Lidar polarisation GHK-parameter and error calculation: system_settings/optic_input_example

system_settings/optic_input_example_lidar.py@5ff1100017b6 (annotated)

system_settings/optic_input_example_lidar.py

Fri, 29 May 2020 20:56:12 +0200

author: Volker Freudenthaler
date: Fri, 29 May 2020 20:56:12 +0200
changeset 39: 5ff1100017b6
parent 28: 79fa4a41420f
permissions: -rw-r--r--

added: Improvements_of_lidar_correction_ghk_200529.pdf
Including the description of changes for the script version 0.9.8e4.

 # 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.
 # Error calculation?
 # False: only calculate the GHK-parameters. True: calculate also errors. Can take a long time.
 Error_Calc = True
 # Header to identify the lidar system
 #
 EID = "xx"				# Earlinet station ID
 LID = "example lidar" 	# Additional lidar ID (short descriptive text)
 print("    Lidar system :", EID, ", ", LID)
 # +++ IL Laser beam polarisation and +-Uncertainty
 DOLP, dDOLP, nDOLP = 0.995, 0.005,  1	#degree of linear polarization; default 1
 RotL, dRotL, nRotL 	= 0., 	2., 	1	#alpha; rotation of laser polarization in degrees; default 0
 # +++ ME Emitter optics and +-Uncertainty;  default = no emitter optics
 DiE, dDiE, nDiE 	= 0.0, 	0.1, 	0	#  Diattenuation; default 0
 TiE 		        = 1.0		        # Unpolarized transmittance; default 1
 RetE, dRetE, nRetE 	= 0., 	180., 	0	# Retardance in degrees; default 0
 RotE, dRotE, nRotE 	= 0., 	1., 	0	# beta: Rotation of optical element in degrees; default 0
 # +++ MO Receiver optics including telescope
 DiO,  dDiO, nDiO 	= 0.0, 	0.2,    1	# Diattenuation; default 0
 TiO 				= 1.0   	# Unpolarized transmittance; default 1
 RetO, dRetO, nRetO 	= 0., 	180., 	0	# Retardance in degrees; default 0
 RotO, dRotO, nRotO 	= 0., 	0.1, 	0	#gamma: Rotation of the optical element in degrees; default 0
 # +++++ PBS MT Transmitting path defined with TS, TP, PolFilter extinction ratio ERaT, and +-Uncertainty
 #   --- Polarizing beam splitter transmitting path
 TP,   dTP, nTP	 	= 0.95,	0.01,   1 # transmittance of the PBS for parallel polarized light
 TS,   dTS, nTS	 	= 0.005,	0.001,   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	 = 0.001, 0.001, 0 # Extinction ratio
 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°
 #   --
 TiT = 0.5 * (TP + TS)    # do not change this
 DiT = (TP-TS)/(TP+TS)    # do not change this
 DaT = (1-ERaT)/(1+ERaT)    # do not change this
 TaT = 0.5*(1+ERaT)    # do not change this
 # +++++ PBS MR Reflecting path defined with RS, RP, and cleaning 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 = True
 #   --- 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        = 0.05,  0.01, 1    # change this if RS_RP_depend_on_TS_TP = False; reflectance of the PBS for parallel polarized light
     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
 RetR, dRetR, nRetR	    = 0.0,   180., 0    # Retardance in degrees
 #   --- Pol.Filter behind reflected path of PBS
 ERaR, dERaR, nERaR	  = 0.001, 0.001, 1 # Extinction ratio
 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°
 #   --
 TiR = 0.5 * (RP + RS)    # do not change this
 DiR = (RP-RS)/(RP+RS)    # do not change this
 DaR = (1-ERaR)/(1+ERaR)    # do not change this
 TaR = 0.5*(1+ERaR)    # do not change this
 # 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 = 0.1, 0.001, 1		# 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
 # --- 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., 	0.1, 	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 simulated by 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 	= 0.9998, 0.00019, 1	# Diattenuation; ideal 1.0
 	TiC = 0.4	# ideal 0.5
 	RetC, dRetC, nRetC 	= 0., 	180., 	3	# 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 assumed atmospheric linear depolarization ratio during the calibration measurements in calibration range with almost clean air (first guess)
 LDRCal,dLDRCal,nLDRCal= 0.2, 0.15, 1     # spans most of the atmospheric depolarisation variability
 # LDRCal,dLDRCal,nLDRCal= 0.009, 0.005, 1     # spans the interference filter influence
 # ====================================================
 # NOTE: there is no need to change anything below.
 # ====================================================
 # !!! don't change anything in this section !!!
 # NEW ***
 bPlotEtax = False    # plot error histogramms for Etax
 # *** Only for signal noise errors ***
 nNCal = 0           # error nNCal, calibration signals: one-sigma in steps to left and right
 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.
 #   --- number of photon counts in the signal summed up in the calibration range during the calibration measurements
 NCalT = 28184		# default 1e6, assumed the same in +45° and -45° signals
 NCalR = 28184		# default 1e6, assumed the same in +45° and -45° signals
 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
                     #  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 = 1e5 #number of photon counts in the parallel 0°-signal
 if(CalcFrom0deg):
     # either eFactT or eFacR is = 1 => rel. amplification
 	eFacT = 1                     			# rel. amplification of transmitted channel, approximate values are sufficient; def. = 1
 	eFacR = 10                    			# rel. amplification of reflected channel, approximate values are sufficient; def. = 1
 	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
 	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 = 0.4
 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
 DOLP0, dDOLP, nDOLP = DOLP, dDOLP, nDOLP
 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_example_lidar.py@5ff1100017b6 (annotated)

system_settings/optic_input_example_lidar.py