Related Experiment Video
Updated: Jul 14, 2026
15:25
Design and Characterization Methodology for Efficient Wide Range Tunable MEMS Filters
Published on: February 4, 2018
Fiber-based 1.5 microm lidar vibrometer in pulsed and continuous modes
Christopher A Hill1, Michael Harris, Kevin D Ridley
1Optronics Department, QinetiQ, St Andrews Road, Malvern WR14 3PS, UK. chill@QinetiQ.com
Applied Optics
|June 21, 2007
Summary
This study compares two modes of a fiber-based lidar for measuring target velocity. While pulse-pair lidar offers higher carrier-to-noise for wideband vibrations, continuous-wave lidar provides better overall signal-to-noise when measurements are combined.
Area of Science:
- Optical Engineering
- Remote Sensing
- Vibration Analysis
Background:
- Heterodyne lidar systems are crucial for remote sensing applications, including target velocity estimation.
- Switchable lidar modes, such as pulse-pair and continuous-wave (CW), offer different performance characteristics.
- Accurate measurement of target velocity and vibrational features is essential for various scientific and industrial applications.
Purpose of the Study:
- To compare the performance of pulse-pair and continuous-wave (CW) modes of a fiber-based heterodyne lidar.
- To evaluate the accuracy of Doppler frequency (target velocity) estimates and signal-to-noise ratio (SNR) for both modes.
- To investigate methods for combining CW measurements to improve vibration analysis.
Main Methods:
- Description of a fiber-based 1.5 µm heterodyne lidar system capable of switching between pulse-pair and CW modes.
- Laboratory experiments with controlled vibrating targets and computer simulations to assess lidar performance.
- Evaluation of Doppler frequency accuracy and SNR in spectrally resolved vibrational features.
- Application of autocorrelation-based demodulation to combine multiple CW measurements.
Main Results:
- Pulse-pair mode demonstrated higher carrier-to-noise ratio (CNR) when dealing with wideband target-induced frequency modulation.
- The advantage of pulse-pair mode in overall signal-to-noise ratio (SNR) was less pronounced due to the benefits of combining CW measurements.
- Autocorrelation-based demodulation improved the estimation of vibration frequencies and amplitudes from CW data, outperforming phase-differencing methods.
Conclusions:
- The choice between pulse-pair and CW lidar modes depends on the specific characteristics of the target's vibration.
- Combining multiple CW lidar measurements through advanced signal processing techniques like autocorrelation-based demodulation enhances the accuracy of vibration analysis.
- The developed fiber-based lidar system offers flexibility and improved performance for remote sensing of target dynamics.
