Flying my Solo this evening when it flew off and crashed across the street after my son took a picture of it while it was hovering in front of him. No warning - just went. Solo was completely unresponsive to control attempts. See the event here: https://youtu.be/m368_A9hIwQ
Uploaded log to 3DR. Really lucky no one was hurt as kids had just been watching. Second flight - battery was around 20% - getting a picture just before going to land it.
Broke 3 blades but no damage to Solo or GoPro.
Doesn't build confidence when it just decides to do its own thing...
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Also, with all those people trying to fly near to their houses where gps position fluctuates as it locks and looses sats causes drone to wander around - there will be crashes. Flying close to car frustrates compass - may be also a reason to crash. I am really curious how 3dr will be able to keep their promise to cover all those crashes.
Amen!!! Somebody finally brought up the conversation of redundant gps!! Commercial airliners use multiple GPS computers that "vote" amongst the 7 on board, the weakest one gets voted out until it regains sats....hmmm. And yes GloNass is the way to go. Seems to be working for..you know who!!! Im not supposed to say the DJI word..im in trouble on this site for that. Oh yah..Im not supposed to bring up the Inspire word either.
So are reports from others of it (Solo) using the uBLOX NEO-7M GPS wrong?
Many people are flying their other brand (DJI) copter near their houses and cars with no problems - the GLONASS seems to have added a lot to the mix. With 50-100K of their new P3 machines out there, we'd be hearing of a number of similar crashes if it didn't perform better than shown here.
I shudder also at the cost of all the repairs and replacements. It will eat into cash flow, that's for sure. But at the same time if it costs them $500 each to replace (OEM) and they replace 2,000 of them, that's only a million dollars. This would be a lot to the former 3DR, but is a tiny fraction of the venture money they have come into.
Still, a million here and a million there and eventually you are talking real money :-)
The bigger cost is possibly to their reputation as the launch doesn't look as advertised.
I think these are moot points when you have a decent gimbal - that is, no benefit to flying manual and most pilots would probably lose their machines if this were true.
I am testing out the P3 and it does usually have 13+ sats and has never lost the GPS connection - even next to buildings and in large forests, etc.
Not to say it's not possible, but all anecdotal evidence points to a vastly improved GPS lock.
3DR claims they made a decision that this was not so. That is, that GLONASS does not add anything to the mix. They will probably defend their decision, but it goes against a lot of research and reports.
"Dual-system receivers and antennas deliver a clear advantage for high-precision positioning in such applications. In fact, Taoglas’ real-world driving tests reveal quicker time to first fixes, with accuracy improving from meters to sub one meter."
Conclusion
The tests were stark in their results: GPS/GLONASS dual-system antennas definitively offer a noticeable improvement in accuracy and performance. Urban environments are the true test of performance, and dual-system antennas are clearly superior."
http://electronicdesign.com/test-amp-measurement/real-world-drive-t...
A common thread in recent fly-aways is the Solo is flown in close proximity to a structure of some kind. In one video a multi-level home is nearby; in another there's a boat house to the right and a large structure to the rear; in the ill-fated demo there's a food truck no less than 20 feet away.
Some have hypothesized that operating a camera in close proximity somehow accounts for fly-away, but I think a more likely explanation follows from the way Solo uses GPS. The Solo requires a strong GPS lock with no less than 6 and as many as 12 satellites in communication at one time. Accord to 3DR, the requirements defining the Solo's GPS lock are:
These are fairly stringent requirements and they're enforced by acquiring communications with a redundant number of satellites, i.e. no less than 6 and as many as 12. While I'm no expert I'm going to propose another explanation for this class of fly-away: multi-path errors caused by nearby objects. 3DR emphasizes and reiterates in several places that operators "always choose an open flying location with a clear view of the sky". In autopilot, the key word here is "open".
It's not enough to say 'fly-away caused lost GPS signal'. In autopilot mode the Solo won't take off without locking on to at least 6 satellites. To get the kind of resolution required the Solo must have an absolute minimum of 4 signals of sufficient strength at any given time. Since it requires a minimum of 6 to fly (and may have up to 12) it keeps (I'm guessing) at least 2 in reserve in the event that any one of the 4 is lost. So when we say "lost GPS signal" what's has to happen is that the Solo must lose anywhere from 3-8 signals simultaneously, depending on what number it initially acquired. It requires 4 to fly without error, won't take off without 6, and may have as many as 12.
On the other hand, in events where large objects are in proximity to the Solo during autopilot flight, it is a possibility that - instead of just suddenly losing all redundant satellite communications - one or more of those signals might get reflected off a nearby object. If that's the case we now have two signals: the original traveling directly from satellite to receiver and the reflected signal traveling indirectly to receiver. Given the common theme of having large objects in close proximity in recent cases of fly-away, I suggest multi-path errors might be a reason. Other (similar) explanations are poor satellite geometry, interference and radio signal obstruction.
Moral to the story: don't fly near a food truck!
It's not real science, but I took another brand of GPS quad outside today 10 feet from a 3 story house surrounded by very tall trees and on a slope headed uphill - not exactly open ground and house was in the way of a large part of the signal.
T-Storm was on the way so winds were gusting 15+ - model stayed almost perfectly still and in control. I flew it around for 10 minutes or so in these conditions.
So called "consumer quads" - and I use that term in quotes because we are not there yet - still should perform at the highest proven level as of mid-2015.
Multipath is something which all GPS devices deal with. Many pilots - especially those with at least some experience - have flown for years in areas such as this and there is a very low percentage of problems. I remember a vid from 2013 NAB with the current Chief Revenue Officer of 3DR (worked for DJI then) grabbing his quadcopter at their outdoor booth - hand launching it and flying it 100's of feet away over 100's of attendees an in an area of large convention center buildings. If it could do that easily 2+ years ago, it shouldn't be a problem these days (aside from the general warning about flying over people, etc.).
It would be good to know who the pilot was in order to access the claims about this event. With a 3DR shirt and a prototype machine, gimbal and controller in her hands, you'd have to think she was from 3DR and trained. Their engineering location is a few miles from this demo site and it was advertised that 3DR reps would be there.
All of your reasons are valid - but you didn't mention IMU or compass. A number of these events seemed to happen after a short flight - then the machine comes down to hover near the ground (or land), and then the event occurs.
They released a new update - I guess they have to wait a week or two now and we'll see if this improves or stops altogether. If so, it could have just been in the way the sw or fw reacts to normal events.
Way back a long time ago, I did software engineering work with GPS and avionics systems for corporate jets. We had to incorporate things like Kalman filters into our systems to prevent some of the same issues that Solo is encountering.
From the Kalman filter wiki page 'The Kalman filter uses a system's dynamics model (e.g., physical laws of motion), known control inputs to that system, and multiple sequential measurements (such as from sensors) to form an estimate of the system's varying quantities (its state) that is better than the estimate obtained by using any one measurement alone. As such, it is a common sensor fusion and data fusion algorithm.'
I suspect that the Solo code does not utilize any filters such as this.
And, Yes, this is a totally different issue than GPS lock.
"I suspect that the Solo code does not utilize any filters such as this."
This is an odd assertion to make considering it is openly and frequently advertised that the pixhawk uses an EKF for sensor fusion and state estimation.
http://copter.ardupilot.com/wiki/common-apm-navigation-extended-kal...
v3.3 and after, the EKF is the only option. Prior to that, EKF is optional as the "old" tried and true DCM complimentary filter is used by default. Both work very well, but the EKF "knows" when a sensor is getting sketchy and does it's best to work without it.
Hello Phillip,
Thank you for the response and information.
I'm taking stabs in the dark while I await 3dr to get back to me on the incident posted in http://diydrones.com/group/solo/forum/topics/pilot-erorr-solo-error
As an outside observer, here are my thoughts:
Good luck and I hope things work out well for you.
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