DFF-3D cross section display movement

[Snips]

Flowmotion,
The motion sensor in the transducer is pretty basic, but I would think that it would do better than what you are seeing. If you check the Mis-Match box that will tell us if indeed the motion is getting processed. It will either get better or really start moving around as the correction factor will be going the opposite direction.

Snips

 

[Iker]

All the offset are measured from the transducer to the CG (or to the GPS).
If your GPS and CG are located above the transducer, then you should use a + sign for both Transducer Position and GPS Position Up/Down.

Can you try the following parameters:
- Transducer Position Bow/Stern = -6.9ft
- Transducer Position Up/Down = 3ft
- Transducer Port/Starboard = 0.0ft

- GPS Sensor Bow/Stern = -12.5ft
- GPS Sensor Up/Down = 7.9ft
- GPS Sensor Port/Starboard = -2.6ft

 

[flowmotion]

Iker,
The transducer sign convention is different from Snips:
"Flowmotion,
Those will be better.

Transducer to CG
Stern +6.9
Down -3.3

GPS to Transducer
Bow -12.5
Up +7.9
Starboard -2.6".

Have you used these conventions successfully?

 

[Snips]

Flowmotion,
Iker and I chatted about your performance earlier this week while out on a DFF3D. I would but curious to get your feed back after you try his settings.

Snips

 

[MarMax]

All the offset are measured from the transducer to the CG (or to the GPS).

I think this is a key point. The transducer is the reference and measurements are from the TD to the CG or from the TD to the GPS. Even though the manual is clear on this, it sure confused me. I've gone through this 3-4 times now and hopefully I'm in the ballpark now.

The only remaining mystery is why the system is changing/rounding the offsets. (e.g., 8 vs. 7.9 and 9 vs. 8.9). Granted this is minor and probably does not make any difference. But these are computers after all and they are supposed to do what you tell them.

 

[flowmotion]

OK...it sounds like we are on the same page.

I will try the new parameters and see what checking the Mis-Match box does.

 

[flowmotion]

I was able to try the suggestions today.

1- I checked the mis-match box. there was some increase in the motion of the cross section. it was not large, but there was a change.

2- I corrected the signs that were incorrect for the transducer offsets bow-stern and up-down. I used the measurements from the gps to transducer and transducer to CG. the results were slightly improved. However, the cross section was far from motionless in a rolling 2' beam sea.

Unfortunately I don't have video of the result. It would be useful to get some videos posted of the cross section in various sea conditions to see what is nominal performance.