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A history of the DJI wireless system, does Walksnail use DJI technology? – SUAS news

Last week, Joonas from fpv.wtf posted some information on Twitter about what we believe to be the origins of the DJI digital FPV system chipset known as the P1 and what Waslksnail can use in the Avatar system and today , I wanted to develop this.

There has been a massive amount of guesswork and speculation about the Avatar system and whether it is in fact DJI, based on the DJI chipset or just something similar. To better understand this, we must first look at DJI and the chipsets they have used over the years from Leadcore, Artosyn and others. Leadcore To begin with, we must first understand who and what is Leadcore, the company was a fabless chipset design company which was a subsidiary of Datang Telecom Technology Co., Ltd, which itself was a subsidiary of the partly Chinese state-owned company “China”. Academy of Telecommunications Technologies”.

Leadcore’s core business was the development of application and IP processors for mobile devices. In 2014, they were the sixth-largest smartphone SOC provider in China. Its LC1860 chipset has been widely used in devices across China. Leadcore seems to have faded somewhat in 2018 when its parent company Datang Telecom Technology apparently ran into financial difficulties and faced delisting from the Shanghai Stock Exchange.

However, their chipsets are still used in many Autel drones today, and their IP address lives on in other chipsets. Artosyn Shanghai Kuxin Microelectronics Co.Ltd, known in China as Kuxin with Artosyn brand, is a Chinese fabless chip design company specializing in 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 systems they used before and offered long range HD video and RC control link. It was originally driven by an Altera Cyclone V FPGA in the I1, then in the Phantom 3 Advanced and Pro, then later in the Phantom 4. In later variants of these models such as B, C, DJI remotes replaced the FPGA with a pair of SDRs. chips from Artosyn, the AR8001 DSP and AR8003 RF transceiver.

The overall system was the same, just 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 used Lightbridge 2 again, but this time the Artosyn AR8001 was gone and replaced with a very similar looking chipset but with a DJI logo on it. It is believed to have always been the AR8001 or at least a variant and shows that DJI was starting to “tinker” by 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 Lightbridge, but the big technical change was that it was an SDR. While Lightbridge was also an SDR with Artosyn chipsets under the hood, the Artosyn chipsets were gone and the Leadcore LC1860C paired with Imagination’s IE1000 front-end transceiver took over all of the radio system work.

At this point it’s fair to summarize that DJI had been working on using the built-in LTE SDR modems and ARM cores to drive the system wirelessly for some time on the Leadcore chipset and felt it was now able to move on to this fully. DJI continued to use the LC1860C Leadcore chipsets as the SDR in all Ocusync and Ocusync 2 models from then on, including the Ocusync Air FPV system, DJI White Goggles, and Goggles RE. O2 which was released with the Mavic 2 was a code improvement over Ocusync in many ways and even offered some two-way compatibility.

Quietly during the lifetime of the Mavic 2, DJI released a B remote with the enterprise edition, which in itself was nothing particularly unusual as we’ve seen in the past, but there was a change hidden quite important and that is that DJI replaced the Leadcore LC1860C with a new chipset unknown at the time.

This new IC seen in the FCC filings has a Leadcore logo among other things, but looked different than anything before, but later we now know looks a lot like what was to follow. This brings us a bit to the present day and the DJI Digital FPV system.

With the release of this DJI introduced the P1 chipset. This new SOC was considered a custom DJI ASIC that allowed them to develop a lower latency system than what we had seen before. Over time and with a tremendous amount of work from tmbinc, bri3d and joonas, we now know that the P1 is really just a custom, dedicated Leadcore IP chipset with tweaks to the LTE baseband that go beyond the simple use of modems as in Ocusync 2.

It’s nothing specifically magical, it’s just more customized for that use case with the unnecessary “bits” 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 DSPs and a few other bits.

They basically use the same CPU core + DSP configuration as the Leadcore chipset and it’s probably running custom software for their LTE based OcuSync and that’s what makes the difference. The first A7 core on the P1 runs Linux, while the second runs baseband RTOS in combination with dedicated DSPs. All of DJI’s later drone models including the M200 V2, M300, Mavic Air 2, Air 2S, Mini 2 and Mavic 3 all use the P1 chipset with their remote controls using either the P1 or its smaller sibling the S1 . The P1 has become DJI’s primary chipset for all of their Ocusync systems now.

Leadcore chipset in Autel and Herelink & Artosyn in other manufacturers Along with DJI, Autel was also found to use Leadcore chipsets in their drone wireless systems, even Herelink Pinecone S1 SOC was co-developed by Leadcore and Xiaomi.

While others like Autel use Leadcore, Zero Robotics and Hollyhand use Artosyn chipsets with similar functionality. It should be noted though that DJI is way ahead of everyone else and there is a clear history and relationship between DJI, Artosyn and Leadcore that seems to have given DJI the edge over everyone else. So what does all this mean?

From a general perspective, you can see this as the Chinese state government has tasked parts of its wireless industry with creating rival chipsets like Qualcomm for the domestic smartphone market. This allowed Chinese manufacturers like DJI to have much deeper access to the LTE baseband modems in use than what we’ve seen in the US and EU, allowing them to develop the system that we see today.

Who actually did the work isn’t known, but it’s likely that with the clear relationship between all the companies, there were a few hands to develop low latency wireless systems that let the competition upright. Today we see chipsets from Artosyn such as the older AR8020 which seem to offer much of what DJI has in the P1, and the newer AR8211 has more features with H265 and 4K30 capabilities.

It’s what you might call off-the-shelf silicon, but accessing it is a lot more complicated than ordering from Mouser or Digichip. They are very well kept out of public hands. It’s very interesting how these Artosyn chipsets have developed over the last few years, especially since Leadcore as a company seems to have gone public, it’s very likely there’s DNA and ownership leadcore intellectual. Did DJI shake up the US government?

A final interesting point on DJI on this is the rumors that have been circulating for some time that the release of the DJI FPV system coincides with the US trade ban and there has been 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’s largely incorrect, but I’ll add that we haven’t seen anything like DJI has done with LTE baseband modems in the West and although it may not be- to be not from a US chipset the original LTE base IP origins have ties to Qualcomm and/or Ceva and it’s not at all incredible that what they’ve done is shaking some cages in the US and in the 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 that the new Artosyn chipsets certainly fit the bill, the AR8211 has more features than the DJI P1 with H265 and 4K30 capabilities. I wouldn’t be shocked to see this or some variant of it in this system. We know that Artosyn works with partners on FPV, as they confirmed this to Joonas when he contacted them.

At the end of the day, the simple reality is that DJI is just doing what it’s always done and has developed its system based on other people’s technology and IP, that’s what DJI does best. They can do a custom implementation in the modem, but it’s nothing magical. It looks like Artosyn is doing the same and Avatar is using it. If so, it’s not a copy or clone, it’s just a similar implementation based on the same underlying technology.

Final remarks. I want to say a huge thank you to

Firstly Joonas for the help, information and support that helped put this together, plus a big thank you to tmbinc and bri3d for all the amazing work they’ve done to help us sort this all out .

Joona Twitter https://twitter.com/fpv_wtf?s=20&t=q9...

fpv.wtf website https://fpv.wtf/

Mad. https://twitter.com/madrc1