Due to the poor GPS performance of the Iris and issues on some of them where the GPS presses down on the Pixhawk causing a wide array of other issues, i just ordered a mast kit for the Ublox GPS.

It will take custom cuts int the top cover so it will have a slot for removal but I'll figure it out when I get all the parts.

My GPS has been sent back for replacement and I have asked 3DR not to remove the protective cover from the new GPS. If they don't follow those instructions I won't be able to use the mast kit.

Anyone else tried this? 

Mark Prince

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That's a very interesting idea and project!

Two ideas in interim steps:
- You could start by solely cutting a hole in the top hull for the GPS/Magneto. cables and then glue (double sided sticky tape) the GPS module in its cover on the top hull.
That would be easier to implement and only add a little bulge to IRIS. Still the GPS module would be raised by a few mm if not even cm.

- Next you could glue the mast on top of the hull and use the same hole from before to run the wires up. The question is whether the cables will be long enough for that.
But it would give you the maximum possible distance for the GPS from the ESC.

Mounting the mast on the top board would also be possible, but then you have to cut a hole through the hull to let the mast through. That will end up being painful for assembly/disassembly.

Another idea would be to leave away the top hull altogether and tape everything left in it (FrSky radio, safety button, loudspeaker) to the top board.

Let us know how things go. That will be interesting.

they normally just send out the GPS retail kit  for GPS replacements which has the GPS in the 3DR case..at least mine arrived that way. I also  ordered a mast but since I have been experimenting with Pregnant IRIS for increased battery space I have now boosted the top cover up 10mm also. I would love to find or make an STL file for a Vacumn form mold so that I could alter it to provide for covering in the expanded body cases..

       hzl

Right now my concept is to mount the mast base on the top board in front of the Pixhawk.

The Ublox mast kit allows the mast to be folded down for transportation and convenience.

I plan to cut a slot the width of the mast in the cover from where the mast protrudes through the cover all the way to the front edge of the cover. This would allow the mast to be folded down towards the front allowing the cover to be easily removed. 

Thats the plan anyway. Once I get all the pieces delivered and laid out with a couple of creative Budweiser tall boys I might think of something else:)

mp

HZ,

Do you have any pics of the pregnant Iris? I ordered some 8mm spacers for the top cover in case I decide to go that route.

mp

Please post photos when you figure out the setup that you're going to use.  I've been tinkering with the idea in my head, so I'm stoked to see what you come up with.

 

 

 

My mast came in and I've figured out exactly how I'm going to doit. The GPS cable that comes with the ublox mast kit is 12" long but the I2C cable is only 7" long. Don't understand why because you need both of them which will make the installation tight on the I2C cable but I think I can make it.

Problem at the moment is I don't have a GPS. I sent it back for replacement and they have not shipped the replacement as of today. I will still make the cut in the cover this weekend. I need a table saw to make a perfect cut and a neighbor down the street has one. The mast thickness is 4mm so I'll make the cut about 7.5mm to 8mm to allow for the cables. The pic below shows how the mount will look when the mast is upright.

 The next pic shows how the mast will be positioned when folded down.

I'll cut the slot from the top center center of the cover all the way down to the starboard side of the cover. That way you can fold the mast down and the remover the cover easily.

After I make the cut I'll send a pic of how the mast will look upright and folded with the Iris cover on.

After that I'll be waiting on the replacement GPS.

mp

Looks good so far! How is the engagement on the mast when moving the mast into the upright position? Does it snap or pop into place?

Yes it snaps into place. By my estimates the slot I cut will not intervene with the thread bulkheads of the original GPS mount. It will however come pretty close to the thread bulkhead for the cover screws.

I first considered folding the mast forward but then the GPS hangs out with no support when folded down. With the planned method the GPS housing will rest on the motor arm not causing any stress on the plastic mast when transporting.

I'll also have to make an adjustment to the compass parameters since the compass will be rotated 90 degrees relative to the stock installation.

Yes, I will have a hole in my cover but it's bound to help the GPS performance which has been randomly poor while also solving the space issue between the Pixhawk and the GPS. 

Definitely let us know what change in HDOP you observe as a result of the mod!

I've made the cut in the cover and this is what it looks like with the bare mast. The GPS is supposed to be delivered today or tomorrow. Once I get everything permanently mounted and wired up i'll post a pic with the cover and without.

Success! I have a functioning mast on my Iris.

I got hdop of less than 1.5 sitting in the driveway. First flight went good but the jury is still out until I get 7 to 10 flights on it.

My first test was tonight(hover only) and it was the first time I have ever maintained <2.0 hdop when the Iris was off the ground. As low as 1.35.(log file is attached.)

See below for a couple of pics with the mast upright and folded down.

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