alex_markov
Well-Known Member
I can't say about before FW upgrade as I took my last Friday with FW coming and upgrading right away - But Yes it's really Very slow to acquire satts firs start - next flight on same location are alright 
Satellite lock after firmware update
- Thread starter NovelBuffalo
- Start date
BlairAir
Well-Known Member
Issues here. Directly after the update and continuing for 5 days. It seemed to help a bit by doing a Compass Calibration on location at a few places, but my understanding of GPS Aquisition would fit on the head of a pin. My philosophy was - it cannot hurt to do a compass calibration, so I went with that. While it seemed marginally better, today I git "poor gps signal" alert while airborne. I can only say that I've never experienced that with any DJI drone in my neighborhood. So there is obviously a sporadic issue affecting some users. This is more troubling than if everyone had it, since it might not get fixed as fast, perhaps.
JohnC
Well-Known Member
Decided to check again today as have not flown for a few days due to terrible weather in the UK.
Location England, UK, weather, cloudless sky, open farmland. 11C, 11:45 GMT.
Power up RCP, Power up drone, connection from RCP to drone took 15 seconds, 6 satellites by the time connection established & Fly App connected, 18 satellites at 55 seconds & Home point all recorded and ready to fly 60 seconds.
After a battery change, full lock and 20+ satellites within 15 seconds of drone power up x 2.
60 seconds for a cold start is OK and warm starts are OK too.
Its possible that the issues people are having may be down to a degraded service @ a specific location. Here in the North of England there is a very large electronic tactical warfare range, very popular range with the USAF etc, NOTAMs are quite often published when GPS jamming tests are being conducted.
Don't forget GPS is not a guaranteed service, even though we all use it.
Location England, UK, weather, cloudless sky, open farmland. 11C, 11:45 GMT.
Power up RCP, Power up drone, connection from RCP to drone took 15 seconds, 6 satellites by the time connection established & Fly App connected, 18 satellites at 55 seconds & Home point all recorded and ready to fly 60 seconds.
After a battery change, full lock and 20+ satellites within 15 seconds of drone power up x 2.
60 seconds for a cold start is OK and warm starts are OK too.
Its possible that the issues people are having may be down to a degraded service @ a specific location. Here in the North of England there is a very large electronic tactical warfare range, very popular range with the USAF etc, NOTAMs are quite often published when GPS jamming tests are being conducted.
Don't forget GPS is not a guaranteed service, even though we all use it.
JohnC
Well-Known Member
The GPS Signals that the drone uses are visualised with the GPS Icon on the display, a number of satellites are displayed this number refers to the number that are being used to allow the drone to fix itself to a location on the planet. The bigger the number the more satellites being used, this number fluctuates as satellites move out of sight of the receiver and new ones appear.
The GPS receiver performs a 'Cold' start if its been a while since it was last powered up, it will then update the 'almanac' in the receiver, basically a list of which satellites should be in view and when. Based on the ID of the satellite the receiver picks up the almanac from gives it a clue as the the ID of the ones it should be able to see. Once it sees a number of these it then can calculate its distance from each satellite based on a timing signal from the satellites. It knows where the satellite is in orbit so can extrapolate its location to the satellite, It then can calculate where it is in relation to a number of them and pin point its position on the globe and it can also obtain height information, although this is not used by the drone, it uses barometric pressure to get a relative height based on where it took off from, a reduction of 1mb (MillBar) is a height increase of approx 30'.
A 'Warm' start the GPS receiver knows which satellites will be in view based on its recent almanac download, so it will acquire a lock faster as it will discard satellites it knows will be too far away to get an accurate time signal from, hence it locks faster as its not having to do as much work.
There are a number of GPS swarms in orbit. operated by various governments, Navstar GPS (USA), GLONASS(USSR), Galileo(EU) & more recently BeiDou (China) until recently DJI was using GPS & GLONASS together but with the M3 has switched to GPS & BeiDou, the BeiDou system finishing deployment in 2020, there is probably a political need for a Chinese company to favour the Chinese system over the Russian one. It may also be a reason why some locations are having extended acquisition times!
GPS is a receive only service, nothing is sent back to the swarm from the drone!
GtoJon
Well-Known Member
JustFlyMore
New Member
Definitely really slow since firmware update.
Before tge update, by the time I was situated to take off I’d get a home point message. Now I waiting a good while for it.
I let it sit 10 min to get a really good lock of 18 Sats. Shut it down. Brought to same spot 2 days later and it took a while to get a good lock.
It’s like the GPS assist it broken. Which it gets Sat data from the web. This will slow GPS locks down a lot.
Before tge update, by the time I was situated to take off I’d get a home point message. Now I waiting a good while for it.
I let it sit 10 min to get a really good lock of 18 Sats. Shut it down. Brought to same spot 2 days later and it took a while to get a good lock.
It’s like the GPS assist it broken. Which it gets Sat data from the web. This will slow GPS locks down a lot.
alex_markov
Well-Known Member
It's not only slow but I have several warning midflight that sats are not enough and there will be altitude restriction 
might be for some reason it uses only GPS sats but not glonas baidu etc.?
might be for some reason it uses only GPS sats but not glonas baidu etc.?While letting it sit. I saw it get 12 Sats for home position, then drop to 10-11 (considered weak GPS). Once it got up to 18 or so (which took a long time) it would sometimes drop back to as low as 15 but never lower. Some of this behavior is all normal but everything is in slow motion with this update.It's not only slow but I have several warning midflight that sats are not enough and there will be altitude restriction
I may ground it until this is fixed. But if I do fly I’d wait untill I see 4 Sats above home position. E.g. 16 or so. Then maybe reset the home point again.
JohnC
Well-Known Member
It’s spec says it uses GPS, Galileo & BaiDou. Which is the only, published, difference between it and M2P, which is using GPS, Galileo & GLONASS.It's not only slow but I have several warning midflight that sats are not enough and there will be altitude restriction
A change between the V1.0 & the V1.2 of the manual does not list any changes in the GNSS being used.
Last edited:
smfry60
Well-Known Member
smfry60
Well-Known Member
Again today. 5minutes for Mavic 3 to get GPS lock, pull out Air 2 get GPS and lift off. MAV 3 still waitingI've been having some problems getting GPS satellite s too.. 5 minutes this morning then took off only to be caped at about 9 feet. My Air 2 does not have this problem.. before this update I don't remember having this problem..
BlairAir
Well-Known Member
Whatever the technical reason, it's unacceptable. For am issue this prevalent, there should be a single issue patch sent out immediately. Nit sure why they can't revert to Whatever was in place prior to FW V01.00.0400 - of course it's easy for me as an end user to say "it's simple! Just do x" - a ridiculous statement to make with zero knowledge of root cause. Any fool could see they should just do y" - and soon please.
I agree. I rather have the prior firmware at this point. Hopefully they will soon. Developers never like going backwards and always prefer fix it. It can get complicated, especially after a significant update because of common data migration issues. Updates often include data migration. And the old firmware won’t know how to read the new data. Migrating data backwards (which needs testing), only to eventually go forward later is costly and a lot of wasted effort if they know what the problem is and could just fix it.
But your right, they should drop everything and focus on a hot fix.
Same problem here. Compared to my other drones, The Mav 3 takes 4 times as long. I actually have to wait so long that 2 percent of the flight battery is gone by the time I take off with a home point established. I launch from a wooden 3rd story balcony. At this height with no obstructions, i would think the drone would get a full gps signal quicker than on the ground. I had this problem since purchase regardless of firmware updates.
I often wait to 98--96 % battery before full gps lock. No change since initial purchase or firmware updates. To get the signal quicker, I often launch to 100ft and wait for a lock.
bkushner
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