This page provides information on service issues related to ISAR s/n 04. This instrument was fabricated at the National Ocean Center, Southampton and delivered to University of Miami, RSMAS, in September 2005.
SERIAL NUMBERS
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The photograph shows the ISAR and its mounting frame attached to the outside of the M-AERI chassis. The ISAR viewing angle was 45 degrees from nadir (configuration file: I04V0245.txt). The system worked without fail throughout the cruise. The ISAR output strings were read by the SCS (Scientific Computer System) and were collected with computer time stamps. The PC was located inside the M-AERI chassis and each day chassis was opened the SCS data files were copied to a portable memory for processing. |
| The raw (5-sec) data records defined by ISAR5 were processed with a PERL program that averages all temperatures and radiometer readings over (in this case) 30 minutes averaging period. The M-AERI MTL files were read with a MATLAB program that bin-averaged all M-AERI SSST records (about 10-min sample period) into contemporary 30-min averaging periods for comparison with ISAR. There were several rain periods and the ship was in port for about 36 hours. Ocassionally, a computer communication problem caused M-AERI to fail and a reboot was required to get it to function again. All data from these time periods-port time, reboot, rain-were removed from the comparisons. For the good data, the mean difference (ISAR-MAERI) was 0.025 degC and the standard deviation of the difference was 0.36 degC. The standard deviation was somewhat large. Examination of the time series plots for the two instruments indicates that the M-AERI exhibited a high variability while ISAR was fairly steady. |
| The route of the Explorer of the Seas was directly through the Gulf Stream as shown by the AVHRR SST map here. We show here a few spot times during the cruise. The date and hour are shown with the SSST from ISAR. |
ISAR-04 was left operating on the ship and plans are to remove it in mid August.
M-AERI AC --> SONEIL --> 12V BATTERY --> ISAR
This will be small enough to fit in the M-AERI chassis. The M-AERI AC will continue to power the laptop as before.
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The belt slipped and bunched up which jammed the shutter gear mechanism. The end stops (blue) in the new system are very hard and these made it difficult to manually rotate the shutter past the stops. The belt was glued into the groove, but the glue seems to have failed. The belt was easily pulled from the groove and there was a black powder remaining. During this time the belt was re-glued and the system checked in good working order. |
The ISAR-04 was shipped to RSMAS and placed in front of the bath. This calibration was unique because it uses the real-time data collection program called "G".
The Configuration File is read by ISAR during its startup.
The Setup File is used by the averaging program during the real time operation.
The figure to the left shows the results from the real-time processing. The bath was allowed to settle to the target temperature. During the time of the calibration points, bath changes are of the order 0.001. By altering the calibration parameters, Acorr and CalOffset, an optimum fit to the calibration bath data is achieved.
Acorr = 1.008, Offset = 0.08 C.
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The IBM T30 laptop was installed in the SBD case. The expect program G version 07 was installed. Everything was working well except that the ORG voltage never dropped below the threshold. The ISAR configuration file had a rain threshold of 60 mV. The ORG was always above this level. We were running out of time and the mist increased. Therefore we took a chance that all was well and as soon as the rain stopped the ISAR shutter would open. We disembarked at about 4pm, just before the ship sailed.
As it turns out, the ORG output never dropped below the 60 mV threshold. Therefore, on this entire cruise the iridium system reported ship position each 30 min very reliably but the ISAR never opened to take a sea temperature. This cruise was lost.
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We began the post-calibration at UW APL calibration bath (Jessup).
Acorr = 0.950, Offset = 0.12 C.
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The calibration bath was cycled between 5-30 degC in 2 deg steps. The plot here compares the bath temperature with the computed temperature from the real-time averaging program G08d. The best results use an interpolation coefficient of 1.012 and a final offset of 0.08 degC.
Acorr = 1.012, Offset = 0.08 C.
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The calibration bath was cycled between 5-35 degC in 5 deg steps. The plot here compares the bath temperature with the computed temperature from the real-time averaging program G08d. The best results use an interpolation coefficient of 1.008 and a final offset of 0.08 degC.
Acorr = 1.010, Offset = 0.100 C.