Lidar polarisation GHK-parameter and error calculation: system_settings/optic_input_0.9.8h-PollyXT_Cyprus_532_210429_vf

system_settings/optic_input_0.9.8h-PollyXT_Cyprus_532_210429_vf_4.py@6eb017aeb6fe (annotated)

system_settings/optic_input_0.9.8h-PollyXT_Cyprus_532_210429_vf_4.py

Wed, 07 Jul 2021 16:00:34 +0200

author: Volker Freudenthaler
date: Wed, 07 Jul 2021 16:00:34 +0200
changeset 52: 6eb017aeb6fe
parent 51: 10fb0fc3d79f
permissions: -rw-r--r--

Merge

 # This Python script will be executed from within the main lidar_correction_ghk.py
 # Probably it will be better in the future to let the main script rather read a conguration file,
 # which might improve the portability of the code within an executable.
 # Due to problems I had with some two letter variables, most variables are now with at least
 # three letters mixed small and capital.
 # To be used with lidar_correction_ghk.py ver. 0.9.5 and larger
 # Do you want to calculate the errors? If not, just the GHK-parameters are determined.
 Error_Calc = True
 # Header to identify the lidar system
 EID = "li"				# Earlinet station ID
 LID = "PollyXT Cyprus 210429 532 approx 4" 	# Additional lidar ID (short descriptive text)
 print("    Lidar system :", EID, ", ", LID)
 # +++ IL Laser and +-Uncertainty
 Qin, dQin, nQin = 0.9672, 0.01,  1	# second Stokes vector parameter; default 1 => linear polarization  0.999 => LDR = 0.0005
 Vin, dVin, nVin = 0.0, 0.0,  0	# fourth Stokes vector parameter; default 0  => corresponds to LDR 0.0005 with DOP 1
 RotL, dRotL, nRotL = 91.65,  0.24,  1	 #alpha; rotation of laser polarization in degrees; alle wellenlängen im PollyXT Lacros sind vertical zum opt. Tisch polarisiert.
 # +++ ME Emitter optics and +-Uncertainty;  default = no emitter optics
 DiE, dDiE, nDiE 	= 0.0, 	0.02, 	0	# Diattenuation
 TiE 		        = 1.0		        # Unpolarized transmittance
 RetE, dRetE, nRetE 	= 0., 	180., 	0	# Retardance in degrees
 RotE, dRotE, nRotE 	= 0., 	1.0, 	0	# beta: Rotation of the optical element in degrees
 # +++ MO Receiver optics including telescope
 DiO,  dDiO, nDiO 	 = 0.0, 0.02,    0	# Diattenuation
 TiO 				= 1.0 				# Unpolarized transmittance
 RetO, dRetO, nRetO 	= 0., 	180., 	0	# Retardance in degrees
 RotO, dRotO, nRotO 	= 0., 	0.5, 	0	# gamma: Rotation of the optical element in degrees
 # +++++ PBS MT Transmitting path defined with TS, TP, PolFilter extinction ratio ERaT, and +-Uncertainty
 #   --- Polarizing beam splitter transmitting path
 TP,   dTP, nTP	 	= 0.5,	0.01,   1 # transmittance of the PBS for parallel polarized light
 TS,   dTS, nTS	 	= 0.5,  0.01,   1 # transmittance of the PBS for cross polarized light
 RetT, dRetT, nRetT	= 0.0,	180.,   0 # Retardance in degrees
 #   --- Pol.Filter behind transmitted path of PBS
 ERaT, dERaT, nERaT	 = 1.0 , 0 , 0 # Extinction ratio 0.00075 +/- 0.00025
 RotaT, dRotaT, nRotaT = 0.,   1.,    1 # Rotation of the Pol.-filter in degrees; usually close to 0° because TP >> TS, but for PollyXTs it can also be close to 90°
 #   --
 TiT = 0.5 * (TP + TS)
 DiT = (TP-TS)/(TP+TS)
 DaT = (1-ERaT)/(1+ERaT)
 TaT = 0.5*(1+ERaT)
 # +++++ PBS MR Reflecting path defined with RS, RP, PolFilter extinction ratio ERaR  and +-Uncertainty
 #   ---- 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.
 RS_RP_depend_on_TS_TP = False
 #   --- Polarizing beam splitter reflecting path
 #if(RS_RP_depend_on_TS_TP):
 #    RP, dRP, nRP        = 1-TP,  0.00, 0    # do not change this
 #    RS, dRS, nRS        = 1-TS,  0.00, 0    # do not change this
 #else:
 RP, dRP, nRP        = 0.002,  0.001, 1    # change this if RS_RP_depend_on_TS_TP = False; reflectance of the PBS for parallel polarized light
 RS, dRS, nRS        = 0.998,  0.001, 1    # change this if RS_RP_depend_on_TS_TP = False; reflectance of the PBS for cross polarized light
 RetR, dRetR, nRetR	    = 0.0,  180., 0    # Retardance in degrees
 #   --- Pol.Filter behind reflected path of PBS
 ERaR, dERaR, nERaR	    = 1.0,  0.0,  0 # Extinction ratio
 RotaR, dRotaR, nRotaR   = 0.,   1.,   0  # Rotation of the Pol.-filter in degrees; usually close to 90° because RS >> RP, but for PollyXTs it can also be close to 0°
 #   --
 TiR = 0.5* (RP + RS)
 DiR = (RP-RS)/(RP+RS)
 DaR = (1-ERaR)/(1+ERaR)
 TaR = 0.5*(1+ERaR)
 # NEW --- Additional ND filter transmission (attenuation) during the calibration
 TCalT, dTCalT, nTCalT  = 1, 0.01, 0		# transmitting path, default 1, 0, 0
 TCalR, dTCalR, nTCalR = 1, 0.0001, 0		# reflecting path, default 1, 0, 0
 # +++ Orientation of the PBS with respect to the reference plane (see Improvements_of_lidar_correction_ghk_ver.0.9.8_190124.pdf)
 #    Y = +1: polarisation in reference plane is finally transmitted,
 #    Y = -1: polarisation in reference plane is finally reflected.
 Y = -1.
 # +++ Calibrator Location
 # --- Calibrator Type used; defined by matrix values below
 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°
 # --- Calibrator Location
 LocC = 3 #location of calibrator: 1 = behind laser; 2 = behind emitter; 3 = before receiver; 4 = before PBS
 # --- MC Calibrator parameters
 if TypeC == 1:  #mechanical rotator
 	DiC, dDiC, nDiC 	= 0., 	0., 	0	# Diattenuation
 	TiC = 1.
 	RetC, dRetC, nRetC 	= 0., 	0., 	0	# Retardance in degrees
 	RotC, dRotC, nRotC 	= 0., 	1.0, 	1	#constant calibrator rotation offset epsilon
 	# Rotation error without calibrator: if False, then epsilon = 0 for normal measurements
 	RotationErrorEpsilonForNormalMeasurements = True	# 	is in general True for TypeC == 1 calibrator
 elif TypeC == 2:   # HWP rotator without retardance!
 	DiC, dDiC, nDiC 	= 0., 	0., 	0	# Diattenuation; ideal 0.0
 	TiC = 1.
 	RetC, dRetC, nRetC 	= 180., 0., 	0	# Retardance in degrees
 	#NOTE: use here twice the HWP-rotation-angle
 	RotC, dRotC, nRotC 	= 0.0, 	0.1, 	1	#constant calibrator rotation offset epsilon
 	RotationErrorEpsilonForNormalMeasurements = True	# 	is in general True for TypeC == 2 calibrator
 elif TypeC == 3:   # linear polarizer calibrator. Diattenuation DiC = (1-ERC)/(1+ERC); ERC = extinction ratio of calibrator
 	DiC, dDiC, nDiC 	= 0.99928, 0.00021, 1	# Diattenuation; ideal 1.0
 	TiC = 0.4	# ideal 0.5
 	RetC, dRetC, nRetC 	= 0., 	0., 	0	# Retardance in degrees
 	RotC, dRotC, nRotC 	= 0.0, 	0.1, 	0	#constant calibrator rotation offset epsilon
 	RotationErrorEpsilonForNormalMeasurements = False	# 	is in general False for TypeC == 3 calibrator
 elif TypeC == 4:   # QWP calibrator
 	DiC, dDiC, nDiC 	= 0.0, 	0., 	0	# Diattenuation; ideal 0.0
 	TiC = 1.0	# ideal 0.5
 	RetC, dRetC, nRetC 	= 90., 	0., 	0	# Retardance in degrees
 	RotC, dRotC, nRotC 	= 0.0, 	0.1, 	1	#constant calibrator rotation offset epsilon
 	RotationErrorEpsilonForNormalMeasurements = False	# 	is  False for TypeC == 4 calibrator
 elif TypeC == 6:   # real half-wave plate rotator calibration at +-22.5°  => rotated_diattenuator_X22x5deg.odt
 	DiC, dDiC, nDiC 	= 0., 	0., 	0	# Diattenuation; ideal 0.0
 	TiC = 1.
 	RetC, dRetC, nRetC 	= 180., 0., 	0	# Retardance in degrees
     #Note: use real HWP angles here
 	RotC, dRotC, nRotC 	= 0.0, 	0.1, 	1	#constant calibrator rotation offset epsilon
 	RotationErrorEpsilonForNormalMeasurements = True	# 	is in general True for TypeC == 6 calibrator
 else:
     print ('calibrator not implemented yet')
     sys.exit()
 # --- LDRCal uncertainty: atmospheric linear depolarization ratio in the range used for the polarisation calibration during the calibration measurements
 LDRCal,dLDRCal,nLDRCal= 0.11, 0.1, 1     # spans the atmopsheric variability
 # --- example: LDRCal uncertainty with almost clean air
 # LDRCal,dLDRCal,nLDRCal= 0.009, 0.005, 1     # spans the interference filter influence between Cabannes and Rayleigh scattering
 # ====================================================
 # NOTE: there is no need to change anything below.
 # ====================================================
 # !!! don't change anything in this section !!!
 bPlotEtax = False    # plot error histogramms for Etax
 # NEW *** Only for signal noise errors ***
 nNCal = 0           # error nNCal, calibration signals: one-sigma (fixed) in nNCal steps to left and right
 nNI   = 0           # error nNI, 0° signals: one-sigma (fixed) in nNI steps to left and right; NI signals are calculated from NCalT and NCalR in main programm, but noise is assumed to be independent.
 #   --- number of photon counts in the signal summed up in the calibration range during the calibration measurements
 NCalT = 40000		# default 1e6, assumed the same in +45° and -45° signals; counts with ND-filter TCalT
 NCalR = 40000		# default 1e6, assumed the same in +45° and -45° signals; counts with ND-filter TCalR
 NILfac = 1          # (relative duration (laser shots) of standard (0°) measurement to calibration measurements) * (range of std. meas. smoothing / calibration range); example: 100000#/5000# * 100/1000 = 2
                     #  LDRmeas below will be used to calculate IR and IT of 0° signals.
 # calculate signal counts only from parallel 0° signal assuming the same electronic amplification in both channels; overwrites above values
 CalcFrom0deg = True
 NI = 100000000 #number of photon counts in the parallel 0°-signal 40000
 if(CalcFrom0deg):
     # either eFactT or eFacR is = 1 => rel. amplification
 	eFacT = 1                     			# rel. amplification of transmitted channel, approximate values are sufficient; def. = 1
 	eFacR = 1                    			# rel. amplification of reflected channel, approximate values are sufficient; def. = 1
 	NILfac = 1           					# (relative duration (laser shots) of standard (0°) measurement to calibration measurements) * (range of std. meas. smoothing / calibration range); example: 100000#/5000# * 100/1000 = 2
 	NCalT = NI / NILfac * TCalT * eFacT		# photon counts in transmitted signal during calibration
 	NCalR = NI / NILfac * TCalR * eFacR	    # photon counts in reflected signal during calibration
                         #  LDRmeas below will be used to calculate IR and IT of 0° signals.
 # NEW *** End of signal noise error parameters ***
 # --- LDRtrue for simulation of measurement => LDRsim
 LDRtrue = 0.004
 LDRtrue2 = 0.004
 # --- measured LDRm will be corrected with calculated parameters GHK
 LDRmeas = 0.3
 # --- this is just for correct transfer of the variables to the main file
 Qin0, dQin, nQin = Qin, dQin, nQin
 Vin0, dVin, nVin = Vin, dVin, nVin
 RotL0, dRotL, nRotL = RotL, dRotL, nRotL
 # Emitter
 DiE0,  dDiE,  nDiE  = DiE,  dDiE, 	nDiE
 RetE0, dRetE, nRetE = RetE, dRetE, nRetE
 RotE0, dRotE, nRotE = RotE, dRotE, nRotE
 # Receiver
 DiO0,  dDiO,  nDiO  = DiO,  dDiO, 	nDiO
 RetO0, dRetO, nRetO = RetO, dRetO, nRetO
 RotO0, dRotO, nRotO = RotO, dRotO, nRotO
 # Calibrator
 DiC0,  dDiC,  nDiC  = DiC,  dDiC, 	nDiC
 RetC0, dRetC, nRetC = RetC, dRetC, nRetC
 RotC0, dRotC, nRotC = RotC, dRotC, nRotC
 # PBS
 TP0,   dTP,   nTP   = TP,   dTP, 	nTP
 TS0,   dTS,   nTS   = TS,   dTS, 	nTS
 RetT0, dRetT, nRetT	= RetT, dRetT, nRetT
 ERaT0, dERaT, nERaT	= ERaT, dERaT, nERaT
 RotaT0,dRotaT,nRotaT= RotaT,dRotaT,nRotaT
 RP0,   dRP,   nRP   = RP,   dRP,   nRP
 RS0,   dRS,   nRS   = RS,   dRS,   nRS
 RetR0, dRetR, nRetR	= RetR, dRetR, nRetR
 ERaR0, dERaR, nERaR	= ERaR, dERaR, nERaR
 RotaR0,dRotaR,nRotaR= RotaR,dRotaR,nRotaR
 LDRCal0,dLDRCal,nLDRCal=LDRCal,dLDRCal,nLDRCal

Mercurial > public > atmospheric_lidar_ghk / annotate

system_settings/optic_input_0.9.8h-PollyXT_Cyprus_532_210429_vf_4.py@6eb017aeb6fe (annotated)

system_settings/optic_input_0.9.8h-PollyXT_Cyprus_532_210429_vf_4.py