A comparison of two embedded programming techniques for high rep rate coherent Doppler lidars

Mark F. Arend; Sameh Abdelazim; Miguel Lopez; Fred Moshary

doi:10.1117/12.2016018

28 May 2013 A comparison of two embedded programming techniques for high rep rate coherent Doppler lidars

Mark F. Arend, Sameh Abdelazim, Miguel Lopez, Fred Moshary

Proceedings Volume 8731, Laser Radar Technology and Applications XVIII; 87310E (2013) https://doi.org/10.1117/12.2016018
Event: SPIE Defense, Security, and Sensing, 2013, Baltimore, Maryland, United States

Abstract

Two FPGA embedded programming approaches are considered and compared for a 20 kHz pulse repetition rate coherent Doppler lidar system which acquires return signals at 400 Msamples/second and operates with signal to noise ratios as low as -20 dB. In the first approach, the acquired return signal is gated in time and the square modulus of the fast Fourier transform is accumulated for each of the range gates, producing a series of power spectra as a function of range. Wind speed decisions based on numerical estimators can then be made after transferring the range gated accumulated power spectra to a host computer, enabling the line of sight wind speed as a function of range gate to be calculated and stored for additional processing. In the second FPGA approach, a digital IQ demodulator and down sampler reduces the data flow requirements so that an autocorrelation matrix representing a pre-selected number of lags can be accumulated, allowing for the process of range gating to be explored on the host computer. The added feature of the second approach is that it allows for an additional capability to adjust the range gate period dynamically as the state of the atmospheric boundary layer (e.g. backscatter coefficient and stability condition) changes. A simple manual beam scanning technique is used to calculate the wind field vector which is graphically displayed on time-height cross section plots. A comparison to other observed and modeled information is presented suggesting the usefulness for the characterization of microscale meteorology.

Citation Download Citation

Mark F. Arend, Sameh Abdelazim, Miguel Lopez, and Fred Moshary "A comparison of two embedded programming techniques for high rep rate coherent Doppler lidars", Proc. SPIE 8731, Laser Radar Technology and Applications XVIII, 87310E (28 May 2013); https://doi.org/10.1117/12.2016018

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