Lately I've been watching some DJI Mini 3 Pro related videos and I found out that there is an interesting change in the technical specifications of the new drone. While the DJI Mini 2 still relies on GPS, GLONASS and GALILEO for the global navigation satellite system, the following compilation can be found in the specifications of the DJI Mini 3 Pro: GPS, BEIDOU and GALILEO.
Chapter in this post:
GPS and GNSS - what's the difference?
When we talk about GPS in everyday life, we actually mean GNSS, because devices such as smartphones usually use not only the American GPS system, but also other navigation satellite systems - such as GLONASS, BEIDOU or GALILEO.
The abbreviation GNSS in turn means "Global Navigation Satellite System" and that could be translated into German as "global navigation satellite system" - abbreviated "GNSS". So you can see that anyone who talks about devices with GPS support in everyday life actually means devices with GNSS support.
Switch because of the Ukraine war?
In terms of timing, one might think that this change in the multi-GNSS setup might be related to the Ukraine war that Russia started. That GLONASS-System is operated by the Russians and so there might be concerns that it will be in operation for a long time.
Personally, I would find that strange, because the DJI Mini 3 Pro has certainly been in development for a long time and an electronic system like a GNSS will certainly not be thrown overboard within 3 months.
Possible reasons for switching to BEIDOU?
DJI and BEIDOU have one thing in common: they are based in China. Accordingly, it was obvious for DJI to switch to the Chinese counterpart to GLONASS.
Another reason could also be the accuracy, which in such systems depends on the number of satellites that are in orbit. Here, with 35 satellites, BEIDOU has a clear lead over GLONASS, which still has 24 functioning satellites in operation.
But apparently a high number of satellites does not necessarily mean high accuracy. I have therefore selected the number of satellites and the accuracy of the systems for the article and put them together for you here. Most systems offer a free and a paid version, with the paid version naturally providing much more accurate values. In the consumer drones, however, only the free GNSS are used, so I limit myself to that.
Another aspect that gets lost in my table is vertical accuracy, because while some systems have high in-plane accuracy, determining heights is a different matter altogether. Here, for example, GLONASS has a higher accuracy than the American GPS in some areas. But GLONASS coverage is not as good worldwide as GPS.
| GNSS | Operators | number of satellites | Accuracy (horiz.) |
|---|---|---|---|
| GPS | USA | 24 | 7m |
| GLONASS | Russia | 24 | 5 - 7 m |
| GALILEO | Europe | 30 | 4m |
| Beidou | China | 35 | 10m |
You can see that replacing GLONASS with BEIDOU cannot actually be justified due to the accuracy. So I assume the decision was made by DJI to promote the Chinese GNSS alternative. But that is pure speculation. If you know more, please leave a comment.
High accuracy by combining several systems
It is interesting, however, that by combining GPS and GALILEO an accuracy of a few centimeters has already been achieved. The DJI Mini 3 Pro utilizes GPS, BEIDOU and GALILEO, and it becomes clear why DJI's drones are nailed in the air. Thanks to the GNSS, they simply have very precise positioning and thus maintain their position thanks to the extremely fast readjustment by controlling the motors.
A-GPS - more radio networks for better accuracy
The systems on the smartphone work with the Assisted Global Positioning System, or A-GPS for short, to further increase the location accuracy. In addition to the GNSS data, the method uses Bluetooth, WLAN, mobile data and the exact distance to mobile phone masts. With the additional information, an accurate and fast GPS fix is guaranteed - in some cases even when the visibility of the GPS satellites is limited.
I think it is impossible that these systems will also be used in the DJI drones, since the drone cannot evaluate mobile phone masts without a SIM card. If I'm wrong here, I'm happy about an improvement from you.
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Jens has been running the blog since 2012. He acts as Sir Apfelot for his readers and helps them with technical problems. In his spare time he rides electric unicycles, takes photos (preferably with the iPhone, of course), climbs around in the Hessian mountains or hikes with the family. His articles deal with Apple products, news from the world of drones or solutions to current bugs.
The problem with GLONASS is the error. Misdirection is a technique built into satellite navigation systems that can be turned on by the military. (Civilian) navigation devices are then completely or temporarily misguided. Deviations between 50 m and 5 km are generated artificially.
The military's own navigation systems have a decoding stage that can calculate this misdirection.
The USA also has the corresponding technology, which is why geocaching was not fun at times during the Iraq wars.
If Russia is constantly or repeatedly involved in wars that ensure that this misdirection is switched on more frequently, then that would be an unreliable technical partner for drones.
Hi Peter! Are these erroneous instructions then regionally limited or worldwide? Apparently more worldwide if geocaching in DE was affected by GPS. But yeah, that's a stupid thing. One more reason to give up these stupid wars.
I suspect that older satellite networks, which are based on a few satellites, cannot be converted as precisely as networks made up of a large number of satellites.
Incidentally, the Americans' wrong direction was switched on by default for many years, which is why early navigation systems often displayed the car 5 meters off the road. I still remember it very well, a suitcase-sized part under the passenger seat, in which 2 CDs were rotating. Only right/left instructions with no street names, no lane guidance, etc.
I think it was from Kenwood. When the data was no longer correct, Kenwood could no longer deliver the follow-up CD to which they were entitled. Instead I got a new sat nav. It was all on the radio then.