I was shooting some stills of a house under construction and had my first little scare. I was flying in mostly GPS hold as I was 100-200 feet up, viewing the monitor for framing the pictures. The copter did an abrupt change of direction away from me. I look down and it appeared the return to home switch was activated (not sure how long). I quickly went back to manual flight and all ended fine. Landed with no problems. Upon reviewing the summary for the flight log I see "ERR: GPS Lost" (21) occured 12 times!" The temps were warm that day so I don't know if that would have anything to do with the situation. You'll see my starting temps were around 90 degrees (80 degree air temps). These are probably the warmest temps I've encountered for MAX. I'm running a Canon SL1 with 40mm pancake lens so I think that's a reasonable load for CS6 (21 oz). If someone could review the GPX file and let me know what they can discover, that would be much appreciated. The flight BEFORE and AFTER had no compass errors and no GPS issues.
Here are the GPX files for the flights before and after the one above for reference. These two flights were 6200 mah batteries so you'll see the temps are a bit lower. The middle flight, where I had the GPS signal loss, I was using an 8000 mah pack (better for cooler days I suppose). Flight Before Flight After
Josh looking at your first file Come Home did not get turn on, at least from the log file. You did lose GPS lock. Doesn't look like there were any solar activities going on. Since it was transient it may be due to the position of the satellites to the horizon. If they are low to the horizon while you get 8-10 satellites the signal isn't as strong as when they are at a higher azimuth. Happend at 83 second mark and lasted 11 seconds. You recognized something was wrong and did switch off PH (not CH) going back to manual control.
Thanks Gary! I did not remember going into return home mode so that makes sense that it did not occur. The dramatic pitch that happened when it lost GPS resembled RTH characteristics (wrong direction in this case). It still seems strange how it could go from 8-9 satellites to 0. I can often get 4-6 satellites in my basement. Are the max temps still in the acceptable range for the ESC's?
You are starting to see the issue of flying in temps 80 and above. You are starting to get to the limits (100C). installing the small heatsinks on each of the BL's, top and bottom, will offer some help. Also slow hovering flight is the worst situation since you are not getting much airflow over the Bl's.
Very true Gary. I have noticed the parking method for photos is going to generate heat. Wish every work/flying day was 60 degrees outside. Fortunately most of the shoots I do are for video so i'm on the move in those situations.
Come to Oregon. Most of the days are 60F. Except in the summer. But that only lasts a few days and warm rain feels good. Andy.
Josh I have flown a lot in PH mode (as some on this board can contest to) and I have experienced the same exact reactions from the CS8 when you lose GPS lock. It's happened to me on golf courses and a few other places. When you lose GPS lock the copter does bug out for a second or two. It's very easy for one to lose enough satallites once you get in the air that it loses lock. There are many factors that contribute to it. Besides solar activity and sun spots, dense tree coveage can also affect your GPS strength. Large amounts of metal around your shooting location can also affect it, and wireless can affect it. What I do now is when I go to a new site and want to use GPS, I will look at the GPS satellite signal strength via MK tools. I will see how satellites are being picked up, what each signals strength is and how much they vary. This gives me a good idea of how reliable the signal will be during in flight. Even then though sometimes when you are in air things just happen that you can't test on the ground. This is why its good be prepared to react extremely quickly at the first sign of anything out of the ordinary and be ready to put in manual mode. There's just no way to prevent the sudden lose of a GPS signal but you can limit it to a certain extent by doing a site survey and a test through MK tools on site.
Personally, I use GPS lock for just a few seconds when I'm orienting the camera gimbal or checking something that'll require me to take my eyes off the copter (such as affixing my goggles or something). I am not a fan of "flying" with PH on, as the MikroKopter GPS hardware in our Cinestars is quite inexpensive consumer-grade stuff, and I've found it to be reasonably reliable *most* of the time. But IMHO those who rely on it constantly are going to feel The Beast's incisors in their backside eventually.