Event details
| Voyage: | IN2015_V02 [details] | ||
| Subject: | Issues with 150kHz sADCP | ||
| When: | 2015-05-17 21:59:13 UTC - entered into Elog/Everlog as 2015-05-17 21:59:13 | ||
| Log: | in2015_v02 | ||
| Equipment: | ADCP
75/150 KHz ADCP [view] | ||
| Station/Location: | EAC off Brisbane | ||
| Position: |
Latitude: -27.10117 Longitude: 155.315
- entered into Elog as 27 06.07S, 155 18.9E | ||
| Action: | noisy | ||
| |||
| Comments: | As we acquired and process the sADCP data we have noted some issues with the OS150kHz 1. Slight misalignment - fixed in config file (see previous log entry) 2. Interference - clear interference is seen in the beam echo amplitudes from some other acoustic device on the ship. (see page 14 of the Test Procedures in the OS manual. RDI notes that interference biases the data and should be prevented where possible. Whether this can be removed in post processing we do not know. 3.Ringing - the solutions in the bins above 35m-40m have unrealistic shears and large solution errors, and are basically useless. This is a signature of ringing (see OS manual Test Procedures page 15). The ship's engineers say that these adcps are directly in contact with sea water (with no cover) - thus the problem is not due to any 'cover' but is more likely due to a badly manufactured transducer head. These can be relatively easily fixed (the mooring team has done it a lot). I suggest the transducers get fixed as soon as possible. The main reason we have a 150kHz instrument is to sample the near surface shear that the 75KHZ cannot sample. | ||