

Phase Unwrapping and Frequency Points Subdivision of the Frequency Sweeping Interferometry Based Absolute Ranging System

Song

Shi

Liu

et al. 2022

Sensors

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Frequency sweeping interferometry (FSI) based absolute distance ranging has high precision and no ranging blind area. It can be used to realize large-scale and non-cooperative target measurement. However, the nonlinear frequency modulation of the laser seriously affects the ranging accuracy. In this manuscript, a measurement method assisted by Hilbert Transform (HT) and Chirp-z Transform (CZT) is proposed, which can realize the phase unwrapping of the beat signal, the length reduction in the delay fiber of auxiliary optical path, and the improvement of the frequency resolution. The narrow-band frequency suitable for HT is further studied. In the experiment, the ranging resolution is 70 μm and the standard deviation is 12.6 μm within a distance of 4005 mm.

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High-resolution frequency-modulated continuous-wave laser ranging for precision distance metrology applications

Cited by 44 publications

References 11 publications

High-Precision Silicon-Integrated Frequency-Modulated Continuous Wave LiDAR Calibrated Using a Microresonator

High-Precision Silicon-Integrated Frequency-Modulated Continuous Wave LiDAR Calibrated Using a Microresonator

A Dispersion Compensation Method Based on Resampling of Modulated Signal for FMCW Lidar

Phase Unwrapping and Frequency Points Subdivision of the Frequency Sweeping Interferometry Based Absolute Ranging System

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