volker@12: # This Python script will be executed from within the main lidar_correction_ghk.py volker@12: # Probably it will be better in the future to let the main script rather read a conguration file, volker@12: # which might improve the portability of the code within an executable. volker@12: # Due to problems I had with some two letter variables, most variables are now with at least volker@12: # three letters mixed small and capital. volker@28: # Error calculation? volker@28: # False: only calculate the GHK-parameters. True: calculate also errors. Can take a long time. volker@16: Error_Calc = True volker@16: volker@12: # Header to identify the lidar system volker@17: # volker@28: EID = "xx" # Earlinet station ID volker@12: LID = "example lidar" # Additional lidar ID (short descriptive text) volker@12: print(" Lidar system :", EID, ", ", LID) volker@12: volker@28: # +++ IL Laser beam polarisation and +-Uncertainty volker@23: DOLP, dDOLP, nDOLP = 0.995, 0.005, 1 #degree of linear polarization; default 1 volker@16: RotL, dRotL, nRotL = 0., 2., 1 #alpha; rotation of laser polarization in degrees; default 0 volker@13: volker@13: # +++ ME Emitter optics and +-Uncertainty; default = no emitter optics volker@28: DiE, dDiE, nDiE = 0.0, 0.1, 0 # Diattenuation; default 0 volker@28: TiE = 1.0 # Unpolarized transmittance; default 1 volker@28: RetE, dRetE, nRetE = 0., 180., 0 # Retardance in degrees; default 0 volker@28: RotE, dRotE, nRotE = 0., 1., 0 # beta: Rotation of optical element in degrees; default 0 volker@12: volker@13: # +++ MO Receiver optics including telescope volker@28: DiO, dDiO, nDiO = 0.0, 0.2, 1 # Diattenuation; default 0 volker@28: TiO = 1.0 # Unpolarized transmittance; default 1 volker@28: RetO, dRetO, nRetO = 0., 180., 0 # Retardance in degrees; default 0 volker@28: RotO, dRotO, nRotO = 0., 0.1, 0 #gamma: Rotation of the optical element in degrees; default 0 volker@13: volker@13: # +++++ PBS MT Transmitting path defined with TS, TP, PolFilter extinction ratio ERaT, and +-Uncertainty volker@13: # --- Polarizing beam splitter transmitting path volker@26: TP, dTP, nTP = 0.95, 0.01, 1 # transmittance of the PBS for parallel polarized light volker@28: TS, dTS, nTS = 0.005, 0.001, 1 # transmittance of the PBS for cross polarized light volker@13: RetT, dRetT, nRetT = 0.0, 180., 0 # Retardance in degrees volker@13: # --- Pol.Filter behind transmitted path of PBS volker@28: ERaT, dERaT, nERaT = 0.001, 0.001, 0 # Extinction ratio volker@28: RotaT, dRotaT, nRotaT = 0., 1., 0 # Rotation of the Pol.-filter in degrees; usually close to 0° because TP >> TS, but for PollyXTs it can also be close to 90° volker@13: # -- volker@28: TiT = 0.5 * (TP + TS) # do not change this volker@28: DiT = (TP-TS)/(TP+TS) # do not change this volker@28: DaT = (1-ERaT)/(1+ERaT) # do not change this volker@28: TaT = 0.5*(1+ERaT) # do not change this volker@12: volker@28: # +++++ PBS MR Reflecting path defined with RS, RP, and cleaning PolFilter extinction ratio ERaR and +-Uncertainty volker@13: # ---- for PBS without absorption the change of RS and RP must depend on the change of TP and TS. Hence the values and uncertainties are not independent. volker@28: RS_RP_depend_on_TS_TP = True volker@13: # --- Polarizing beam splitter reflecting path volker@13: if(RS_RP_depend_on_TS_TP): volker@13: RP, dRP, nRP = 1-TP, 0.00, 0 # do not change this volker@13: RS, dRS, nRS = 1-TS, 0.00, 0 # do not change this volker@13: else: volker@26: RP, dRP, nRP = 0.05, 0.01, 1 # change this if RS_RP_depend_on_TS_TP = False; reflectance of the PBS for parallel polarized light volker@26: RS, dRS, nRS = 0.98, 0.01, 1 # change this if RS_RP_depend_on_TS_TP = False; reflectance of the PBS for cross polarized light volker@26: RetR, dRetR, nRetR = 0.0, 180., 0 # Retardance in degrees volker@13: # --- Pol.Filter behind reflected path of PBS volker@16: ERaR, dERaR, nERaR = 0.001, 0.001, 1 # Extinction ratio volker@16: RotaR, dRotaR, nRotaR = 90., 1., 1 # Rotation of the Pol.-filter in degrees; usually 90° because RS >> RP, but for PollyXTs it can also be 0° volker@13: # -- volker@28: TiR = 0.5 * (RP + RS) # do not change this volker@28: DiR = (RP-RS)/(RP+RS) # do not change this volker@28: DaR = (1-ERaR)/(1+ERaR) # do not change this volker@28: TaR = 0.5*(1+ERaR) # do not change this volker@28: # NEW --- Additional ND filter transmission (attenuation) during the calibration volker@28: TCalT, dTCalT, nTCalT = 1, 0.01, 0 # transmitting path, default 1, 0, 0 volker@28: TCalR, dTCalR, nTCalR = 0.1, 0.001, 1 # reflecting path, default 1, 0, 0 volker@12: volker@28: # +++ Orientation of the PBS with respect to the reference plane (see Improvements_of_lidar_correction_ghk_ver.0.9.8_190124.pdf) volker@28: # Y = +1: polarisation in reference plane is finally transmitted, volker@28: # Y = -1: polarisation in reference plane is finally reflected. volker@13: Y = +1. volker@12: volker@28: # +++ Calibrator volker@28: volker@12: # --- Calibrator Type used; defined by matrix values below volker@12: TypeC = 3 #Type of calibrator: 1 = mechanical rotator; 2 = hwp rotator (fixed retardation); 3 = linear polarizer; 4 = qwp; 5 = circular polarizer; 6 = real HWP calibration +-22.5° volker@28: volker@28: # --- Calibrator Location volker@28: LocC = 3 #location of calibrator: 1 = behind laser; 2 = behind emitter; 3 = before receiver; 4 = before PBS volker@13: # --- MC Calibrator parameters volker@12: if TypeC == 1: #mechanical rotator volker@26: DiC, dDiC, nDiC = 0., 0., 0 # Diattenuation volker@12: TiC = 1. volker@26: RetC, dRetC, nRetC = 0., 0., 0 # Retardance in degrees volker@26: RotC, dRotC, nRotC = 0., 0.1, 1 #constant calibrator rotation offset epsilon volker@12: # Rotation error without calibrator: if False, then epsilon = 0 for normal measurements volker@12: RotationErrorEpsilonForNormalMeasurements = True # is in general True for TypeC == 1 calibrator volker@28: elif TypeC == 2: # HWP simulated by rotator without retardance! volker@26: DiC, dDiC, nDiC = 0., 0., 0 # Diattenuation; ideal 0.0 volker@12: TiC = 1. volker@26: RetC, dRetC, nRetC = 180., 0., 0 # Retardance in degrees volker@12: #NOTE: use here twice the HWP-rotation-angle volker@26: RotC, dRotC, nRotC = 0.0, 0.1, 1 #constant calibrator rotation offset epsilon volker@12: RotationErrorEpsilonForNormalMeasurements = True # is in general True for TypeC == 2 calibrator volker@16: elif TypeC == 3: # linear polarizer calibrator. Diattenuation DiC = (1-ERC)/(1+ERC); ERC = extinction ratio of calibrator volker@28: DiC, dDiC, nDiC = 0.9998, 0.00019, 1 # Diattenuation; ideal 1.0 volker@16: TiC = 0.4 # ideal 0.5 volker@28: RetC, dRetC, nRetC = 0., 180., 3 # Retardance in degrees volker@26: RotC, dRotC, nRotC = 0.0, 0.1, 0 #constant calibrator rotation offset epsilon volker@12: RotationErrorEpsilonForNormalMeasurements = False # is in general False for TypeC == 3 calibrator volker@12: elif TypeC == 4: # QWP calibrator volker@26: DiC, dDiC, nDiC = 0.0, 0., 0 # Diattenuation; ideal 0.0 volker@12: TiC = 1.0 # ideal 0.5 volker@26: RetC, dRetC, nRetC = 90., 0., 0 # Retardance in degrees volker@26: RotC, dRotC, nRotC = 0.0, 0.1, 1 #constant calibrator rotation offset epsilon volker@12: RotationErrorEpsilonForNormalMeasurements = False # is False for TypeC == 4 calibrator volker@26: elif TypeC == 6: # real half-wave plate rotator calibration at +-22.5° => rotated_diattenuator_X22x5deg.odt volker@26: DiC, dDiC, nDiC = 0., 0., 0 # Diattenuation; ideal 0.0 volker@12: TiC = 1. volker@26: RetC, dRetC, nRetC = 180., 0., 0 # Retardance in degrees volker@12: #Note: use real HWP angles here volker@26: RotC, dRotC, nRotC = 0.0, 0.1, 1 #constant calibrator rotation offset epsilon volker@12: RotationErrorEpsilonForNormalMeasurements = True # is in general True for TypeC == 6 calibrator volker@12: else: volker@12: print ('calibrator not implemented yet') volker@12: sys.exit() volker@12: volker@16: # --- LDRCal assumed atmospheric linear depolarization ratio during the calibration measurements in calibration range with almost clean air (first guess) volker@28: LDRCal,dLDRCal,nLDRCal= 0.2, 0.15, 1 # spans most of the atmospheric depolarisation variability volker@28: # LDRCal,dLDRCal,nLDRCal= 0.009, 0.005, 1 # spans the interference filter influence volker@21: volker@12: # ==================================================== volker@12: # NOTE: there is no need to change anything below. volker@28: # ==================================================== volker@28: # !!! don't change anything in this section !!! volker@28: # NEW *** volker@28: bPlotEtax = False # plot error histogramms for Etax volker@28: volker@28: # *** Only for signal noise errors *** volker@28: nNCal = 0 # error nNCal, calibration signals: one-sigma in steps to left and right volker@28: nNI = 0 # error nNI, 0° signals: one-sigma in steps to left and right; NI signals are calculated from NCalT and NCalR in main programm, but noise is assumed to be independent. volker@28: volker@28: # --- number of photon counts in the signal summed up in the calibration range during the calibration measurements volker@28: NCalT = 28184 # default 1e6, assumed the same in +45° and -45° signals volker@28: NCalR = 28184 # default 1e6, assumed the same in +45° and -45° signals volker@28: NILfac = 2 # (relative duration (laser shots) of standard (0°) measurement to calibration measurements) * (range of std. meas. smoothing / calibration range); example: 100000#/5000# * 100/1000 = 2 volker@28: # LDRmeas below will be used to calculate IR and IT of 0° signals. volker@28: # calculate signal counts only from parallel 0° signal assuming the same electronic amplification in both channels; overwrites above values volker@28: CalcFrom0deg = True volker@28: NI = 1e5 #number of photon counts in the parallel 0°-signal volker@28: volker@28: if(CalcFrom0deg): volker@28: # either eFactT or eFacR is = 1 => rel. amplification volker@28: eFacT = 1 # rel. amplification of transmitted channel, approximate values are sufficient; def. = 1 volker@28: eFacR = 10 # rel. amplification of reflected channel, approximate values are sufficient; def. = 1 volker@28: NILfac = 2 # (relative duration (laser shots) of standard (0°) measurement to calibration measurements) * (range of std. meas. smoothing / calibration range); example: 100000#/5000# * 100/1000 = 2 volker@28: volker@28: NCalT = NI / NILfac * TCalT * eFacT # photon counts in transmitted signal during calibration volker@28: NCalR = NI / NILfac * TCalR * eFacR # photon counts in reflected signal during calibration volker@28: # LDRmeas below will be used to calculate IR and IT of 0° signals. volker@28: # NEW *** End of signal noise error parameters *** volker@28: volker@12: volker@12: # --- LDRtrue for simulation of measurement => LDRsim volker@12: LDRtrue = 0.4 volker@12: LDRtrue2 = 0.004 volker@12: volker@12: # --- measured LDRm will be corrected with calculated parameters GHK volker@12: LDRmeas = 0.3 volker@12: volker@12: # --- this is just for correct transfer of the variables to the main file volker@23: DOLP0, dDOLP, nDOLP = DOLP, dDOLP, nDOLP volker@12: RotL0, dRotL, nRotL = RotL, dRotL, nRotL volker@12: # Emitter volker@12: DiE0, dDiE, nDiE = DiE, dDiE, nDiE volker@12: RetE0, dRetE, nRetE = RetE, dRetE, nRetE volker@12: RotE0, dRotE, nRotE = RotE, dRotE, nRotE volker@12: # Receiver volker@12: DiO0, dDiO, nDiO = DiO, dDiO, nDiO volker@12: RetO0, dRetO, nRetO = RetO, dRetO, nRetO volker@12: RotO0, dRotO, nRotO = RotO, dRotO, nRotO volker@12: # Calibrator volker@12: DiC0, dDiC, nDiC = DiC, dDiC, nDiC volker@12: RetC0, dRetC, nRetC = RetC, dRetC, nRetC volker@12: RotC0, dRotC, nRotC = RotC, dRotC, nRotC volker@12: # PBS volker@12: TP0, dTP, nTP = TP, dTP, nTP volker@12: TS0, dTS, nTS = TS, dTS, nTS volker@12: RetT0, dRetT, nRetT = RetT, dRetT, nRetT volker@12: volker@12: ERaT0, dERaT, nERaT = ERaT, dERaT, nERaT volker@12: RotaT0,dRotaT,nRotaT= RotaT,dRotaT,nRotaT volker@12: volker@12: RP0, dRP, nRP = RP, dRP, nRP volker@12: RS0, dRS, nRS = RS, dRS, nRS volker@12: RetR0, dRetR, nRetR = RetR, dRetR, nRetR volker@12: volker@12: ERaR0, dERaR, nERaR = ERaR, dERaR, nERaR volker@12: RotaR0,dRotaR,nRotaR= RotaR,dRotaR,nRotaR volker@12: volker@12: LDRCal0,dLDRCal,nLDRCal=LDRCal,dLDRCal,nLDRCal