Unified Pulsed Laser Range Finder and Velocimeter using Ultra-Fast Time-To-Digital Converter

In this paper, we present a high accuracy laser range finder and velocimeter using ultra-fast time-to-digital converter (TDC). The system operation is based on the measuring the round-trip time of a narrow laser pulse. A low-dark current high-speed PIN photodiode is used to detect the triggered laser beam and to produce start signal. The pulsed laser diode generates 45W optical power at 30ns duration time and 905nm wavelength. A high-responsivity avalanche photodiode (APD) detects the reflected beam from the target. An optical head including beam splitter, lenses and optical filters is also designed and implemented. The signal conditioner of the system includes pre- and post-amplifiers, comparator, opto-isolators and monostable. By using a 3MV/W reach-through structure avalanche photodiode and a wideband pre-amplifier, the pre-amplifier output reaches 15.9mV, resulting from the minimum detectable optical power. The APD temperature and as a result its responsivity is controlled by a thermoelectric controller unit. The start and stop signals from PIN and APD are led to the time-to-digital converter to count the round- trip time of the laser beam. The system is tested by a retro-reflector as a target for 30- 1200m distances. The resolutions of the distance and velocity measurement are limited to 18.75mm and 1.2m/s, respectively. In the worst condition, the minimum reflected optical power is limited to about 5.3nW in 1.2km distance.

[1]  Pei-wen Que,et al.  Maximum non-Gaussianity parameters estimation of ultrasonic echoes and its application in ultrasonic non-destructive evaluation , 2007 .

[2]  Anssi Mäkynen,et al.  Position-sensitive devices and sensor systems for optical tracking and displacement sensing applications , 2000 .

[3]  T. Refaat,et al.  Characterization of Advanced Avalanche Photodiodes for Water Vapor Lidar Receivers , 2000 .

[4]  G. Buller,et al.  Laser-based distance measurement using picosecond resolution time-correlated single-photon counting , 2000 .

[5]  Nihal Fatma Güler,et al.  The electronic detail of a pulsed doppler blood flow measurement system , 1990 .

[6]  A robust photo-interferometric technique to obtain the refractive index and thickness of non-absorbing stand-alone films , 2000 .

[7]  Martial Geiser,et al.  Laser Doppler instrument to investigate retinal neural activity-induced changes in optic nerve head blood flow , 2005 .

[8]  Jürgen Czarske.  A miniaturized dual-fibre laser Doppler sensor , 2001 .

[9]  Robert H. Redus,et al.  Gain and noise in very high-gain avalanche photodiodes: theory and experiment , 1996, Optics & Photonics.

[10]  S. H. Mohammadnezhad,et al.  ALTITUDE MEASUREMENT USING LASER BEAM REFLECTED FROM WATER SURFACE , 2005 .

[11]  Mohammadnejad Shahram,et al.  Design and Simulation of a High Resolution FMCW-Like Laser Range-Finder , 2005 .

[12]  F. Tamer,et al.  Temperature Control of Avalanche Photodiode Using Thermoelectric Cooler , 1999 .

[13]  Saeed Olyaee,et al.  Low-Noise High-Accuracy TOF Laser Range Finder , 2008 .

[14]  Saeed Olyaee,et al.  A NEW HIGH ACCURACY TIME-OF-FLIGHT RANGE FINDER WITH Q-SWITCHING ND:YAG LASER , 2004 .

[15]  Alan Murray,et al.  Microvascular blood flow and skin temperature changes in the fingers following a deep nspiratory gasp. , 2002, Physiological measurement.

[16]  Bahaa E. A. Saleh,et al.  Generalized excess noise factor for avalanche photodiodes of arbitrary structure , 1990 .

[17]  Tamer F. Refaat,et al.  Comparison between super low ionization ratio and reach through avalanche photodiode structures , 2000 .

[18]  F Refaat Tamer,et al.  Advanced Atmospheric Water Vapor DIAL Detection System , 2000 .

[19]  S. Mohammad Nejad,et al.  Cross-talk and intermediate frequency deviation effects on phase-shift range finder , 2002 .

[20]  J. N. Hollenhorst.  A theory of multiplication noise , 1990 .

[21]  Michitsugu Mori,et al.  Ultrasonic pulse-Doppler flow meter application for hydraulic power plants , 2008 .

[22]  F. Esen,et al.  Detrended fluctuation analysis of laser Doppler flowmetry time series: the effect of extrinsic and intrinsic factors on the fractal scaling of microvascular blood flow , 2006, Physiological measurement.

[23]  K. Määtta,et al.  Profiling of hot surfaces by pulsed time-of-flight laser range finder techniques. , 1993, Applied optics.

[24]  Anton Schleiss,et al.  Improvement of Acoustic Doppler Velocimetry in steady and unsteady turbulent open-channel flows by means of seeding with hydrogen bubbles , 2008 .