There seems to be very little detail I can find about how to connect and configure a GPS to allow operation in TRK or NAV mode. Can someone direct me? I have a D180 with no AP74 or HS34. The D180 does not seem to recognize when I connect a GPS that is out putting NMEA data.
GPS Connection
- Thread starter Garth
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Page 4-6 of the install guide covers this, and we also have a compatibility chart here:
http://wiki.dynonavionics.com/GPS_Serial_Compatibility_and_Configuration_Settings
http://wiki.dynonavionics.com/GPS_Serial_Compatibility_and_Configuration_Settings
Thanks, I was looking at an older version of the User's Guide.
But I see that the User's Guide indicates (or at least implies) that the $GPGGA is mandatory per the following from the guide:
To use the GPS-related features on your EFIS and/or EMS,
your GPS must output either “aviation format” or the
following NMEA sentences in its serial stream: $GPRMC,
$GPRMB, $GPGGA, and one of $GPBOD or
$GPAPB.
Whereas the Compatability Chart indicates it is optional, per the following:
GPGGA - Only needed if you want GPS altitude
Please clarify ... Thx.
Garth
But I see that the User's Guide indicates (or at least implies) that the $GPGGA is mandatory per the following from the guide:
To use the GPS-related features on your EFIS and/or EMS,
your GPS must output either “aviation format” or the
following NMEA sentences in its serial stream: $GPRMC,
$GPRMB, $GPGGA, and one of $GPBOD or
$GPAPB.
Whereas the Compatability Chart indicates it is optional, per the following:
GPGGA - Only needed if you want GPS altitude
Please clarify ... Thx.
Garth
- Joined
- Mar 23, 2005
- Messages
- 13,226
The compatibility chart says:
You don't need GPGGA to do NAV or TRK on the autopilot, but you need everything else. GPGGA is used for % power in an EMS if it doesn't have access to an EFIS.
You don't need GPGGA to do NAV or TRK on the autopilot, but you need everything else. GPGGA is used for % power in an EMS if it doesn't have access to an EFIS.
Put a direct-to to anywhere in the GPS. When the connection is working properly, you should see the ID and other textual info from the GPS on the HSI page.
Yes, those would be there too. No changes needed in the AP setup.
Update - I have been trying to use a tablet running Naviator to run the Dynon AP through a bluetooth to serial adapter. I can get the D180 to recognize the GPS signal/connection and operate in the TRK mode. In this mode the roll control seems more stable for the short period I ran this way. But it was not controlling per the flight plan set up through the Naviator software, but rather seemed to just track straight ahead when set. I'm not giving up yet since through previous communication with Naviator they advised that their software is only out putting two of the three data streams required by the Dynon AP software. This is supposed to be included in their next update due by year end. So the jury is still out as to how viable this is.
One reason I am trying this is because I am not happy with the stability of the roll control with the Dynon AP when in heading mode. This is still the case, ie I haven't found a sensitivity setting that adequately reduces the rolling effect. My question to Dynon is why does the roll control set up only have sensitivity as a single tuning parameter (not including torque) whereas the set up for pitch control has sensitivity plus 5 or 6 other secondary parameters? There is no slop in the aircraft controls and the altitude/pitch control works great.
Garth
One reason I am trying this is because I am not happy with the stability of the roll control with the Dynon AP when in heading mode. This is still the case, ie I haven't found a sensitivity setting that adequately reduces the rolling effect. My question to Dynon is why does the roll control set up only have sensitivity as a single tuning parameter (not including torque) whereas the set up for pitch control has sensitivity plus 5 or 6 other secondary parameters? There is no slop in the aircraft controls and the altitude/pitch control works great.
Garth
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- Mar 23, 2005
- Messages
- 13,226
Garth,
Roll in an aircraft is simpler to deal with than pitch, so it needs less adjustments.
The reason heading mode doesn't work as well is because it relies on the compass module. As you can see, when you have GPS track, the track hold works better. The AP software really doesn't know if it is getting HDG or TRK, so this means it's not that the AP is tuned wrong, but that it is reacting to the change in heading from your compass.
The compass is 3D, so even if it is perfect when you are level, when the plane rolls a bit, distortion above or below it can cause a heading change. The AP sees this, and then drives the airplane. Since the heading change was not real, but just induced by roll, the AP constantly hunts around. You may find that it's better or worse at some magnetic headings, which would be a good indication that you have 3D compass errors. This would be the reason a lot of competing autopilots require GPS to operate, so they don't have to worry about magnetic heading errors at all.
One option you have is to play with your compass location. The other option you have is to buy a $70 GPS "puck" and just wire that up and fly TRK when you aren't using Naviator.
Roll in an aircraft is simpler to deal with than pitch, so it needs less adjustments.
The reason heading mode doesn't work as well is because it relies on the compass module. As you can see, when you have GPS track, the track hold works better. The AP software really doesn't know if it is getting HDG or TRK, so this means it's not that the AP is tuned wrong, but that it is reacting to the change in heading from your compass.
The compass is 3D, so even if it is perfect when you are level, when the plane rolls a bit, distortion above or below it can cause a heading change. The AP sees this, and then drives the airplane. Since the heading change was not real, but just induced by roll, the AP constantly hunts around. You may find that it's better or worse at some magnetic headings, which would be a good indication that you have 3D compass errors. This would be the reason a lot of competing autopilots require GPS to operate, so they don't have to worry about magnetic heading errors at all.
One option you have is to play with your compass location. The other option you have is to buy a $70 GPS "puck" and just wire that up and fly TRK when you aren't using Naviator.
Thanks for the explanation.
Is the AP software looking at instananeous heading changes or averages over say 5 or more seconds? Just thinking if there may be some way to buffer out the background variation.
Can you provide more info on your "GPS Puck" idea? Are you talking about a simple stand alone GPS reciever, which I have and used it for a while (via bluetooth) with my new model Nexus 7 tablet (when the latter was first released it's internal GPS had stability issues which were later fixed by a software upgrade). If this was "wired" to the AP would the TRK option show up on the AP/D180 menus? How would it know what Track to follow if there is no flight plan/no navigation program running?? How would it wire to the serial connector, I think the GPS just has a mini USB connection. I could also try the bluetooth option since I have already invested in the adapter.
Sorry for all the questions, but if I/we can get this to work it should be useful for others as well.
Thanks, Garth
Is the AP software looking at instananeous heading changes or averages over say 5 or more seconds? Just thinking if there may be some way to buffer out the background variation.
Can you provide more info on your "GPS Puck" idea? Are you talking about a simple stand alone GPS reciever, which I have and used it for a while (via bluetooth) with my new model Nexus 7 tablet (when the latter was first released it's internal GPS had stability issues which were later fixed by a software upgrade). If this was "wired" to the AP would the TRK option show up on the AP/D180 menus? How would it know what Track to follow if there is no flight plan/no navigation program running?? How would it wire to the serial connector, I think the GPS just has a mini USB connection. I could also try the bluetooth option since I have already invested in the adapter.
Sorry for all the questions, but if I/we can get this to work it should be useful for others as well.
Thanks, Garth
By $70 puck we mean any of the OEM GPS receiver/antenna combos that can spit out RS-232. You'd hardwire that in to the D180 like you would a portable. If you had such a receiver, you'd be able to fly TRK on the AP. http://amzn.com/B0016NYHVS is an example of one.