So.........I Never Set My Home Point
- Thread starter Utopia Texas
- Start date
Ivan, I agree with most of what you say, but I have some comments on your post. But let me preface it by saying my comments are based on my understanding of the Phantom, which could be all wrong, partially wrong or completely correct. So if after reading this, please everyone, help me understand where I may be wrong. So here goes: I do believe the home point is saved as you say, but I don't think it is for good. That implies if I fly tomorrow and never get a lock, it will use the lock that was saved the day before. And that actually might happen, or it may not. The storing of this is done in volatile memory that is kept active through either capacitance discharge or a battery or both. I think there is a little battery on the GPS module that serves this purpose. So if you temporarily lose you GPS signal, it recovers your homepoint from memory. But given enough time, that GPS location is lost.
Concerning DHP. I think this is a terrific option. But I, and others, have had some issues that DJI has not addressed. In my case, the video screen flips back to the menu screen at random. One second I am watching the video from my craft, the next moment I am at the menu screen. I select the camera icon and I am back in business but not for long. It only happens when I select the DHP option. I also get an erroneous warning message indicating I do not have enough power to fly home. Trouble is I will get that message with 50% battery life and 10 feet from my landing area. Again, it only happens when I select DHP.
Concerning DHP. I think this is a terrific option. But I, and others, have had some issues that DJI has not addressed. In my case, the video screen flips back to the menu screen at random. One second I am watching the video from my craft, the next moment I am at the menu screen. I select the camera icon and I am back in business but not for long. It only happens when I select the DHP option. I also get an erroneous warning message indicating I do not have enough power to fly home. Trouble is I will get that message with 50% battery life and 10 feet from my landing area. Again, it only happens when I select DHP.
When I said for good/permanently I meant only for current session(until you turn off the phantom). So sorry if I was unclear about that.Mopar Bob said:
i never heard of batteries in GPS modules, I never also dissasembled a phantom GPS module. But I would bet there is no battery. Besides even if it was, the GPS module has nothing to do with actually remembering the home point position. Phantom has few onboard electronics. Computer(NAZA-M v2), WiFi access point, camera and GPS receiver.(I deliberately used more common names from home/PC electronics).
The computer(main controller or naza or how ever you are going to call it) is the one who remembers the home point among everything else it does. And it is powered by the main phantom battery. There is no auxiliary power supply inside(I wish there was). When the computer sees there are enough satellites it will report back over WiFi network to your app that the position is now accurate enough to consider it for a home point(blue H circle will appear in the ground station part of the app), it will also rapidly flash green with the rear LED lights on the phantom to signal the same. Now if you take your phantom in your hands and walk around you will actually see that the little blue H circle in the ground station is also moving around. Meaning it has not been yet finally saved as a fixed/definite home point. Once you start the engines and lift off, the blue H does not wander around anymore. Which means at that point the phantom computer has saved in its internal memory two floating point numbers, actually three: latitude, longitude and altitude. If at any point during flight the signal from your remote is lost the computer will fly back to those saved numbers. When you turn off your phantom the numbers are lost for good.
If it causes the problems you describe it is certainly DJI's fault and they need to fix it. I suppose it is happening on Android devices?Mopar Bob said:
I am 95% sure there is a battery there. Tiny little sucker I noticed when I replaced the antenna. I didn't really take a close-up look at it which accounts for my missing 5%. And yes, its the android app on a Samsung galaxy s4. Everything runs fine as long as I do not select DHP. I sent the error to DJI support and they paid little or no attention to it. They just sent a survey on how well they did resolving my issue. You can probably guess how I responded.
Mopar Bob I apologize and stand corrected!!! I just started googling around, and batteries inside GPS modules are actually a common thing. They are used so that the GPS receiver can memorize the so known GPS satellites almanac(information about visible satellites) so that it does not have to receive(download) that information from the satellites every time it is powered up. Without the battery it would take a much longer time to get the first fix everytime(up to 15 mins).Mopar Bob said:
However that still has no effect on the accuracy of reported position and certainly not on remembering the home point.
OK, so just for future reference, if one finds that its taking a long time to establish homelink, it may be caused by that particular battery going bad.
Quite possibly, but I would expect that it can last for years. At least 5, probably more...Mopar Bob said:
Bob I noticed what i thought to be a removal battery as well (all though pretty firmly in place) wonder how long she lasts for... If I took it to a watch fixing type guy..... he could probs tell me how many volts it is.. then I could take it out and check the voltage yeah ??
I don't have any issues... just interested is all..
I don't have any issues... just interested is all..
Not correct. But you will learn that on your own.Ivan said:
Happy flying.
slothead said:
Just curious Tom, but what part of the above do you think is not correct?
I guess technically you could take off with >= 6 sats right before the rapid greens, which tend to come within about 5 seconds of getting the >= 6 sats. Is that the part you think is incorrect?
You are close Black, but let me be more specific. I don't think I have EVER gotten the fast flash on the ground before getting up in the air. I try to climb to about 10 ft and hover waiting for the fast flash, but very seldom do I get it there with as many as 10 sats, so I just get tired of it and take off to wherever I was planning to go. And by the way, I disagree with your estimate of getting fast flash in about 5 seconds of having 6 sats - at least not in my neck of the woods. But I also think we are wasting bandwidth on this and I don't want to discuss it further.BlackTracer said:
Take care,
slothead said:
Great attitude, probably from so much flying in ATTItude mode.
Why did you even join the discussion in the first place?!
Back on topic:
If you are in "Phantom" mode you have slow flashing yellow lights untill you get 6 satellites. Phantom manual says slow flashing yellow is non-GPS(ATTI).
If you are in "NAZA" mode then you have one green flash followed by up to three red flashes signalizing how many GPS sattelites are visible.
3 reds = less than 5 sats
2 reds = 5 sats
1 red = 6 sats
0 red = 7 or more sats
The whole NAZA manual is full of references that say that any functionality related to GPS (like Home Point Recording, Home Lock mode, position hold) will not work while you still have 2 flashing reds. And you can also swipe to Ground Station part in the app at any moment while you still don't have 6 sattelites. In the upper left corner you are going to see in what mode you are and it will say: ATTI
Regarding the rapid flashing green lights and home point here is another part of the manual:
Everyhing is there. So everything I said is very consistent with the manual.
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BlackTracer said:
After a few hundred flights, my flight sequence evolved
My checklist reversed.I do what slot head does all the time.
I check surroundings and wind direction.
Take off in ATTI and fly around before the sats acquired.
I had foldable props so it was even quicker to launch.
Power Wifi extender + phone.
Power Phantom
Power transmitter
IOC = off, ATTI
Take off before the wifi has picked up in the DJI app.
I can then set new return to home point and return to height in mid flight.
Wait til wifi pick up on phone and hit record.
I then check the RADAR and see if home point is in reference and check GPS counts. It is here that I flick it to GPS.
I could not agree more with you Ivan. I have heard if you go back to the same place and fly you don't have to. Call me more careful than most, but I calibrate every-single-flight. I use a checklist and seems to be working fine. Lost a signal once (App crashed for some reason), didn't panic and when it said "Returning to home point location," I just let it come straight back and let it land right in front of me. Great talking point for your advice.
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