Coherent Doppler LIDAR with long-duration frequency-modulated pulses for wind sensing

Area of Science:

• Atmospheric Science
• Optical Remote Sensing

Background:

• Traditional coherent Doppler LIDAR (CDL) systems using short-duration single-frequency pulses (PCDL) face a trade-off between distance and velocity resolution.
• A theoretical framework for frequency-modulated CDL (FMCDL) using long-duration frequency-modulated pulses was previously proposed to overcome this limitation.

Purpose of the Study:

• To demonstrate and validate a coherent Doppler LIDAR (CDL) prototype capable of operating with both pulsed (PCDL) and frequency-modulated (FMCDL) long-duration pulses.
• To experimentally verify the theoretical advantages of FMCDL in eliminating the distance-velocity resolution trade-off.

Main Methods:

• Development of a prototype CDL system configurable for both PCDL and FMCDL operation.
• Comparative analysis of data acquired by the prototype in both PCDL and FMCDL modes for wind ranging and velocimetry.
• Quantitative assessment of FMCDL performance metrics, including received power and resolution, against theoretical predictions.

Main Results:

• The FMCDL mode of the prototype demonstrated effective wind ranging and velocimetry, showing good agreement with the PCDL mode.
• Experimental results quantitatively confirmed the theoretically expected performance of the FMCDL, particularly regarding received power and resolution.
• The FMCDL successfully operated without the inherent distance-velocity resolution trade-off characteristic of PCDL.

Conclusions:

• The developed FMCDL prototype successfully validated the theoretical framework, proving its capability to eliminate the distance-velocity resolution trade-off.
• FMCDL offers a promising advancement in Doppler LIDAR technology for accurate and high-resolution atmospheric measurements.
• The system's performance in received power and resolution aligns with theoretical expectations, paving the way for practical applications.