Design and development of a detection chain for an atmospheric lidar system

LIDAR systems are used in many atmospheric research applications. They consist mainly of a transmitting subsystem that emits a pulsed laser beam into the atmosphere and a receiving subsystem for laser backscattered signal detection and analysis. Many of these atmospheric applications requires high accuracy LIDAR systems, which is the focus of this article. In this paper, we provide information on the basic characteristics and performance of a detection chain for a LIDAR system used in remote sensing of the atmosphere. The detection chain, which is characterized by its low-cost and low-power consumption, allows high spatial and temporal resolution, reliable operation and wide dynamic range: A fast, low noise and high efficiency photodetector used in analog mode convert the detected optical backscattered signal into an electrical signal. A wide bandwidth, low noise and low distortion analog variable gain amplifier (DC-300 MHz) amplifies the electrical signal generated by the photodetector before digitization. The variation of the gain of the amplifier makes it possible to obtain a wide dynamic range, which extends over several orders of magnitude (1/410⁵). A fast analog-to-digital converter (ADC 20 MHz digitization rate, 12-bit resolution sampling) that permits a spatial resolution of 7.5 m follows the amplification stage. A high-speed data interface to computer allows fast readout of the acquired signal. Noise and interference, which can affect the performance of the detection chain, will be also discussed.