I need a replacement GPS, I LOVED the old "small" mtek GPS (this plus this) but 3DR is no longer selling them as a unit. The new "large" GPS units don't fit my model very well and I don't need a battery backup.
I've found this on JDrones site:
Can anyone say if that unit is the same as this from 3DR, but just without battery backup?
Would I need to load new firmware to avoid the additional messaging or is it safe to fly like that out of the box?
Looks the same as what I got with the original APM 2.5; it's fine, go for it if it suits. What "additional messaging" do you mean? You might want to update the firmware for it, instructions are here in the wiki.
Battery backup is pretty annoying to not have for most people, but if you don't want it... I can certainly say that that smaller GPS board benefits a lot from a better ground-plane, which V2 has (I've never tried this version). So IMO V2 is a better unit for most people. Can't figure out why jDrones removed the battery, just about every other 3329 variant has one, for good reason (oh wait...it's so they could sell you the battery later lol).
My GPS locks within 20 seconds - by the time I'm ready to launch, it's got 12 satellites, so I'll happily sacrifice battery in favour of smaller size.
The additional messaging - I remember reading that the stock firmware sends out messages for signal quality (I forget the name of the messages) and it reduces refresh rate. However this point is moot since you say one can upgrade it's firmware.
That is an incredibly quick cold-start time. Mine takes longer than that when going from my home to field, even though it's less than 1 mile away. And that's with battery backup. Without backup it takes a lot longer than that, several minutes IIRC.
Adding a backup battery later is trivial and costs maybe $2, so really not an issue anyway. I went that way because jDrones optional battery backup board would have gotten in the way of my added-on ground-plane, plus this allowed me to put the backup battery wherever I wanted it. Good luck with it.
Thanks Craig. I've been through 3 of these small GPS units on my APM 1.5 and they all worked great - my friends that fly ArduCopter has to wait a few minutes (an eternity ;) for lock before they can fly - I always assumed it's because of the difference in code - a multirotor needs a more accurate lock than a plane.