Analysis and Adjustment of Positioning Error of PSD System for Mobile SOF-FTIR

A PSD-based solar spot position detection system is developed for solar tracking closed-loop control of mobile SOF-FTIR (Solar Occultation Flux method based on Fourier Transform Infrared spectrometer). The positioning error factors of PSD (position sensitive detector) are analyzed in detail. A voltage model for PSD signal conditioning circuit has been established to investigate the noise factors. The model shows that the positioning error is mainly related to PSD dark current and circuit gain. A static voltage deduction calibration method based on genetic algorithm is proposed to eliminate the effect of dark current. The gain ratio between channels is calculated based on the fitting curve slope of discrete position data of PSD center point with different light intensity for circuit gain calibration. The positioning accuracy and precision are greatly enhanced, especially when the light intensity is weak, compared with uncalibrated results. The positioning accuracy of center, middle and edge areas of PSD can reach 0.14%, 0.49%, and 1.09%, respectively, after correction in the range of light intensity voltage from 40 mV to 20 V. The corresponding standard deviations of each region are 0.005, 0.009, and 0.014, respectively. The adjustment methods proposed in this paper improve both measurement accuracy and detection limit. The results demonstrate that the calibrated PSD positioning accuracy can meet the requirements of SOF-FTIR for solar tracking.

[1]  Jerald Graeme,et al.  Photodiode Amplifiers: OP AMP Solutions , 1995 .

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

[3]  James T. Randerson,et al.  Differences between surface and column atmospheric CO2 and implications for carbon cycle research , 2004 .

[4]  Silvano Donati,et al.  Electro-Optical Instrumentation: Sensing and Measuring with Lasers , 2004 .

[5]  Mohanad Alata,et al.  Developing a multipurpose sun tracking system using fuzzy control , 2005 .

[6]  Anand Asundi,et al.  Measurement accuracy of lateral-effect position-sensitive devices in presence of stray illumination noise , 2008 .

[7]  T. Williams,et al.  Machine vision as a method for characterizing solar tracker performance , 2008, 2008 33rd IEEE Photovoltaic Specialists Conference.

[8]  Yin-guo Huang,et al.  Research on Signal Processing for LD-PSD System Based on Square-Wave Modulation , 2009, 2009 2nd International Congress on Image and Signal Processing.

[9]  Wang Xuanze,et al.  Research on Position Detection of PSD Based on Light Intensity Modulation and Digital Fit , 2009, 2009 WRI Global Congress on Intelligent Systems.

[10]  T. Blumenstock,et al.  Camtracker: a new camera controlled high precision solar tracker system for FTIR-spectrometers , 2010 .

[11]  Jingjing Jin,et al.  A solar ray automatic tracking device based on image sensor , 2011, Proceedings of the 30th Chinese Control Conference.

[12]  Guillaume J. Laurent,et al.  High Dynamics and Precision Optical Measurement Using a Position Sensitive Detector (PSD) in Reflection-Mode: Application to 2D Object Tracking over a Smart Surface , 2012, Sensors.

[13]  Maryam Raoof,et al.  The effect of different needle-insertion depths on the accuracy of the Root ZX II and Root ZX mini apex locators in the presence of various irrigants , 2013 .

[14]  Yantao Shen,et al.  Enhancing measurement accuracy of position sensitive detector (PSD) systems using the Kalman filter and distortion rectifying , 2013, 2013 IEEE SENSORS.

[15]  James W. Hannigan,et al.  Development of a digital mobile solar tracker , 2015 .

[16]  A Faught,et al.  WE-DE-201-07: Measurement of Real-Time Dose for Tandem and Ovoid Brachytherapy Procedures Using a High Precision Optical Fiber Radiation Detector. , 2016, Medical physics.

[17]  José Luis Lázaro,et al.  Analysis and Calibration of Sources of Electronic Error in PSD Sensor Response , 2016, Sensors.