A history of DJI wireless system, is Walksnail using DJI technology? – sUAS News – The Business of Drones
Last week Joonas from fpv.wtf released some info on Twitter on what we believe is the origins of the DJI digital FPV system chipset known as the P1 and what Waslksnail may be using in the Avatar system and today I wanted to expand on that.
There has been a massive amount of conjecture and speculation over the Avatar system and if it is actually DJI, based on DJI chipset or just something similar. To understand this more we have to look at DJI first and the chipsets they have used over the years from Leadcore, Artosyn and others. Leadcore To start we first have to understand who and what Leadcore is, the company was a fabless chipset design house that was a subsidiary of Datang Telecom Technology Co., Ltd, who in themselves was a subsidiary of the partly Chinese state-owned “China Academy of Telecommunications Technology”.
Leadcore’s main business was the development of application processors and IP for mobile devices. In 2014 they were the sixth-largest supplier of smartphone SOC in China. Its LC1860 chipset was widely used in devices across China. Leadcore appears to have somewhat vanished in 2018 when its parent company Datang Telecom Technology was apparently having financial difficulties and faced being delisted from the Shanghai Stock Exchange.
However, their chipsets are still used today in many drones from Autel and their IP lives on in other chipsets. Artosyn Shanghai Kuxin Microelectronics Co.Ltd, known in China as Kuxin with the Artosyn brand is a Chinese fabless chip design house specialising on wireless video processing and AI chipsets. So back to DJI.
The best place to start is with the release of the Inspire 1 (I1) where DJI introduces Lightbridge. A new Wimax-based wireless system that replaced the basic WiFi-based systems they were using before and offered HD long range video and RC control link. It was originally driven by an Altera Cyclone V FPGA in the I1 and then Phantom 3 Advanced and Pro, then later in the Phantom 4. In later variants of these models such as the B, C remotes DJI replaced the FPGA with a pair of SDR chips from Artosyn, the AR8001 DSP and AR8003 RF transceiver.
The overall system was the same, simply the chipset it was running on changed. A little later with the release of the Inspire 2, DJI started using the Leadcore LC1860 chipset alongside the Artosyn AR8001 with an AD transceiver. In the Phantom 4 Pro DJI again was using Lightbridge 2 however this time the Artosyn AR8001 was gone and replaced with a very similar-looking chipset but with a DJI logo on it. It’s believed this was still the AR8001 or at least a variant and shows DJI was starting to ‘tinker’ with getting silicon with its own name or specific specs.
When DJI released the Mavic Pro it came with a new wireless system called Ocusync. Overall very similar to Lightbrige but the big technical change in this was that it was said to be an SDR. Whilst Lightbridge was also an SDR with the Artosyn chipsets under the hood changes were that the Artosyn chipsets were gone and the Leadcore LC1860C coupled with the IE1000 front end transceiver from Imagination took over the full job of the radio system.
At this point, it’s fair to summarize that DJI had been working on using the built-in SDR LTE modems and the ARM cores for driving the wireless system for some time on the Leadcore chipset alongside and felt it was now in a position to transition to that fully. DJI continued to use the LC1860C Leadcore chipsets as the SDR in all Ocusync and Ocusync 2 models from that point including in the Ocusync Air FPV system, the DJI White Goggles and Goggles RE. O2 that was released with the Mavic 2 was very much a code improvement over Ocusync in most respects and even offered some compatibility back and forth.
Quietly in the life span of the Mavic 2 DJI released a B remote with the enterprise edition, that in itself was nothing particularly unusual as we have seen in the past however there was a rather large hidden change and that was that DJI replaced the Leadcore LC1860C with a new and at the time unknown chipset.
This new IC seen in FCC filings has a Leadcore logo among others but looked different to everything before, however later we now know it looks a lot like what was to come next. This brings us somewhat up-to the present day and the DJI Digital FPV System.
With the release of this DJI introduced the P1 chipset. This new SOC was believed to be a custom DJI ASIC that allowed them to develop a lower latency system than we had seen from anyone before. As time has gone on and with a massive amount of work from the likes of tmbinc, bri3d and joonas we now know that the P1 is really just a customized and dedicated Leadcore IP based chipset with tweaks to the LTE baseband that go beyond just using the modems like in Ocusync 2.
It’s nothing specifically magical, it’s just more customized for this use case with the “bits” not needed for tablets and smartphones removed and deeper changes to the LTE baseband. We know it still has two big Cortex-A7 cores, some small ones, Ceva DSP’s and a few other bits.
They are basically using the same CPU core + DSP setup as the Leadcore chipset and it’s likely running custom software for their LTE-based OcuSync and this is what’s making the difference. The first A7 core on the P1 runs Linux, while the second runs the baseband RTOS in combination with dedicated DSPs. All later drone models from DJI including the M200 V2, M300, Mavic Air 2, Air 2S, Mini 2, and Mavic 3 all use the P1 chipset with their remotes using either the P1 or its smaller brother the S1. The P1 has become DJI’s core chipset for all their Ocusync systems now.
Leadcore Chipset In Autel and Herelink & Artosyn In Other Manufacturers Alongside DJI, it has been found that Autel has also been using the Leadcore chipsets in their drone wireless systems, even the Herelink Pinecone S1 SOC was co-developed by Leadcore and Xiaomi.
While others such as Autel use Leadcore, Zero Robotics and Hollyhand use Artosyn chipsets with similar functionally. It’s worth noting though that DJI has been largely a step ahead of everyone else and there is clear history and a relationship between DJI, Artosyn and Leadcore that seems to have given DJI the edge over everyone else. So what does this all mean?
From a high level, you can look at this as the Chinese state government tasked parts of its wireless industry to create rival chipsets to the likes of Qualcomm for the domestic smartphone market. This has allowed Chinese manufacturers like DJI to gain much deeper access to the LTE baseband modems used than we have seen in the US and EU and this has allowed them to develop the system we see today.
The question of who actually did the work is not known but it’s likely with the clear relationship between all the companies there has been a few hands in it to develop low latency wireless systems that leave the competition standing. Today we see chipsets from Artosyn such as the older AR8020 that appear to offer a lot of what DJI has in the P1, and the newer AR8211 has more functionality with H265 and 4K30 capabilities.
These are what you could call off-the-shelf silicon however getting access to these is far more complicated than ordering from Mouser or Digichip. They are very much kept out of the public’s hands. It’s very interesting how these Artosyn chipsets have developed in recent years especially since Leadcore as a company seems to have publicly vanished, it’s very likely that there is Leadcore DNA and IP in there. Did DJI rattle the US government?
A final and interesting point on DJI on this subject is around the rumours that were circling for some time that the release of the DJI FPV system coincides with the US commerce ban and there was talk that DJI was using a US-based chipset and the US GOV was not happy with what they had done and banned them. We now know that is largely incorrect however I will add that we have not seen anything like what DJI has done with the LTE baseband modems in the West and while it may not be a US chipset the original LTE core IP origins have links to Qualcomm and/or Ceva and it’s not at all beyond belief that what they have done rattled some cages in the US and EU where this kind of “tinkering” is largely reserved for the military.
So what about Walksnail and Fatshark Dominator HD. While we don’t know for sure the new Artosyn chipsets certainly fit the bill the AR8211 has more functionality than the DJI P1 with H265 and 4K30 capabilities. I would not be shocked to see this or a variant of it in this system. We know Artosyn is working with partners on FPV as they confirmed this to Joonas when he contacted them.
In the end, the simple reality is DJI is simply doing what they have always done and developed their system based on others’ tech and IP, that’s what DJI is best at. They may be doing some custom implementation in the modem but it’s nothing magical. It looks like Artosyn is doing the same and Avatar is using that. If this is all the case it’s not a copy or clone, it’s simply just a similar implementation based on the same underlying technology.
Final Notes. I want to say a massive thank you to
Joonas first of all for the help, info and support helping put this together, furthermore a huge amount of thanks to tmbinc and bri3d for all the amazing work they have done helping us unravel this all.
Joonas Twitter https://twitter.com/fpv_wtf?s=20&t=q9...
fpv.wtf Website https://fpv.wtf/