I was wondering whether anybody else has been experiencing weird offsets in either latitude or longitude coming from the mediatek GPS? Strangely, it only seems to occur when it runs in binary mode and with NMEA I get way better accuracy. In my case I run it with the libraries from the ArdupilotMega repository and using the DIY drones adapter board. I get a 0.4 degree longitude offset (approximately) when running in binary mode. That translates into an error of over 10km or so I think.
I understand that most of the code is still under heavy development but since I suppose feedback is welcome I thought I ask here. My first guess would be that there could be a problem in the GPS parsing code or on the mediatek firmware. On an unrelated note, my mediatek does not seem to store settings when powering down (although I use it with the adapter which has a battery on it).
Andre
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I'm also testing the MediaTek (binary output) using ArduPilotMega 1.0 library test software, indoors in a single story wood frame house near a window facing south. I'm having difficult getting GSP lock, which indicates that the unit is not as sensitive as advertised. In addition to this, when I do get a solution, the reported latitude is right on the mark, however the longitude is more than 20 deg in error. I'm certain that Jordi's blog will provide the solution to this issue.
If you have access to NOTAMS (notice to airman), it has directs to block GPS satellite 25 from your aircraft navigations systems. It does not say why you shouldn't use it, but it may be inducing errors in these positions.
I am looking up the specific notam. I will post what i find.
Joe
B5 62 01 05 02 17 09 B5 D2 65 32 45 00 00 04 71 00 00 00 00 0A E7 6A 10 09 03 0C 46 5C EC 11 9A
the gps location is Latitude 35.0642 Longitude -76.9532