Mercurial > public > atmospheric_lidar_ghk / file revision

# 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 = "xx"				# Earlinet station ID
LID = "example lidar" 	# Additional lidar ID (short descriptive text)
print("    Lidar system :", EID, ", ", LID)

# +++ IL Laser 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
TiE 		        = 1.0		                # Unpolarized transmittance
RetE, dRetE, nRetE 	= 0., 	180., 	0	# Retardance in degrees
RotE, dRotE, nRotE 	= 0., 	1.0, 	0	# beta: Rotation of optical element in degrees

# +++ MO Receiver optics including telescope 
DiO,  dDiO, nDiO 	= 0.0, 	0.1,    1	# 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	 	= 0.95,	0.01,   1 # transmittance of the PBS for parallel polarized light
TS,   dTS, nTS	 	= 0.02,	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	 = 0.001, 0.001, 1 # Extinction ratio
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        = 0.05,  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)
DiR = (RP-RS)/(RP+RS)
DaR = (1-ERaR)/(1+ERaR)
TaR = 0.5*(1+ERaR)

# +++ Orientation of the PBS with respect to the reference plane (see Polarisation-orientation.png and Polarisation-orientation-2.png in /system_settings)
#    Y = +1: polarisation in reference plane is transmitted, 
#    Y = -1: polarisation in reference plane is reflected. 
Y = +1.

# +++ Calibrator Location
LocC = 3 #location of calibrator: 1 = behind laser; 2 = behind emitter; 3 = before receiver; 4 = before PBS
# --- 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°
# --- 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 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, 0.0001, 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 assumed atmospheric linear depolarization ratio during the calibration measurements in calibration range with almost clean air (first guess)
LDRCal,dLDRCal,nLDRCal= 0.009, 0.005, 1     # spans the interference filter influence 
 
# ====================================================
# NOTE: there is no need to change anything below.

# --- 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