High-resolution CW lidar altimetry using repeating intensity-modulated waveforms and Fourier transform reordering

Area of Science:

• Geospatial Science
• Optical Engineering
• Signal Processing

Background:

• Accurate range measurements are crucial for applications like altimetry.
• Intensity-modulated continuous wave (IM-CW) lidar systems require efficient signal processing for high-precision data acquisition.
• Existing methods for processing IM-CW lidar waveforms can be computationally intensive, limiting real-time applications.

Purpose of the Study:

• To introduce a novel interpolation method for processing repeating IM-CW lidar waveforms.
• To enable high-precision range measurements and altimetry.
• To facilitate real-time implementation of lidar data processing.

Main Methods:

• The method involves cross-correlation between transmitted and received IM-CW lidar signals.
• It utilizes reordering of array elements in the frequency domain to convert repeating synthetic pulses into a single, highly interpolated pulse.
• Computational complexity is minimally increased beyond the core correlation process.

Main Results:

• The developed interpolation method achieves high-precision range measurements.
• Flight-testing validated the method's viability for high-speed interpolated range measurements.
• A standard deviation of 0.75 m was achieved over water with 350 mW transmitted power at a range of 2600 m.

Conclusions:

• The described interpolation method is effective for high-precision range measurements using IM-CW lidar.
• The technique's computational efficiency allows for real-time applications.
• This advancement supports improved altimetry and other lidar-based remote sensing applications.