My findings on GPS SHTUFF....

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OK, so I've been limited in my flight time here in the PNW, but I did manage to get a few test flights in with several different GPS modules.

Clear sky, sunny day, 12 midday flights. Please note that the drones were turned on for about 10 minutes, left sitting at the launch area, turned off, and then turned back on again. Each drone was then flown straight up to about 380ft AGL, would hover there for about 10 minutes before being brought back down. Each drone has the Rev 2 shield from 3DR. Flight area faces North with no large obstructions in the way, however to the East and West there are large buildings and tree's, to the South there is a very large hillside covered in tree's that probably goes up to about 500ft.

Rev A: Not going to bother putting on back in a drone for testing just because they are so god awful. Previous experience had me waiting 5+ minutes for a GPS lock IF I got one at all.

Rev B: Would get about 12 -13 Sats with a 1.1 HDOP. 2 and a half minutes lock on time though.

MRO Original: Surprisingly got 18 sats with .08 HDOP. Was quite impressed. However did take about 1 minute to get enough sats to take off.

MRO new version: Fluctuated between 19 and 20 sats with a .06 HDOP however, it did take about 30 seconds to get a sat lock before flight was available.

HERE GPS: Hit 19 sats with a .06 HDOP, however unlike the MRO, it achieved lock pretty much after hitting the power button which was pretty darn impressive.

I did notice that will all the drones, there was some slight drift when up in the air hovering. It wasn't terrible but if I had been recording a time lapse at the time, it would have been quite obvious. It wasn't windy or gusty that day so maybe it's just as good as any of the GPS modules get.

For me the winner was the HERE GPS. Maybe because the mast raises it above the body, but the near instant lock was a welcome feature (it also looks pretty sweet).

I didn't get to do a more in depth test as I was freezing parts of my anatomy off at the time, however I'm thinking of setting up a cable cam and having the drone fly about 400 ft left, return, 400 ft right, return and watch the HDOP and number of sats. I'd also like to run this test again but on an overcast day just to see how things go in not so optimal conditions.

With each drone, still had to land manually as once it was nearer to the ground the GPS signals became erratic and the drones would drift left, right, forwards, backwards... with manual control I was able to compensate though. Again, this is more geography based PITA (pain in the a**) than a fault with the GPS (wasn't someone supposed to be working on an optical sensor for us to help overcome this one?).

Overall thoughts are this. If you live in an area with poor GPS signal, you'll want to upgrade to the very best GPS system there is, but realize that you're still going to have issues every now and then. However, if you don't live in an area with poor GPS, then you could get away with a Rev B board easily. Although since the cost of upgrading is cheap, you might as well go ahead an upgrade.

On the upgrades available themselves....

The original MRO chip was an easy plug and play solution, however it did lack a USB socket with which you could connect to it for fine tuning, making changes etc. Not so with the new MRO! Now it's got a USB interface that you can plug directly into............ providing you haven't put it in your drone. You see the little enclosure that the GPS chip fits into has a back wall, and three struts (one left, one right, one front!). However due to the way the MRO chip fits into the drone the front strut sits right in front of said USB connection and renders it unusable while in the drone (unless you want to start cutting off parts of your drone, but then you'll want to probably replace that front strut with two other struts on either side.... and who wants to do that modification...). Point being you'd think a chip made for a 3DR solo by someone who used to work at 3DR would have taken this design issue and maybe offset the USB interface so it was actually accessible.

The HERE system does require a bit of DIY. I believe Jesters Drones used to supply a custom GPS cover with the here system but then stopped doing so (cost, or time of customizing?). As a result, you will be required to do a slight modification do your drone's GPS cover (ie. drill a hole in it and then smooth the edges out). It wasn't difficult with the help of my trust Dremel, but I can see some people maybe having issues doing this (look, if they can't follow instructions for doing a very very easy software upgrade, do you really want to trust them with power tools?). Also if they don't smooth out the holes, it's possible the soft wires that connect the Here to the Solo could get frayed. Shouldn't be an issue if you're leaving the GPS in place, but if you're taking apart your solo on a regular basis or having vibration issues..... who knows?

So hey, if you have a solo, want to upgrade it, the GPS is a worthwhile place to start, but for the love of god, don't pay $80 for a Rev B upgrade (saw one for about that price on Ebay), you're just being ripped off!
 
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Thanks for the great info. I'm still waiting for above freezing temps to test my new Solo out. But I'm reading everything I can to prep. I'm curious about the landing issues you mentioned. I've read a few of the other posts regarding landings and I'm wondering if it's better (as a new Solo pilot) to start out using the "auto" land or to start or doing landings manually? I have allot of landings south toy grade quads but this is my first gps based model. Any thoughts?
 
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Thanks for taking the time do this.
I'll probably put the results into an excel file and then keep updating based upon further flights so there's something a bit more up to date and with various flight conditions to compare to. Yeah.... I'm a bit of a nerd that way....
 
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The HERE kit is easily the most worthwhile modification I've done to the Solo (besides Open Solo of course).
I love the look of the HERE kit and the flashing LED's give good secondary feedback. We're all grateful for the Open Solo update, can't wait to see what's coming down the pipeline!
 
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Thanks for the great info. I'm still waiting for above freezing temps to test my new Solo out. But I'm reading everything I can to prep. I'm curious about the landing issues you mentioned. I've read a few of the other posts regarding landings and I'm wondering if it's better (as a new Solo pilot) to start out using the "auto" land or to start or doing landings manually? I have allot of landings south toy grade quads but this is my first gps based model. Any thoughts?
Honestly (and I think everyone will say this) start learning to fly manually ASAP. I'm not saying fly manually all the time, but practice so that when you need to take control, you will be in control. The Autoland has vastly improved with Open Solo, however with the stock software I found the drone would descend too quickly, bounce off the ground, tip over & bye bye props....

Manually landing also gets rid of the chances of you losing GPS signal and crashing when you're near the ground (due to tree's, buildings and other structures blocking the signal). Practice in an open wide area, and just get the feel for the drone, I'd even concentrate on just hovering in place with manual enabled, just so you get used to compensating for wind/drift. You can always reengage one of the autopilot modes if you need to. The more you practice, the better you'll be.
 
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Thanks! The more reading I do (mostly on this forum) the more horror stories I come across where pilots didn't follow the guidelines and the autopilot stuff takes over causing damage. I printed off both the user manual and service manual and have been spending a lot of time reading up on everything 3DR says SHOULD happen in the different flying modes. At this point practice must happen. (weather permitting that should happen in the next days)
 
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There is nothing you would ever need to mess with in there. Hence why I say it's a sales gimmick. Of course you CAN go in there, I don't mean that it's a fake. But there is no reason to and nothing to be gained.
 
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There is nothing you would ever need to mess with in there. Hence why I say it's a sales gimmick. Of course you CAN go in there, I don't mean that it's a fake. But there is no reason to and nothing to be gained.
Isn't that the only way to turn on the Galileo satellites? I read in several places that they did not come enabled after all despite some mRo statements to the contrary.

I'm only getting 16-18 satellites out of the box. Shouldn't I be getting 20+? I don't think Galileo is enabled on these at the factory.
 
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My mRo's are all installed as delivered. I get 18 - 20 on the ground and once at altitude its not uncommon to have 25+. HDOP often is in the high .4's or 5's. HERE is working great for me also.
 
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From mRobotics website:

"The mRo GPS NEO-M8N is a professional grade, notably robust GPS system capable of using USA (GPS), Russian (GLONASS) and European (Galileo) constellations at the same time. You can optionally enable the Chinese (Bai Du) constellation in exchange of disabling GLONASS.
This solution will provide you with an astonishingly accurate position and fast satellite acquisition. Our testing in SOLO gave us an average HDOP of '0.6' which is considered ideal conditions. Also, we were able to fix 20 satellites out of the box and with no shield (Clear sky conditions, shielding not needed but recommended)."


I think the usb port is used to enable/disable sattellites. I haven't tried this though.
 
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It's for many things. Again none of which are necessary or useful for the purposes of a solo or most any other small UAS. Sales gimmick.
 
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I think the usb port is used to enable/disable sattellites. I haven't tried this though.
You can use also use u-blox u-center over MissionPlanner MAVSerial Passthrough (CTRL+F, enable button on left column). Be advised that you CANNOT update the firmware of the GPS boards this way, they must be connected directly to the computer.

Aside from pushing updated firmware (if available), I use u-center to tweak some options (# of SBAS channels, sample rate, etc).
 
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You can use also use u-blox u-center over MissionPlanner MAVSerial Passthrough (CTRL+F, enable button on left column). Be advised that you CANNOT update the firmware of the GPS boards this way, they must be connected directly to the computer.

Aside from pushing updated firmware (if available), I use u-center to tweak some options (# of SBAS channels, sample rate, etc).
I cannot get the Mavserial pass through to work at all. Is there some indication that MP has opened port 500?
 

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