ames research center airborne sensor facility hemisphere calibration effects on calibration –stray...
TRANSCRIPT
Ames Research CenterAmes Research Center Airborne Sensor FacilityAirborne Sensor Facility
Hemisphere Calibration
• Effects on calibration– Stray Light – Shield Starting with Crystal– Stable Supply and Selected bulbs - Crystal– Warm-up Time – Operational issue– Humidity – Improvement possible– Temperature– Optics Degradation
• Deployment Results– Crystal, Texas 2002, Thorpex
Ames Research CenterAmes Research Center Airborne Sensor FacilityAirborne Sensor Facility
-1.0%
-0.5%
0.0%
0.5%
1.0%
0 50 100 150 200 250
Minutes x 2
Perc
en
t ch
an
ge
Diode
Hemisphere Monitor Diode vs Run Time
• Varying warm-up time changes output by over 1%• Preflight data taken with 15 to 45 minutes of
warm-up• Loud alarm needs to signal when to take data
Ames Research CenterAmes Research Center Airborne Sensor FacilityAirborne Sensor Facility
Preflight Humidity sensitivity• Port 2 fogs often• N2 Purge needed• Fore optics occasionally
mist over slightly
Thorpex MAS Humidity Effects
-80%
-70%
-60%
-50%
-40%
-30%
-20%
-10%
0%
10%
0 5 10 15 20 25
channel #P
erce
nt C
hang
e
614 - 16.9C
615 - 17.3C
616 - 17.3C
617 - 16.3C
618 - 16.7C
619 - 16.6C
931 - 19.4C
932 - 20.5C
934 - 19.5C
935 - 18.9C
Texas 2002 MAS Preflight Change
-50%
-40%
-30%
-20%
-10%
0%
10%
0 5 10 15 20 25
Channel #
Pe
rce
nt
Ch
an
ge
fro
m S
tart 913
914
916
917
918
919
920
921
922
923
30" sphere
Ames Research CenterAmes Research Center Airborne Sensor FacilityAirborne Sensor Facility
Hemisphere Temperature Stability, Crystal, Texas 2002, Thorpex
Hemisphere Temperature StabilityData from Crystal, Texas 2002, Thorpex
Current changes 20ppm / C
-1.0%
-0.5%
0.0%
0.5%
1.0%
10 15 20 25 30 35
Degrees C
Per
cen
t ch
ang
e
Monitor Diode
Lamp Amps
Lamp Volts
These data points were taken at exactly 25 minutes after Hemisphere start
Ames Research CenterAmes Research Center Airborne Sensor FacilityAirborne Sensor Facility
CRYSTAL-Face: Daily Hemisphere Response & Projected Degradation Used in L-1B Calibration (based on 30” sphere)CRYSTAL-Face: Daily Hemisphere Response & Projected Degradation Used in L-1B Calibration (based on 30” sphere)
Ames Research CenterAmes Research Center Airborne Sensor FacilityAirborne Sensor Facility
THORPEX: Daily Hemisphere Response & Projected Degradation Used in L-1B Calibration (based on 30” sphere)THORPEX: Daily Hemisphere Response & Projected Degradation Used in L-1B Calibration (based on 30” sphere)
Ames Research CenterAmes Research Center Airborne Sensor FacilityAirborne Sensor Facility
Crystal Sphere vs Hemisphere & Humidity
Crystal Sphere vs Hemisphere Slopes & Humidity
-5%
-4%
-3%
-2%
-1%
0%
1%
2%
3%
4%
5%
948 949 950 951 952 953 954 955 956 957
flight #
De
lta
sp
he
re -
de
lta
he
mis
ph
ere
30
40
50
60
70
80
90
ch1
ch2
ch3
ch4
ch5
ch6
ch7
ch8
ch9
ch10
ch11
ch12
ch13
ch14
ch15
ch16
ch17
ch18
ch19
ch20
ch21
ch22
ch23
ch24
ch25
humidity
Ames Research CenterAmes Research Center Airborne Sensor FacilityAirborne Sensor Facility
Texas 2002 Port 1 Preflight Change
Thorpex Port 1 Preflight Change
-8%
-6%
-4%
-2%
0%
2%
4%
6%
1 3 5 7 9
channel #
Pe
rce
nt
Ch
an
ge
fro
m
Sta
rt
614 - 16.9C
615 - 17.3C
616 - 17.3C
617 - 16.3C
618 - 16.7C
619 - 16.6C
931 - 19.4C
932 - 20.5C
934 - 19.5C
935 - 18.9C
30 inch
Ames Research CenterAmes Research Center Airborne Sensor FacilityAirborne Sensor Facility
• Used by Keck Telescope
• Started in Hawaii ’03• Eliminated
degradation• Cleaned after
every flight
CO2 Snow Cleaning