Had a chance to compare the Naza M to AMP 2 this weekend and wanted to share the experience.
The comparison was done on two similarly sized custom built quads at ~24" span running the same props, motors, PDU and ESCs. The Naza quad had a Go Pro and Fat Shark FPV 5.8Ghz Transmitter and weighted in at about 3.1 Lbs. The APM Quad (mine) had no additional equipment besides a Sonar and it weighed about 2.75 Lbs.
In general both performed very well with a nod going to the Naza in Loiter, RTL and auto landing due to what appears to be a better GPS. Clearly APM has auto mode and Naza does not.. for the price the APM appears to be a solid value.
As expected both quads were equally stable with no real noticeable difference in stability. The only big difference was NO TUNING on the Naza... it just worked out of the box.
The Naza quad had a noticeable difference in loiter stability and accuracy. Granted my quad my not be tuned perfectly but the Naza held its position more accurately and with less twitching in the wind to do so. The Naza's corrections to the wind seemed to be invisible.. where the APM corrections were noticeable in both pitch and prop noise.
We did a RTL comparison taking off from the same spot and flying about 100 yards away at about 35 feet. The Naza returned to the exact spot of take off. APM got within 10 feet (see below).
Testing the auto landing during RTL..... the Naza descended from 35 feet in what appeared to be about 5 foot increments. It was a very controlled decent. It landed perfectly on home and shutoff. As mentioned the APM quad hit the launch point within 10 feet. Its decent to landing was steadily and constant. When it touched down it then proceeded to skip around on the ground and went another 10 feet from its landing point before shutting down.
The Naza has no autopilot. I finally got all the gremlins out of my APM and flew several successful missions which was very cool.
APM is ~$200 with GPS and Autopilot
Naza is ~$240 + and additional ~$160 for GPS. = $400
Great comparison, John! I've been hoping someone would do that (I don't have a Naza myself). I think we should benchmark against DJI and endeavor to match their performance at a fraction of the price (and with an open platform). Sounds like we have some work still to do, but I think we're closing the gap.
I'd love you to do the same test on the next version of the code (2.9) when it's out in a week or two. Also: are you using the uBlox 6 GPS? That will give much better loiter/autoland results than the built-in MediaTek. If you don't have that, I can send you one so for your next test.
Glad to do some additional testing on 2.9. In terms of the uBlox.. I bought one a few days ago taking advantage of the sale... so no need there but thanks for the offer.
I would say the the ability to run missions on the APM is certainly a huge differentiator and value adder... the downside is the tuning. For those who like tuning.. no issue.. for those who simply want to fly its a drag. I have had my APM 2 since April and I am really just now starting to get really comfortable.. and that was after a few set backs and a few months on the shelf. (Note I came from the multi-wii platform so I was not really starting from scratch) . The Naza came out of the box and was running great from flight 1.
Your goals of matching performance at half the price is a fantastic goal. I think the gap is closing. It seems every release some things get better some take a step back.. but the progress is certainly steady. The team has a lot to be proud of and a lot to work on.
Personally, I think APM has much more upside. Being able to run missions, interface with other sensors, the open possibilities of the code and trigger servos (once that is fixed) are features that would keep me interested. Naza flys great and if you can match that with the added functionality APM has, there would be no question as to the value.
Did some additional "testing" and comparison to the NAZA the other day.
I installed the UBlox GPS and the performance in RTL has improved significantly. The quad returned to within 2 feet of the launch and the rate of decent and landing were nearly comparable to the Naza. No more skipping around when it landed.
I recently started FPV on this Quad and the learning curve is steeper than I thought it would be. My friend is also learning FPV on his Naza quad and one feature that seems to help him quite a bit is flying around in Loiter / GPS Hold.
On the Naza this flight mode gives rock solid altitude and position hold even at low altitudes and the quad is still flyable. Let go of the sticks and it is "stuck" where you let go. This is helpful in FPV as I found some disorientation and difficulty gauging rate of ascent / descent. Stopping to collect your thoughts without the fear of the quad drifting around or changing altitude is very comforting.
With the APM in loiter or Alt Hold modes you loose a lot of control on the altitude adjustment. This is fine if you are flying in wide open spaces but if you want to change altitude for any reason you need to change out of the flight mode and reset your altitude. I know you can adjust altitude in these modes, but when you switch out of them your Quad is either falling to earth of flying away really quickly.
With the NAZA you can simply adjust altitude in GPS hold and the quad adjusts appropriately.
Flying in loiter mode is doable but it feels different. When adjusting the position in loiter my quad seems to want to "rebound" back a few feet. With the Naza the quad simply stays where you left it.
I know I am probably comparing apples to oranges in the way APM and NAZA handle adjustments to Loiter / Alt Hold, but personally I think the way NAZA approached them is a bit more intuitive. Since you can essentially fly in GPS Hold on the NAZA there really is no need to switch out of it and if you need to you can just let go of the sticks and the Quad will be where you left it.
I also know I am probably trying to get the APM to behave in a way the flight modes were not intended so the comparison may not be fair in those regards either, but a new or improved flight mode that behaves the way the NAZA does would be beneficial to me.
I certainly agree with you regarding flying in the Loiter mode. Having seen the way the Naza functions, having that locked feature would really be the icing on the cake
APM Auto Landing: "When it touched down it then proceeded to skip around on the ground and went another 10 feet from its landing point before shutting down"
This is exactly the same behaviour on my quad. APM never shut down motors at first contact with ground. When is trying to skip around, then it can flip since the some arms could have ground contact.
When I do Auto landing, I did switch myself from Auto to Stabilize and lower the throttle stick in the same time, to avoid jumping (and flipping).
Is any solution to assure that once the ground to hit, to stop automatically (some PID adjustement) ? Otherwise I can not trust a real Auto Landing without my manual intervention.
Makes sense to add ACC feedback to autoland... when Z gets a "hit" upon impact, the motors disarm. Actually I'm quite surprised this isn't already the case.
While naza GPS mode can help in some situations, most of my 'naza buddies' say alt mode is more practical for everyday FPV (because it's more responsive in X/Y). That said, my APM2.5 holds a loiter as good as naza... it's just the alt hold that gets larger errors when accelerating around (talking 1-1.5m max). I have a personal agenda to bring buyers remorse to my close buddies who fly naza... I'm a newb with autopilots, but I can assure you I have good piloting skills, and I've already logged plenty of tuning time. I think all I need is better info to get there. ;)
Unfortunately the tuning process has turned out to be very much guess and check affair. Existing info on tuning alt mode is too limited and vague. I think Dave C's rate/stab tuning guide is along the lines of what we need... a layman's guide with info on what to look for, more exact descriptions of what each parameter does, and of course discovery of independent parameters (like Dave observed with "rate D"). Recently throttle acceleration got thrown in to the mix... just more variables on top of this black box. The subject of alt mode tuning needs a lot more clarity.
The APM is not coded to automatically shut your motors down. This is to keep your quad from falling out of the air at 1 meter if your sonar is off :)
However seeing that the APM is open source, you can simply go change that in a couple of lines of code. I read that someone built a toggle switch which he placed on the bottom of quad to verify that it had landed, and it was safe for the APM to shut the motors off.
Good idea with adding an extra Z measurement Kevin.
Could you please elaborate how to add this feature in Mission planner?
I would like to be safe to know that an auto landing does not suppose a new jump to another position.
I understand where you are coming from; I wouldn't want sporadic ACC noise to send my quad on a 30m freefall. I can see why this isn't "built in".
I also have both, came from a NAZA-M, the APM is more like the WooKong-M because the WK has way points but the WK is really expensive, more expensive than I want to spend for fun in the park.
That being said I agree on all points, but the thing that I like the most about the NAZA is flying with GPS mode, in fact you can start without GPS with the NAZA-M and it will drift but when GPS gets signal it will start to hold. Any one can fly the NAZA its so good. From my experience, and correct me if I'm wrong, but the APM has no mode like that, a hybrid mode that keeps you stable at all times including take off and auto switches and flies the same between the two.
Also, I see no way in the APM to take off with GPS and land with GPS to have it auto shut off motors, only stabilize mode and that does not seem to lock on, unless I have not found it.