PFD Shows me on the runway, but not the map

[aeroaddict]

Running a full Dynon 2020 set up with a 10" HDX. I use Seattle Avionics for the maps. Been flying for about a year without issues. Recently I have noticed at my home base airport that has a helicopters school on one side and the planes on the other of the traffic pattern I will get 'traffic' warnings because the map will have me on the other side of the runway with the helicopters. When landing, the PFD shows me right on the runway. I have even (intentionally) crossed the center line and the PFD shows this. I have reloaded software (Dynon & Seattle) and verified the correct nomenclature and GPS pin position in the setup menus.

Any thoughts?

 

[dlloyd]

If the map you are referring to is the VFR chart, chart makers move things around a little to make everything fit. Yep the airport is not exactly where the VFR chart shows.

 

[aeroaddict]

Thanks, I understand your answer (yes VFR chart), but why then do I have 'traffic' warnings as it shows I'm on top of the helicopters? It seems like even though the map is a little off, the GPS would be accurate.

 

[GalinHdz]

FWIW; GPS receivers built before 2018 have a maximum accuracy of no more than16ft each way. This means at even best case scenario it can be 32ft off. Now this gets multiplied by map and display error. The smaller the total map area the better the display accuracy will be, regardless of how much you zoom in.

A 2% error in a 10mile chart is about 1,000ft. The same 2% error on a sectional (500,000 scale or about 200 miles) is about 4 miles. So a small difference (hundred feet or so) in position displayed between different maps is not than uncommon. We need to understand our equipment capabilities and especially its limitations.

 

[aeroaddict]

Agreed, but this is a new thing. Flew for a year and everything was spot on. Flew today and with the map zoomed in and zoomed out, and again my position is off.

The point being that I get 'traffic notifications' and the position of my aircraft is right in the mix, when I'm 1/8 mile or more on the other side; Upwind side vs Downwind side.

GPS is the 2020 version.

 

[GalinHdz]

Agreed, but this is a new thing. Flew for a year and everything was spot on. Flew today and with the map zoomed in and zoomed out, and again my position is off.

If this has just started happening then you should call DYNON Support, talk to them and see what they can come up with.

 

[Dynon]

I'm wondering if the a recent update to a chart had the geo-ref off just a smidge. Did it coincide with a chart update, by chance?

 

[aeroaddict]

I believe it did. I did talk with you guys to day and will download my last flight and then upload to Dynon.

Thanks