[Acoustics] Delay in GPS data processing

[Rainville,François [CIS-WSB]]

Hello all!

We have observed that GPS data is sometimes delayed and lagging with respect to the ADCP data collected.  This can be observed as a strange path that does not correspond well to the shape obtained by bottom track but which in fact corresponds to events (velocities) of moments before. This delay is sometimes quite small (by 1 second) and sometimes bigger (up to 15 s).  We have not yet been able to determine any trend in the type of computer and communication systems causing this to happen.  But this is definitly a problem we would like to resolve.

- Did any of you also witness such problems while using GPS?

- If so, can you provide a brief description of the type of computer used, communication ports (USB, PCMCIA, etc.), GPS receiver, output frequencies, type of modem radio link if any used?



Many thanks for helping us with this issue!

Francois Rainville
Water Survey of Canada
Environment Canada
373 Sussex Drive, Ottawa, Ontario;  K1A 0H3
Phone: 613-992-1673;  Fax: 613-992-4288