Lost mine today, RTH failed.
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Meta4
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The compass only helps resolve direction.
It has nothing to do with location.
Compass and GPS are completely separate sensors that provide data for the flight controller.
Wind speed also changes in respect to the obstacles it meets. trees for instance will slow it down, a rounded hill or a long ridge will speed it up, a series of hills or mountains depending on the distance between and wind speed may cause it to oscillate forming wave, wave clouds may form or may not depending on temperature and moisture content, very powerful things which even large commercial AC can have problems with, as glider pilots we love them, get on the down side and they can take you all the way down at quite a speed, so wind is not always horizontal.
Flying in mountains at all altitudes can present problems, a relaxing flight in what seems very safe conditions can change to horror when a corner is turned.
Point being, i see many scenarios where conditions would be much more than the phantoms performance and can change in a very short distance,
A guy could be flying his phantom at 2-300ft with very low wind speeds also having LOS, the moment the phantom goes shooting off in another direction at high speed and RTH does nothing, easy to assume something failed.
A guy could be flying his phantom at 2-300ft with very low wind speeds also having LOS, the moment the phantom goes shooting off in another direction at high speed and RTH does nothing, easy to assume something failed.
An excellent way to train RTH is to use the simulator. At first I could not figure out why the Drone had to be on and connected for the simulator to work, then I realized it is so it can properly read how the craft will react based on the firmware that is loaded.
Try this for example, load the sim, fly out 500 yards and turn off the transmitter. On the Simulator screen you will receive warning that signal is lost, and RTH has been initiated. You can allow it to come back and land. On another try monkey with the sticks after the RTH has started and see what happens. (hint fly away birdie) On another try turn the transmitter back on, and see if you can regain control. I have done all of these situations. And it reacts as expected.
One wish is that in the simulator there were a few buttons to simulate failure like drop GPS, drop connect to transmitter, etc.
If your drone loses GPS and an are flying line of sight which is a requirement for proper operation (not saying lots of us don't go beyond line of sight) then you can fly it home on ATTI mode. If GPS is regained drone can properly RTH. These devices have a wonderful number of failsafes, but they are not perfect, no product is.
Best advice is get a GPS tracker and attach it for fly away and landing out of visual sight.
I am using a dog tracker called whistle. Works great, weighs about an ounce and costs very little per month. Have the same device for my dog who is an escape artist, and it is fun finding her in minutes vs hours.
There seems to be a rash of "new" posters posting about topics they have no idea what they're talking about! You newbies would do well to listen to the seasoned forum members and moderators who have been here long enough to be proven to know what they are talking about on these new drones you have just gotten. Just a word to the wise.
I hope you are not referring to my post, it is very grounded in strong advice. My lack of posts does not show how long I have been in the hobby, just how long it took me to accept that it was cheaper to buy prebuilt. Going from scratch built to RTF is a tough pill to swallow, especially after 25 years in the hobby. I was flying quads 15 years ago built with pager motors and repurposed cell phone batteries.
I was referring to no one's post. Just a bit of general advice for the masses. I'm sure there are many of our new members who know their stuff.
My bad, you are right there have been some oddball responses in this thread.
Regarding the compass questions posed in drones..... I realize it's needed, but nobody has provided a rational reason why a Phantom can't work like a Garmin handheld GPS device. Any little error and the craft is totally lame to find a couple of GPS coordinates (Home Point)? I have a Garmin handheld GPS unit I use in the desert and it never requires calibration. It's calibrated at the factory and I have never had recalibrate. I am puzzled how the Garmin can be accurate across the country, but it's always better than 25' accurate with 8+ satellites. So why are drone compasses so sensitive that with a 100mi movement they have to be recalibrated? I know logically calibrating every 100mi east or west would be more accurate, but even if it's off a couple degrees it should still be able to find a couple GPS coordinates, I would think. How does Garmin get around this? Is it because of their "automatic calibration"? Why can't DJI do the same? Our Phantom chooses to go whacky with the least little magnetic disturbance. I've never had a magnetic disturbance with my Garmin, has anyone else?
Here's the Garmin instructions to calibrate. The wording implies it won't need calibration, given their "automatic calibration" feature. And for me that's been true.
Calibrating the Compass
Your device was already calibrated at the factory, and the device uses automatic calibration by default. If you experience irregular compass behavior, for example, after moving long distances or after extreme temperature changes, you can manually calibrate the compass.
NOTICE! Calibrate the electronic compass outdoors. To improve heading accuracy, do not stand near objects that influence magnetic fields, such as vehicles, buildings, and overhead power lines.
Here's the Garmin instructions to calibrate. The wording implies it won't need calibration, given their "automatic calibration" feature. And for me that's been true.
Calibrating the Compass
Your device was already calibrated at the factory, and the device uses automatic calibration by default. If you experience irregular compass behavior, for example, after moving long distances or after extreme temperature changes, you can manually calibrate the compass.
NOTICE! Calibrate the electronic compass outdoors. To improve heading accuracy, do not stand near objects that influence magnetic fields, such as vehicles, buildings, and overhead power lines.
- Hold UP.
- Select Settings > Sensors > Compass > Calibrate > Start.
- Follow the on-screen instructions.
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Not to throw a wrench into thread, but it also a good thing to always have a visual on your P3. I know **** may come up that RTH is your Ace in the Hole, but, like others folks have said would have to know a lot more about what really happend.
Today I had a similar event to the OP, multiple compass calibrations needed, however no catastrophe. I had flown the last three days, Fri, Sat and Sun with no problems near my home. I've never had to calibrate since I loaded 1.6, it's been working fine, as expected. Today I go to the beach (12mi east), didn't need to recalibrate, I flew two batteries, no problems. Third flight was a different story. Before launch everything looked great, MOD was around 1475 range, like the previous 2 flights. I got a green confirmation safe to fly, 12 satellites, all is good, battery was just charged 100%. So I take off and as I get about 150' away I have a RED warning of compass error. The craft automatically goes into ATTI mode, I could tell from the way it was flying. So I bring it back and carefully land it, fortunately there was no wind. This is the first time I've ever had a compass error mid-flight in the 6 months I've been flying this Phantom on previous firmware. So I do the compass dance and the craft LED lights confirm the calibration was completed successfully. However the RC still has the red compass error. Hmm. So I initiate another calibration and hold the drone a little higher, about 6', and do the dance. Again, the craft's LED lights confirm the calibration was completed successfully. And again, the RC did not go green, safe to fly. Puzzled, I flicked the mode switch from P to ATTI, then back to P. That produces the green light safe to fly, so I thought I was good to go, but then it goes red with compass error again 10 seconds later. Then another 10 seconds later all by itself it goes back to green "safe to fly" and stays green. So I launch and hover for 30 seconds to make sure all is OK, and the flight went well as normal.
This is the ONLY time I've ever had to calibrate more than once, similar to the OP. The 1st calibration was 5' above blacktop, on an old road with no metal nearby anywhere. Keep in mind I had just launched from this same spot 45 min earlier, no problem. Pretty strange behavior, but it all worked out. The only reason I went through the time to report this is because these were two "firsts" for me. 1. Getting an error after launch. 2. Having to calibrate twice in what I would consider an open benign area for calibration. Oh yeah, my phone wasn't on me. I'm not blaming 1.6, I just find it curious because this has never happened before, then, a few days after loading 1.6 I get this surprise. Have any others had this occur all of a sudden with 1.6? I'm not sure if the OP had 1.6 or not, I don't think he disclosed that.
So, now I'm thinking that if a mid-flight compass error occurs like this, after landing, it's likely wise to turn everything off, and then back on to start a clean compass calibration. That's what I should have done, and was going to do, but when it stayed green after the second calibration for a minute, then continued green in the air, I figured it was good to go, same as the OP, but his story ends much different. Which makes me wonder, if the OP got a bad calibration from all the rebar nearby (that's what we think happened, right?), why didn't it give him a compass error after he left the parking structure?
Fortunately I completed my beach mission with no surprises. It was awesome today at San Onofre beach during the golden hour. Check this sunset.
This is the ONLY time I've ever had to calibrate more than once, similar to the OP. The 1st calibration was 5' above blacktop, on an old road with no metal nearby anywhere. Keep in mind I had just launched from this same spot 45 min earlier, no problem. Pretty strange behavior, but it all worked out. The only reason I went through the time to report this is because these were two "firsts" for me. 1. Getting an error after launch. 2. Having to calibrate twice in what I would consider an open benign area for calibration. Oh yeah, my phone wasn't on me. I'm not blaming 1.6, I just find it curious because this has never happened before, then, a few days after loading 1.6 I get this surprise. Have any others had this occur all of a sudden with 1.6? I'm not sure if the OP had 1.6 or not, I don't think he disclosed that.
So, now I'm thinking that if a mid-flight compass error occurs like this, after landing, it's likely wise to turn everything off, and then back on to start a clean compass calibration. That's what I should have done, and was going to do, but when it stayed green after the second calibration for a minute, then continued green in the air, I figured it was good to go, same as the OP, but his story ends much different. Which makes me wonder, if the OP got a bad calibration from all the rebar nearby (that's what we think happened, right?), why didn't it give him a compass error after he left the parking structure?
Fortunately I completed my beach mission with no surprises. It was awesome today at San Onofre beach during the golden hour. Check this sunset.
My eyesight is not all that good these days, which means I am only allowed to fly 1800 feet away, while my quad is perfectly capable of flying 5km away with 100% control, and I can see my Air 2's screen quite perfectly at 2 feet away? Really?
Even if you still have 20/20 eyesight, are you suggesting that by seeing your quad at 2000 feet you will be able to tell whether it has suddenly developed compass or GPS problems? You will instantly be able to tell if it is reacting properly to RTH instructions? You can tell at 2000 feet whether it is flying forwards or backwards?
I also fly a Blade 350 QX 2 with a GoPro 4. I should have stuck with that, eh?
sorry for the loss
many of those " informed " opinions may be telling you what you don't want to hear, but they are not wrong, sorry!
you are assuming things that may not be valid. you will learn if you stay flying.
as far as resources about dji stuff --you are here , if some one here cant help you got issues!!!!
most folks on here offering help did NOT start flying phantoms at Christmas.
Many have had multiple phantoms and still do , some flying for years etc.
what they can tell you and help you with is NOT in any book, this stuff evolves daily as we are still very early in the whole concept of what these do.
read and take it in you will do well.
all dji manual oar on the dji.com site
good luck and have fun flying!
Meta4
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To start with your last point - Yes, I have.
The electronic compass in a Garmin handheld is susceptible to magnetic influences just as the Phantom's compass is.
I use Garmins a lot for fieldwork and had a couple of incidents where the GPS wanted to take me on a big curve around my destination rather than take me right to it.
Once was on foot near high voltage powerlines and also in a Caterpillar backhoe where the compass was confused by the 10 tons of steel in the machine.
I avoid the GPS units with built in compasses now as a result of those educational experiences.
There are a few differences between Garmin GPS units and a Phantom 3.
One is that the Phantom is self propelled and another is that the Phantom has a lot of electronic components, motors (with magnets), live cables etc that have active electromagnetic fields which need to be compensated for to get an accurate compass reading.
I suspect that Phantom compass calibration is mostly or maybe totally related to this rather than distance and magnetic declination.
I travelled 430 miles and couldn't find a safe location for calibration and flew safely for a week.
On another trip I went 1300 miles and remembered to calibrate but forgot when I came home and the P3 flew perfectly.
You need to calibrate your compass so that it can fly straight.
Calibration allows your compass to compensate for the magnetic fields running around the Phantom itself.
Anyone recalibrating in a distorted magnetic environment near iron or steel like a truck, a manhole cover or on a concrete structure with steel reinforcing is engaging in risky behaviour that can result in losing your Phantom.
Not calibrating is safer than giving your Phantom a bad calibration.
Read Ian's excellent post on compass calibration to have a better understanding of what your compass is all about.
Compass Calibration, A Complete Primer | DJI Phantom Forum
Meta4
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Thanks Meta, good read. I didn't know about the asphalt part. I'm curious why that's problem when there's no rebar in it. I'm not arguing the point, this is just a new datapoint that surprises me. I have launched from asphalt countless times, never had a problem till today.
