Suren
Well-Known Member
Honestly, I think what you are experiencing is just coincidence and has nothing to do with the app. Many of us on the Dji forum as well have not seen any change to GPS lock time after the app update.
The BIG GNSS (GPS) Issue -- The Constructive Thread
- Thread starter ianwood
- Start date
That may be true, but the questions I posed to you for DJI, and for you personally, are still very relevant. What RC are you using, and what device, on which platform?
It may be a very happy coincidence for me, but it was also fixed for me by the using the same procedure I followed before the update, which I still followed after the update!
Turn on the aircraft until 8 satellites are displayed. Takes 40 seconds for me. Turn the aircraft off, and then turn it back on. As soon as it reconnects to the RC-Pro, it will start out at the 8 or 9 satellites, find a 10th one, and immediately set the Home Point, and turn the satellite icon from yellow to white, all within 80 seconds of the original cold boot. Major game changer! It was taking 5-8 minutes previously on every cold boot!
The difference was that before the app update, by following the above "workaround" procedure, the satellite icon count at the time of the Home Point setting was still yellow, and now it is white, meaning a good lock, at 10 satellites or less, instead of 12+. That, in itself, is a huge change, after the 1.5.10 update to the RC-Pro!
It could be a mistake to assume that the icon changes to yellow or white based only on the number of satellites.
It's most likely relates to the GPS Health as assessed by the flight controller than the number of sats.
Suren
Well-Known Member
That may be true, but the questions I posed to you for DJI, and for you personally, are still very relevant. What RC are you using, and what device, on which platform? RC-N1 with IOS, iPhone 13 Pro Max
It may be a very happy coincidence for me, but it was also fixed for me by the using the same procedure I followed before the update, which I still followed after the update! - Because I am looking at all possibilities in hope of also getting faster GPS lock times, I tried your suggestion when I saw it in the forum this morning, before updating the app and it did not work.
The difference was that before the app update, by following the above "workaround" procedure, the satellite icon count at the time of the Home Point setting was yellow, and now it is white, meaning a good lock, at 10 satellites or less, instead of 12+. That, in itself, is a huge change after the update! - For my drone it is still waiting for 12 satellites before it locks homepoint.
Indeed, I completely agree with you. Based upon the color change from yellow to white, the Home Point setting is accurate. The GPS health is now being acquired significantly faster, and with fewer satellites counted in the app for me, using the RC-Pro and the above described procedure.
I doubt the number of sats is significant and it is always going to be variable.
The thing that stands out for me is that it's still getting <12 sats , when a receiver that has access to 3 different constellations should be readily finding something like 20.
See what I wrote yesterday here:
Napping with the Mavic 3 , Satellite Tricks.
@Phantomrain.org you keeping it? I need to make up my mind by the 31st was hoping to see the new firmware update come out today or Monday...
mavicpilots.com
We are also assuming that the app is accurately reporting the number of satellites in the app displayed number, instead of a numeric measure of the perceived GPS health. All I can really say is that I now have a Home Point set accurately close to me within 80 seconds, so I'm not waiting 5-10 minutes before I can take off with a set Home Point. That's progress to me!I doubt the number of sats is significant and it is always going to be variable.
The thing that stands out for me is that it's still getting <12 sats , when a receiver that has access to 3 different constellations should be readily finding something like 20.
See what I wrote yesterday here:
Napping with the Mavic 3 , Satellite Tricks.
@Phantomrain.org you keeping it? I need to make up my mind by the 31st was hoping to see the new firmware update come out today or Monday...
You can't any reply from DJI support seriously.
Sometimes ypu get replies from people who have no idea, sometimes you get replies that are just meant to fob you off.
Occasionally you might get accurate advice.
But you can't tell which when they give it to you.
This DJI response completely confirms everything that I have been speculating about, and announcing:
1. The 1.5.10 Fly app update was specifically intended to fix the GNSS issues
2. Those with the RC-N1 likely aren't complaining: it is fastest
3. Those with the RC-Pro will have better success while using Wifi/Hotspot
4. Using the RC-Pro off the grid will take the longest, likely up to 3 minutes
5. The update has completely fixed my cold boot GNSS issues with the RC-Pro with WiFi access. I'm getting a cold boot Home Point set in under 80 seconds with the reboot after 8 satellites are acquired, which takes 40 seconds. Without the reboot after 8 satellites, it is still under 2 minutes. The reboot at 8 satellites speeds up the Home Point setting process by almost 40 seconds.
What is there to change, that hasn't already been changed?
Suren
Well-Known Member
Dji mentioned in the Chinese forums and the English forums from senior admin there that there will be a firmware coming to fix the issue. There is a misconception that the new app fixed this issue which is not true. Like I mentioned it is coincidental that some have faster boot times and some don't. If the updated app fixed or was directed at the long gps wait times then why am I still waiting now more than 7 minutes? It was not focused on the wait times and that is a drone update that is needed not an app update.
Obviously, some speculation is necessary as DJI gives us so little to work with but let's try to distinguish what is pure speculation vs. what is observed vs. what is known/accepted.
(as well as what DJI support said which seemingly changes with the wind direction.)
FWIW, I too tested the new app version and also found a faster acquisition time than prior. About 2 minutes to the first home point (white icon) on a cold start (several days) and from 12 at takeoff to 19 after 30 seconds of flight. This is only an anecdotal observation though and until we see a consistent trend, we should avoid drawing conclusions.
And while we're on the subject of the new app, there aren't many ways a change in the app could change time to first home point. The one big one I can think of is AGPS but considering the RC Pro gets me up to 13 satellites within ~20 seconds, 2 minutes would still suggest the M3C is acquiring its GNSS data OTA.
(as well as what DJI support said which seemingly changes with the wind direction.)
FWIW, I too tested the new app version and also found a faster acquisition time than prior. About 2 minutes to the first home point (white icon) on a cold start (several days) and from 12 at takeoff to 19 after 30 seconds of flight. This is only an anecdotal observation though and until we see a consistent trend, we should avoid drawing conclusions.
And while we're on the subject of the new app, there aren't many ways a change in the app could change time to first home point. The one big one I can think of is AGPS but considering the RC Pro gets me up to 13 satellites within ~20 seconds, 2 minutes would still suggest the M3C is acquiring its GNSS data OTA.
You are assuming that displayed number is the total count of SVs the uBlox chip can see or is tracking. The main uBlox protocol message providing position solutions to client software (UBX-NAV-PVT) also provides a count of the number of SVs used in the navigation solution, which is a subset of the number it is tracking, which in itself is a subset of the number it sees. It depends on what DJI are choosing to display; the number from the NAV-PVT message (a count of the subset of tracked SVs used in the navigation solution) or the number of tracked SVs, which would be higher and have to be established from a different API message.
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Besides A-GNSS, of which there is zero evidence in the real world of this actually ever being implemented, there is one other area:
I feel the DJI Fly app is the custodian of the function of setting the home point for the drone, not the drone itself. You can change the home point mid-flight purely based on the map on the DJI Fly app for instance, and that updates the drone.
Despite what seems to persist in many viewpoints (that there is either a completely accurate fix or none at all), the reality is you get a 3D position fix from just 4 satellites. The who process of GNSS position calculation is for dealing with the fact that it is highly likely to be incorrect! I think the drones GNSS system sends the position calculation and parameters (xDOP, number of SVs in the solution, etc.) to the Fly app and it decides when to accept that, based on some programmed threshold. In that case, you could lower the acceptance threshold in the Fly app and "speed" up the process.
All this is building up more courage to open up the M3 and switch out the GNSS board if I can successfully connect to it. The truth isn't out there, it's in there
P.S. I implemented A-GNSS for a uBlox M8 and it was simple, just a few hours, utilizing uBloxs free AssistNow service - a simple HTTP GET request with a handful of params, it returns the data (~10Kb total for full ephemeris and almanac for every SV) in the format required to populate the UBX messages to send to the M8, so it's a trivial effort to download and then parse and upload to the chip - it can also be done on the fly while the chip is operating normally. For DJI, there'd be extra effort to send this over Ocusync and make it a robust implementation (failure recovery, loss or absence of internet, etc) but this seems like a relatively small effort for them vs. the marketing feature of an almost instant-on drone, if you have a network connection on the controller - it can be seen by user comments how valuable that would be. People claim to spend $1200 on the RC Pro just to save time to get the bird in the air......
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@beermat , I assume A-GNSS still requires an approximate location to be useful, no? I know mobile/cellular based A-GPS uses a crude triangulation of the nearest cell sites to establish a rough approximation of location for the mobile station.
Though I suppose that can be done with as few as 4 SVs too.
Though I suppose that can be done with as few as 4 SVs too.
You still haven't told us whether you are using the RC-N1 or the RC-Pro, and whether you have network access while booting up in your tests. Clearly, this is relevant, if you need further help!
Suren
Well-Known Member
I did, see my reply to you in the other post where you asked this question but anyways
I am using the RC-N1 with iPhone 13 Pro Max, I tried with mobile data on/off and wifi on/off and same results- drone sites on the ground for 6 minutes and 45 seconds or so (before app update) to get home point lock and now sits for over 7 minutes (after app update to get home point) I don't want to sound rude mate but at this stage Dji just needs to release a firmware update to the drone to fix the issues. There is not much anyone can do to resolve what most are experiencing with long GPS wait times, prior to the December update the drone used to lock GPS in 30 seconds or very slightly longer but it was very quick, after that update it started going downhill. I downgrade the firmware again yesterday to .400 and I get a full lock in 1 minute and 35 seconds so it proves firmware to be the culprit here.
My apologies, since I apparently missed your prior reply. However, your answer provides useful information that helps distinguish your problems from my own, and those of others that are now not having the problem. I am using the RC-Pro which is Android based. The RC-N1 with an iPhone is obviously using iOS. It could be that the 1.5.10 update successfully fixed the issue for RC-Pro users and Android users, but not iOS users. DJI has already stated they will fix the issue in the next FW update. There is also no doubt that the December FW update introduced the problem, but it the 1.5.10 Fly app update also apparently fixed it for some lucky users like myself. It should at least give you hope, until yours is fixed shortly, too! Try the reboot after 8 satellites are acquired, to see if that helps. It worked for me, even before the app update!
Suren
Well-Known Member
No issues mate. I did try your suggestion of turning the drone off when at 8 sats and back on and that did not help my case at all.
Wish I could help more. It's just a temporary situation, and it only affects the first flight, not any subsequent flights. Just bring along a fully charged battery to use for flight, and swap out the first battery, once it acquires the home point, and put the first one on the charger to top off, as it will be 95% or under, and be able to be fully topped off to 100%.
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