|
|
|
There are two hardware problems which show up at different times in the SABL VTMX data set. The first problem at the start of the project is with the laser q-switch. The q-switch is not operating properly and the laser sends out several small pulses rather than one large one. Examples of how the q-switch problem affects the data can be seen in the data from October 2 around 1628 and on October 5 at 0325. The q-switch driver was replaced but the problem persisted so the laser head was replaced. The q-switch problem was not observed after replacing the laser head. The second laser problem was a coolant/temperature problem. There was a coolant leak that would allow the laser rod to slowly overheat. This is evident in the energy of the laser slowly degrading over time (usually a few hours). The first cure was to add more coolant (a mixture of 50% water and 50% glycol) and this worked until the leak became more severe. The leaky connector on the back of the heat exchanger/pump unit was then replaced and this helped but laser power problems persisted until the end of the project. There is one software problem which users of original data tapes and bscan format data sets need to be aware. The date in the data files needs to be examined carefully to be sure that it is correct. The initial date at the start of bscan files or on the data tapes is usually but not always correct. The date then backs up one day and is incorrect. The NETCDF format data has been corrected so that all the time/date information is correct. The following is a listing of some of the time periods where the q-switch or laser energy may have been a problem. The SABL data user should be aware that this list is not intended to be totally inclusive of all data problems. It is the responsibility of the data user to examine all the data carefully. Questions about the data should be directed to the RDP data manager. | |||
|
TAPE/IOP SPECIFIC PROBLEMS | |||
TAPE / IOP |
DATE |
TIME |
PROBLEM |
|
P62070 / IOP-1 |
2-3 Oct 2000 |
1628-1630 1710-1724 |
q-switch problem q-switch problem |
|
P62071 / no IOP |
3-4 Oct 2000 |
1802-2003 2030-2126 2156-2240 2254-2325 |
no lidar data q-switch problem q-switch problem q-switch problem |
|
P62072 / no IOP |
4-5 Oct 2000 |
1958-2112 0748-0750 |
q-switch problem q-switch problem |
|
P62073 / no IOP |
5 Oct 2000 |
. |
no problems |
|
P62074 / no IOP |
5-6 Oct 2000 |
. |
laser energy a bit low some subtle anomylies that may be q-switch problems |
|
P62075 / IOP-2 |
6-7 Oct 2000 |
1854-1904 1955-2000 0034-1802 |
q-switch problem receiver convergence q-switch and energy problems |
|
P62076 / IOP-3 |
7-8 Oct 2000 |
2154-2215 |
q-switch problem |
|
P62077 / IOP-4 |
8-9 Oct 2000 |
1834-1858 1910-1928 0000-0046 0350-0400 0508-0532 0605-1012 1315-1335 1428-1448 1526-1548 1622-1648 1654-1658 |
q-switch problem q-switch problem q-switch problem q-switch problem q-switch problem q-switch problem q-switch problem q-switch problem q-switch problem q-switch problem q-switch problem |
|
P62078 / no IOP |
9-10 Oct 2000 |
. |
q-switch and energy problems rain intermittant all day |
|
P62079 / no IOP |
13 Oct 2000 |
1040-on |
laser energy gradually decreases |
|
P62080 / IOP-5 |
14-15 Oct 2000 |
. |
laser energy low - weak signal |
|
P62081 / IOP-6 |
15-16 Oct 2000 |
before 2100 after 2100 after 0200 |
laser energy low - weak signal very weak signal q-switch problem |
|
P62082 / no IOP |
16-17 Oct 2000 |
before 0030 after 0030 |
q-switch problem - no lidar data laser energy low - weak signal |
|
P62083 / no IOP |
17-18 Oct 2000 |
before 1930 after 1930 |
laser energy low - weak signal laser energy very low - very weak signal |
|
P62084 / no IOP |
18-19 Oct 2000 |
2140-0100 0100-0450 0450-0940 0940-2030 |
very weak signal weak signal very weak signal weak signal |
|
P62085 / IOP-8 |
19-20 Oct 2000 |
. |
weak signal |
|
IOP-9 |
21 Oct 2000 |
. |
downtown Salt Lake City tracer study - no lidar taken |
|
P62086 / no IOP |
23-24 Oct 2000 |
. |
weak signal |
|
P62087 / no IOP |
24-25 Oct 2000 |
1840-0040 1955-2017 0040-0210 0210-1714 |
very weak signal no lidar data weak signal very weak signal |
|
P62088 / IOP-10 |
25-26 Oct 2000 |
1730-2022 2022-2200 2200-1725 2206-2212 2244-0135 |
no useable return signal weak signal very weak signal no lidar data no lidar data |
|
P62089 / no IOP |
26-27 Oct 2000 |
1730-2022 |
very weak signal |
Last modified: June 14, 2000
VTMX 2000: SABL Known Problems