+- MacSailing.net (https://macsailing.net/mybb)
+-- Forum: iPhoneSailing.net (https://macsailing.net/mybb/forum-14.html)
+--- Forum: iNavX (https://macsailing.net/mybb/forum-15.html)
+--- Thread: Compass Conflict (/thread-1184.html)
- drctdby - July 17, 2010
I used the app for the first time on a trip. On the first leg I was not navigating to a particular waypoint and noticed that the ribbon compass at the top was completely different than the digital "Heading Magnetic" read out of the heading I was on (the digital was correct).
On the next leg I navigated to a waypoint and they were in sync. What am I doing wrong? I did have the "Pos. Icon Kept Visible" off. Did that have something to do with the problem?
- GPSNavX - July 17, 2010
Not sure as the compass banner uses the HDG: (or if disabled in the "Setup" it uses COG
If the HDG: compass error is greater than 30 degrees then the banner will be plotted in yellow.
- drctdby - July 17, 2010
I did have the HDG disabled. I have changed that and on the next trip I'll let you know if that corrected my problem. Also, the ribbon compass was not yellow.
- GPSNavX - July 17, 2010
HDG: = Heading
COG: = Course Over Ground
If HDG: is disabled, then COG: is used for the compass banner and HDG: is not displayed in the Instruments. COG: does not provide any error (other than HPE: horizontal position error) and hence the compass band would not be yellow.
HDG: uses the magnetic compass in the iPhone or iPad, where COG: uses the GPS in the iPhone 3G/3Gs/4 or iPad 3G. In order for COG to be calculated accurately: one must be underway. Where HDG: is dependent on how the device is oriented independent of motion.
http://support.apple.com/kb/TS2767
- AugustH - July 18, 2010
I've seen the compasses in the iPhone and the iPad, side by side but not close enough to affect each other, to be different by 30 degrees or more. Use a real compass to align them to North and they're pointing in different directions, neither of which is north. I would not trust the compass in either device, and since there's no way to calibrate them the problem cannot be fixed.
- drctdby - July 18, 2010
Thanks AugustH. In my situation, above, The digital COG was correct. If the digital read out receives its information from the GPS if the HDG is disabled (COG enabled) does the ribbon receive the same GPS information? If so, how is it that the ribbon can be so far off the correct COG while the digital is correct? If not (the ribbon gets its information from the iPad compass), then you've explained a problem that can't be corrected unless the ribbon can receive information from the GPS.
- GPSNavX - July 18, 2010
Yes the compass banner will use GPS COG: instead of compass HDG: when HDG: is disabled.
- drctdby - July 18, 2010
Thank you. As I said, I'll check out the various configurations on my next cruise and will let you know the results.
- drctdby - August 15, 2010
Just came back from a week in Maine. Everything works perfectly. This app is a must have if you have an iPad!