Satellite lock after firmware update

[Meta4]

When the drone and RC is on the previous firmware which is .400 the drone only needs 11 sats to register the home point but on the latest firmware needs 12 sats to register.

The number of sats is not what matters.
The flight controller isn't waiting for some fixed number of sats.
It could be 10 or 11 or 12 or even more.

The story about mobile data and using the phones A-GPS has been debunked here

FYI .. switching off mobile data and switching on Flight mode does not prevent the phone from receiving wifi and GPS sat data or sending data via cable.
It just stops the phone from using cell phone internet data and sending wifi data.

 

[Suren]

That could just be showing the same variability in sat acquisition time that all DJI drones and other GPS receivers do.

The number of sats is not what matters.
It could be 10 or 11 or 12 or even more.

FYI .. switching off mobile data and switching on Flight mode does not prevent the phone from receiving wifi and GPS sat data or sending data via cable.
It just stops the phone from using cell phone internet data and sending wifi data.

Thanks for the explanations Meta4. I I know that cellphones even when not connected to the internet still receives GPS data as when seen when using apple maps but do you think it actually transmits this data to the drone via the connection to the RC? I am having a hard time believing what Dji dishes out at the moment but if its true then!!

 

[Meta4]

Thanks for the explanations Meta4.

I deleted my first comment after rereading your question.

I know that cellphones even when not connected to the internet still receives GPS data as when seen when using apple maps but do you think it actually transmits this data to the drone via the connection to the RC? I am having a hard time believing what Dji dishes out at the moment but if its true then!!

The phone could still get GPS data if the skyview isn't blocked.
It can also get location data from your home wifi.
The app would pick up any location data from the phone and display it on the map.
But I'm not sure whether the drone uses that or not.

 

[mobilehomer]

It would be nice to have a data flow chart for data and gps data from controller/device and drone. This would tell just where the bottleneck is. But, I don't think DJI would let the general public be privvy to that!!!

 

[GadgetGuy]

After my FW refresh of both the RC-Pro and the aircraft through Assistant 2 (Consumer Drones Series), last night, I did 3 new tests of satellite acquisition times today. From home, where I had a quick warm boot last night after the FW refresh, I had a quick cold boot this morning, 6 hours later, taking 2 minutes. I then drove 10 miles to a new location 6 hours later with tall trees nearby, and it took 6 minutes to set the Home Point. I then immediately drove 10 miles back to home, and it set the Home Point indoors within 30 seconds.

To help me better interpret my results, I need two questions answered:

1. For how long after a successful Home Point acquisition will that prior acquisition be usable as a warm boot, at the same location? (2 hours?)
2. How far away in distance from prior successful Home Point acquisition will that prior successful acquisition be still usable as a warm boot, if still within the time frame of a usable prior acquisition at the same location? (10 miles within 2 hours?)

 

[GadgetGuy]

New data point: 8 hours after the last quick Home Point acquisition at home indoors within 30 seconds (after driving 10 miles from the prior Home Point acquisition that took 6 minutes) Home Point acquisition at home indoors just took almost 8 minutes! Upon reboot, it then took only 15 seconds to set the Home Point, but that is expected under an immediate warm boot in the same location. 8 hours is apparently too long even in the same location. 10 miles away within 2 hours appears to be fine!

 

[Suren]

New data point: 8 hours after the last quick Home Point acquisition at home indoors within 30 seconds (after driving 10 miles from the prior Home Point acquisition that took 6 minutes) Home Point acquisition at home indoors just took almost 8 minutes! Upon reboot, it then took only 15 seconds to set the Home Point, but that is expected under an immediate warm boot in the same location. 8 hours is apparently too long even in the same location. 10 miles away within 2 hours appears to be fine!

If you leave the battery out and wait and hour or so and try again that would be a cold boot. Well from my tests it was.

 

[GadgetGuy]

I deleted my first comment after rereading your question.

The phone could still get GPS data if the skyview isn't blocked.
It can also get location data from your home wifi.
The app would pick up any location data from the phone and display it on the map.
But I'm not sure whether the drone uses that or not.

It's pretty clear to me that the drone won't use that location data available from the tablet. If it did, no Home Point acquisitions at home, where home wifi is always readily available, would still be taking 8+ minutes! RC-Pro quickly acquires its position on the map in the Fly app with precision within 30 seconds, but the drone is still consistently taking well in excess of 5 minutes to acquire the Home Point on every cold boot from the same location at home, where on a warm boot, it takes under 30 seconds.

 

[RocketBrew]

After refreshing Aircraft and RC Pro Friday evening, had a quick restart Saturday morning. I believe I left the battery in.

Then drove about 15 miles away to a job, took about 5 minutes to lock. Subsequent reboots were fast.

Drove about 1 mile away to next job, with battery removed, about 5 minutes to lock, subsequent restarts were fast, as expected.

Drove back to first location, with battery removed, and it locked almost immediately!

I am sure it didn’t have any bearing on this, but both locations were within 1/4 mile of Class C airport, and cellular reception on both Verizon and AT&T devices was very bad (not the case at these sites previously).

If you leave the battery out and wait and hour or so and try again that would be a cold boot. Well from my tests it was.

 

[GadgetGuy]

After refreshing Aircraft and RC Pro Friday evening, had a quick restart Saturday morning. I believe I left the battery in.

Then drove about 15 miles away to a job, took about 5 minutes to lock. Subsequent reboots were fast.

Drove about 1 mile away to next job, with battery removed, about 5 minutes to lock, subsequent restarts were fast, as expected.

Drove back to first location, with battery removed, and it locked almost immediately!

I am sure it didn’t have any bearing on this, but both locations were within 1/4 mile of Class C airport, and cellular reception on both Verizon and AT&T devices was very bad (not the case at these sites previously).

Thanks for adding some data points. Whether the battery is removed or not should have no bearing at all, as long as it is off. The warm boot GPS memory after powering down the aircraft, does not use the aircraft battery at all. The data is stored in flash memory in the GPS device itself. In my case, the warm boot survived when moving 10 miles within 30 minutes. It appears there may also be some memory of the same location recorded earlier, even after moving to a new location and returning within a few hours.

 

[GadgetGuy]

If you leave the battery out and wait and hour or so and try again that would be a cold boot. Well from my tests it was.

The battery just needs to be off. It doesn't need to be removed, but in the typical scenario, it is swapped in between flights. However, if the first flight didn't exhaust the battery, a second flight on the same battery should behave the same as a newly swapped battery.

The main difference between a warm boot and cold boot is whether the Home Point is quickly acquired. In a cold boot, it must start all over, and retains no memory of the prior satellite acquisitions. In a warm boot, it acquires them quickly, based upon a prior cold boot in the same location on the prior flight, after a battery swap.

The key is determining what the parameters are that allow a warm boot to occur, without triggering the cold boot time of 5+ minutes. It is well established that an immediate battery swap after a cold boot in the same location does not require a new cold boot.

What is unclear is how long the warm boot survives at the original location after a cold boot. Two hours seems to be a minimum.

It is also unclear how far away one can move from the original cold boot location, within a warm boot survival time, without requiring a new cold boot. I managed 10 miles within 30 minutes.

 

[Suren]

The battery just needs to be off. It doesn't need to be removed, but in the typical scenario, it is swapped in between flights. However, if the first flight didn't exhaust the battery, a second flight on the same battery should behave the same as a newly swapped battery.

The main difference between a warm boot and cold boot is whether the Home Point is quickly acquired. In a cold boot, it must start all over, and retains no memory of the prior satellite acquisitions. In a warm boot, it acquires them quickly, based upon a prior cold boot in the same location on the prior flight, after a battery swap.

The key is determining what the parameters are that allow a warm boot to occur, without triggering the cold boot time of 5+ minutes. It is well established that an immediate battery swap after a cold boot in the same location does not require a new cold boot.

What is unclear is how long the warm boot survives at the original location after a cold boot. Two hours seems to be a minimum.

It is also unclear how far away one can move from the original cold boot location, within a warm boot survival time, without requiring a new cold boot. I managed 10 miles within 30 minutes.

So far with all my testing, it was done at my home, off my deck so I did not drive to other locations to test. In my tests I tested waiting an hour with battery off and then powering up and boot times was about 2/3 minutes, if I removed the battery and tested after an hour I ended up waiting 6 minutes plus to get a lock. I then decided to downgrade to the previous firmware and wait 2 hours after that and got a lock under 2 minutes. Put the drone back to the latest firmware and waited 2 hours again and it took 6 minutes and 53 seconds or so. I went back to the previous firmware and am still there and I get a lock varying between 45 seconds to max 3 minutes which is more acceptable then before on the latest firmware. I have had a response from Dji on email asking for logs and screen recording again so need to wait but I believe that if more of us that complain and send in our logs and screen recording they will fix this and give us faster home point lock times.

 

[VenomXts]

this is getting BS levels I waited from a 100% battery to 92% to get ground lift off home point lock...

 

[GadgetGuy]

So far with all my testing, it was done at my home, off my deck so I did not drive to other locations to test. In my tests I tested waiting an hour with battery off and then powering up and boot times was about 2/3 minutes, if I removed the battery and tested after an hour I ended up waiting 6 minutes plus to get a lock. I then decided to downgrade to the previous firmware and wait 2 hours after that and got a lock under 2 minutes. Put the drone back to the latest firmware and waited 2 hours again and it took 6 minutes and 53 seconds or so. I went back to the previous firmware and am still there and I get a lock varying between 45 seconds to max 3 minutes which is more acceptable then before on the latest firmware. I have had a response from Dji on email asking for logs and screen recording again so need to wait but I believe that if more of us that complain and send in our logs and screen recording they will fix this and give us faster home point lock times.

There is no doubt in my mind that downgrading the FW fixes the cold boot lock times. I trust you on that completely. That is an important fact. It means it isn't a hardware issue. Unfortunately, it isn't a viable solution for those of us who have patiently been waiting for the Spherical Pano feature, which works beautifully, providing a 50-60MB high quality stitch in just 75 seconds from start to finish.

I am also confident that something can be done by DJI to improve the cold boot lock times in a future FW update. In the mean time, learning how to work around the problem is the best solution. Bringing along a spare battery for cold boot locks works best, and then simply swap batteries with a 100% remaining charge battery for flight.

If time is of the essence, it may be necessary to launch without a proper lock, which limits altitude to 96 feet. Flying straight up to 96' will give the best opportunity for quickly locating satellites. Once enough satellites have been located for a good lock, it will also then set a proper Home Point directly over the launch site, although the displayed height above the launch point will likely be roughly 100’ too low. Depending upon how long that lock takes at 96', one can either proceed immediately with the mission, or land and change batteries with a fresh 100% battery.

Since fully charged batteries auto-discharge to 96% within 72 hours, and cannot be topped off until they drop below 96%, to 95% or lower, I plan on using those 96% batteries for all cold boots, as the loss in charge from the cold boot of 1% to 5% will enable that battery to then finally be topped off to 100%, for a later flight with instant warm boot.

Any other suggestions in the interim for cold boot lock workarounds are welcome!

 

[GadgetGuy]

this is getting BS levels I waited from a 100% battery to 92% to get ground lift off home point lock...

Hopefully, you have more than one battery, so you can immediately swap out batteries, as soon as the HP is set, to fly with a 100% battery. The warm boot lock time after swapping batteries is almost instantaneous!

 

[Suren]

There is no doubt in my mind that downgrading the FW fixes the cold boot lock times. I trust you on that completely. That is an important fact. It means it isn't a hardware issue. Unfortunately, it isn't a viable solution for those of us who have patiently been waiting for the Spherical Pano feature, which works beautifully, providing a 50-60MB high quality stitch in just 75 seconds from start to finish.

I am also confident that something can be done by DJI to improve the cold boot lock times in a future FW update. In the mean time, learning how to work around the problem is the best solution. Bringing along a spare battery for cold boot locks works best, and then simply swap batteries with a 100% remaining charge battery for flight.

If time is of the essence, it may be necessary to launch without a proper lock, which limits altitude to 96 feet. Flying straight up to 96' will give the best opportunity for quickly locating satellites. Once enough satellites have been located for a good lock, it will also then set a proper Home Point directly over the launch site, although the displayed height above the launch point will likely be roughly 100’ too low. Depending upon how long that lock takes at 96', one can either proceed immediately with the mission, or land and change batteries with a fresh 100% battery.

Since fully charged batteries auto-discharge to 96% within 72 hours, and cannot be topped off until they drop below 96%, to 95% or lower, I plan on using those 96% batteries for all cold boots, as the loss in charge from the cold boot of 1% to 5% will enable that battery to then finally be topped off to 100%, for a later flight with instant warm boot.

Any other suggestions in the interim for cold boot lock workarounds are welcome!

That is a pretty good work around and given that most people buy the fly more combos we always have 2 spare batteries on site BUT we still need Dji to fix it. I agree that I should not have to be flying with the older firmware and it feels like I am only half of what I paid for but also Dji needs to wake up and they cannot make this so difficult for us. They just need to honour what they advertised and give us as close as possible to 46 minutes flight time, not wasting over 6 minutes of that sitting on the ground but good suggestion anyway.

 

[GadgetGuy]

That is a pretty good work around and given that most people buy the fly more combos we always have 2 spare batteries on site BUT we still need Dji to fix it. I agree that I should not have to be flying with the older firmware and it feels like I am only half of what I paid for but also Dji needs to wake up and they cannot make this so difficult for us. They just need to honour what they advertised and give us as close as possible to 46 minutes flight time, not wasting over 6 minutes of that sitting on the ground but good suggestion anyway.

I've always used the warm boot method on older aircraft, back in the day, when long distance flying with external batteries was a thing. However, those batteries could always be topped off to 100%, regardless of how close to 100% they were, and would not auto-discharge at all for 10 days. With any M3 battery charged prior to the last 24 hours, at best, it now starts at a 96% charge. If it then takes 6+ minutes for a proper lock and Home Point setting, most flights would begin with only a 90% charged battery, that then wants you back on the ground at no less than 15%, or the heart attack beeping starts, with a forced auto-land at 10%! That means only 75% is available for flight time! 100% to 0% is realistically around 35 minutes, not 46 minutes. 75% of 35 minutes is 26 minutes, only 3 minutes more than the Mavic 2!

DJI will eventually get the slow HP setting resolved. Until then, use the 96% batteries for satellite locking, so you can top them off to 100% after, and bring along at least one other 100% battery for flight!

 

[kesteloo]

We just received an official statement from DJI in which the drone maker acknowledges the DJI Mavic 3 GPS issue and promises us that it will be addressed with a firmware update soon. Read more about it here: DJI Mavic 3 GPS Issue - Fix With Firmware Update Coming Soon

 

[MS Coast]

We just received an official statement from DJI in which the drone maker acknowledges the DJI Mavic 3 GPS issue and promises us that it will be addressed with a firmware update soon. Read more about it here: DJI Mavic 3 GPS Issue - Fix With Firmware Update Coming Soon

Do you have a link to the DJI statement?

All I've seen is a partial screen capture and a second-hand copy of what's said to be text that someone received from DJI.

 

[kesteloo]

Do you have a link to the DJI statement?

All I've seen is a partial screen capture and a second-hand copy of what's said to be text that someone received from DJI.

It was emailed to us. I quoted the text from the email in the article.