What is submarine Drone ?
A smaller, but still large autonomous submersible, like this LDUUV Sea Stalker.
Or this - I don't know this one's name.
Algorithmic wizardry to navigate, "eyes" and "ears" to monitor items of interest and torpedo-esque propulsion. Basically like any existing submarine, but without people controlling it, usually, they can be remotely controlled too.
According to the US Navy, they've made some propulsion breakthroughs to allow smaller AUVs a greater range.
“I am continuously amazed with the underwater breakthrough technologies in power, power generation, and navigation and sense and avoid,” Winter said. “When people say, ‘I can’t see that happening. There’s no way that can be,’ I say, ‘Excellent! Put that on ONR’s list.’”
...
Mabus said the LDUUV would help the Navy develop “increased subsurface endurance and autonomy” — read that to mean subdrones that can operate with minimal human intervention close to vital areas and targets. The LDUUV currently has an undersea endurance of 30 days but the eventual goal is to stretch that to years. (Original builder specifications can be found here.)
Their missions include ISR, electronic surveillance and intelligence, possible cable splicing, mine hunting and ASW options, once armed. Their modularity allows them to have a more flexible payload and adapt to emerging threats or interests.
What are the advantages ?
They allow a submarine to survey their surrounding at greater distances without compromising their low profile. Basically, these can do everything a traditional submarine can, apart for launch weapons or divers... for now. Some autonomous systems are being developed for those purposes too.
The US Navy's next generation SDV is said to have an autonomous mode for diver delivery.
How many countries posses such things ?
Many, it's a proliferating technology. The US is featured in the article, China has some autonomous deep-ocean submersibles, but has yet to demonstrate an LDUUV publically. I would image they are in the game too. India, Norway, Japan, the UK, many nations have AUVs.
India.
Norway.
UK.
Many countries have these technologies, but only the US has the tactics and doctrine to integrate them with a sub-surface force right now. Others are likely to develop this capability too.
Does China have something similar?
Of course they do.
Qianlong I is a 6,000-meter-rated Chinese AUV that performs near-bottom topography measurement, undersea photography and hydrological parameter measurement.
It's not the system, it's the doctrine and tactics they don't yet have.
