DVL1000 Data Questions

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DVL1000 Data Questions

Posted by Michael Borghardt at November 24. 2017

We are currently using your DVL100 in one of our hovering underwater vehicles and we have having some difficulties.

 

Right now our DVL valid bits go in an out when we are close to walls. We have mounted the unit horizontally. We wish to use the distances from the wall and get accurate velocities.

 

 

Questions

 

What does does figure of merit mean? it is in units of m/s. An invalid estimate is set to 10?

 

Does the valid flags in the data packets mean that I do not need to check for invalid velocities(-327768.0) or range(0) is the valid fields are false or do I need to look at both.

 

It the velocity valid in X then I be sure the velocity will be valid? Do I also have the check the fom in X too?

 

How does the status valid FOM in X,Y, Z1, Z2 relate to the FOM value?

 

Can we do water track and bottom track at the same time? 

 

 

 

 

 

 

Re: DVL1000 Data Questions

Posted by Magnus Gr√łtterud at November 28. 2017

Hi Michael,

I recommend both the DVL Operation's manual and the DVL Integrator's Guide available for download from our beta website, or here on the current web if you wish.

1. The Figure of Merit is a "measure of the velocity white noise level (single ping precision)". FOM is a particularly useful parameter to incorporate into a Kalman filter.

2. If the status bit indicates it is invalid, you do not need to check the value is set to invalid (f.ex Beam 1 velocity = -32.768).

3.  The velocity will still be valid, but FOM will indicate whether it is a more or less precise estimate.

4. If the FOM is invalid (0) then it will be set to 10. If it is valid then the value will vary depending on the precision.

5. Yes, the same ping will be used both for bottom and water track.

Let me know if I misunderstood any of your questions.

Best regards,

Magnus

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