Slow GPS lock - is it Firmware or Satellite Constellations

[Dougcjohn]

Edit - found excellent thread on subject after creating mine.
Much good info & discussion... check it out!
Thread 'The BIG GNSS (GPS) Issue -- The Constructive Thread' The BIG GNSS (GPS) Issue -- The Constructive Thread

Regarding the SLOW GPS lock.
Not a expert on GPS, just read into the issues a bit to help understand why such a long delay to lock GPS.

From my rather limited understanding it's not a Mavic 3 FW related correction, but more of a satellite constellation group decision. In past DJI models (and other brands) have included the GLONASS and Galileo constellations as primary, along with the GPS GNSS constellation for a long time. The GLONASS system was removed from the Mavic 3 Firmware and substituted with the BeiDou constellation.

The GLONASS is a Russian Satellite system, Galileo is EU, and the BeiDuo is a Chinese satellite system... along with the GPS USA system. In the long scheme, the BeiDuo is suppose be much more accurate for aircraft under altitude 2,000Km and able to see 50% more satellites compared to other GPS systems.

The Craft's Firmware programming and the embedded circuits determine what satellite systems to examine & accept. Currently the long delay is the BeiDui Satellite system taking a much longer time communicating.

This may be associated to the BeiDou Constellation design... GPS, GLONASS, Galileo are basically "beacons" pickup by GPS GNSS Devices. The BeiDuo is a 2-way communication system, providing the ability to also transmit back to the Satilites: text msg, and various low level communications.

On the Mavic 3, my assumption is the quick 4-6 Satilites are likely GPS system, the extended time to obtain the remaining 6 satellites are likely BeiDuo system.

If that's accurate assumption, then a more efficient BeiDuo communication protocol would be needed to be programmed or the need to utilize GLONASS again to speed up the GPS lock. Until this is addressed, Mavic 3 will take time to lock onto 12+ Satilites.

A few interesting articles:

China’s Rival to GPS Navigation Carries Big Risks

BeiDou satellite network was completed this month

www.voanews.com

China’s BeiDou system ‘more visible from space than US rival GPS’

Researchers say a spacecraft travelling at or below an altitude of 2,000km would be able to see 50 per cent more Chinese satellites at any given time.

www.scmp.com

Is China's BeiDou a Better Version of GPS and GLONASS?

Here, we compare the world's major navigation satellite systems.

equalocean.com

What's The Differences Between the 5 GNSS Constellations?

Learn the differences between the 5 GNSS constellations including GPS, QZSS, BEIDOU, GALILEO, and GLONASS. Also the difference between GPS and GNSS...

blog.bliley.com

 

[GadgetGuy]

How does this explain the same delay when using the RC-Pro, which still uses the original GLONASS, instead of BeiDou?

 

[Meta4]

The Craft's Firmware programming and the embedded circuits determine what satellite systems to examine & accept. Currently the long delay is the BeiDui Satellite system taking a much longer time communicating.

Where does this idea come from?

On the Mavic 3, my assumption is the quick 4-6 Satilites are likely GPS system, the extended time to obtain the remaining 6 satellites are likely BeiDuo system.

If that's accurate assumption, then a more efficient BeiDuo communication protocol would be needed to be programmed or the need to utilize GLONASS again to speed up the GPS lock. Until this is addressed, Mavic 3 will take time to lock onto 12+ Satilites.

Too many assumptions and not enough facts.
You are ignoring that the M3 had no problem getting GPS in a normal time before that firmware update.

Even if the M3 couldn't pick up a single Beidou satellite, it still has plenty of GPS and Galileo sats to work with.
But the issue isn't so much slow GPS acquisition as that the M3 picks up a much smaller number of sats than would be expected for a receiver that has access to three different sat constellations.

 

[umanbean]

I doubt the problem is satellite consolation, more likely FW solace....

 

[Dougcjohn]

Where does this idea come from?




Too many assumptions and not enough facts.
You are ignoring that the M3 had no problem getting GPS in a normal time before that firmware update.

Even if the M3 couldn't pick up a single Beidou satellite, it still has plenty of GPS and Galileo sats to work with.
But the issue isn't so much slow GPS acquisition as that the M3 picks up a much smaller number of sats than would be expected for a receiver that has access to three different sat constellations.

Actually not accurate... I had 2 M3 Cine... The first was extremely slow, and before the GPS was discussed much. I returned it thinking it has issues. The 2nd M3 Cine has also been slow since new.

I personally haven't noticed any decline in speed to lock GPS from New through 2 FW updates. (It continues to be extremely slow as new).

I'll go with Satilite consolations and FW for GNSS, after 2 FW updates no improvements or change in behavior.

 

[Meta4]

Actually not accurate... I had 2 M3 Cine... The first was extremely slow, and before the GPS was discussed much. I returned it thinking it has issues. The 2nd M3 Cine has also been slow since new.

I personally haven't noticed any decline in speed to lock GPS from New through 2 FW updates.

I'll go with Satilite consolations and FW for GNSS, after 2 FW updates no improvements or change in behavior.

It's constellation, not consolation.

Now all you have to do is explain how yours works just fine but most don't.
They are all listening to the same satellite constellations.

 

[Dougcjohn]

Too many assumptions and not enough facts.
You are ignoring that the M3 had no problem getting GPS in a normal time before that firmware update.

Even if the M3 couldn't pick up a single Beidou satellite, it still has plenty of GPS and Galileo sats to work with.
But the issue isn't so much slow GPS acquisition as that the M3 picks up a much smaller number of sats than would be expected for a receiver that has access to three different sat constellations.

What hasn't been assumptions since initial launch... is there "fact" sited anywhere on the problem. All I've basically seen are YouTubes & Posts indicating a problem.

Until DJI states, reconizes and discusses the problem... it's all assumptions.

Hitting same point on wall with same assumed cause & correction isn't making it fact and not correcting.

As fast as DJI reacts on some issues... the DH Cert hack had an Ultra short reaction to block & correct. If this was a quick FW patch, it'd be addressed.

As stated at top of post, I'm no GPS expert... but I am entertaining possibilities.

 

[Dougcjohn]

It's constellation, not consolation.

Now all you have to do is explain how yours works just fine but most don't.
They are all listening to the same satellite constellations.

Sorry for phone autocorrect... that's not the issue.
If you notice in 1st post it's spelled correctly... your point?

Also, where did your eyes read my problem is resolved.

 

[Meta4]

Sorry for phone autocorrect... that's not the issue.
If you notice in 1st post it's spelled correctly... your point?

Also, where did your eyes read my problem is resolved.

Sorry ... my mistake .. reading too quickly.

 

[Meta4]

Until DJI states, reconizes and discusses the problem... it's all assumptions.

DJI have never worked that way, and probably won't with this.

But the fact remains, the drone has access to three different satellite systems.
Even if it never picked up a Beidou satellite, it still would be picking up more than enough of GPS and Galileo sats ... but it's not.

 

[BlairAir]

It's constellation, not consolation.

Now all you have to do is explain how yours works just fine but most don't.
They are all listening to the same satellite constellations.

Thank you. I was so annoyed that the OP said it and others repeated it. I had a crappy Fimi X8 Mini that used the Beidou constellation and achieved 12-15 locks in about 45-60 seconds.

Also, where on earth did someone get the idea that RC Pro uses Glonass? The aircraft locks on satellites - not the controller.

 

[Dougcjohn]

DJI have never worked that way, and probably won't with this.

But the fact remains, the drone has access to three different satellite systems.
Even if it never picked up a Beidou satellite, it still would be picking up more than enough of GPS and Galileo sats ... but it's not.

You may be correct... I personally don't know... my opinion still assumptions.

I disagree on DJI reaction to problems. They've reacted promptly to multiple issues over the years. Some quickly addressed, some included in a patch set. Some quick reactions created other negative issues... TB50 battery.

I gave 1 recent example... DroneHack certificate hack was reacted to very promptly... with FW version solely blocking DH Cert... no other issue.

They provide FW updates mainly to address or correct identified problems, 2nd is feature enhancements.

 

[Meta4]

I disagree on DJI reaction to problems. They've reacted promptly to multiple issues over the years. Some quickly addressed, some included in a patch set. Some quick reactions created other negative issues... TB50 battery.

DJI might fix things, but they never state, reconize or discuss the problem.

 

[Dougcjohn]

Thank you. I was so annoyed that the OP said it and others repeated it. I had a crappy Fimi X8 Mini that used the Beidou constellation and achieved 12-15 locks in about 45-60 seconds.

Also, where on earth did someone get the idea that RC Pro uses Glonass? The aircraft locks on satellites - not the controller.

The OP stated correctly and incorrectly... but let's find something.
I went back at looked.... 1 was misspelled all others spelled correctly.
Although, I agree with your RC Pro comment.

 

[mobilehomer]

Actually, on the DJI forum, one of the admins stated this week that the engineers discovered the cause and will be releasing a firmware update to correct.

 

[Dougcjohn]

DJI might fix things, but they never state, reconize or discuss the problem.

Good grief... publicly or internally... I'm sure they follow a common path to Dx & correct within Engineering... maybe not openly public on all matters. They do state "normally" what update addresses.

 

[Dougcjohn]

Actually, on the DJI forum, one of the admins stated this week that the engineers discovered the cause and will be releasing a firmware update to correct.

Great to hear... any additional info... link to discussion?

 

[mobilehomer]

Thank you. I was so annoyed that the OP said it and others repeated it. I had a crappy Fimi X8 Mini that used the Beidou constellation and achieved 12-15 locks in about 45-60 seconds.

Also, where on earth did someone get the idea that RC Pro uses Glonass? The aircraft locks on satellites - not the controller.

Yes, the RC Pro ALSO has GPS and does use GLONASS. With a standard controller, the phone GPS is used. That is the controller location in the radar in the lower left.

 

[BlairAir]

Actually, on the DJI forum, one of the admins stated this week that the engineers discovered the cause and will be releasing a firmware update to correct.

I also noticed that the specs on every other model I checked so far (4) say:

• Satellite Systems​

• GPS+GLONASS

Where Mavic 3 says:

• GNSS​

• GPS + Galileo + BeiDou

One difference is lack of Glonass, but I would not expect that to be root cause here. Just a data point.

 

[BlairAir]

Yes, the RC Pro ALSO has GPS and does use GLONASS. With a standard controller, the phone GPS is used. That is the controller location in the radar in the lower left.

Fair enough, but it's not what's slow.