Australia's new (or pre-existing?) SPAD (anti-submarine?) research.

Australia's Defence Science and Technology (DST) organisation has been developing a single-photon avalanche detector (SPAD) that may one day have anti-submarine applications. Below is a summary of the DST Media Release of April 10, 2019:

When suspended from a hovering drone just above the sea surface the aim is to dip the SPAD detector underwater. Working with a laser system SPAD may one day detect underwater objects (like mines, UUVs and submarines) by sensing low-light reflections.

[Pete Comment: There seems to be similarities with LIDAR].

SPAD is funding by the RAAF's Plan Jericho which, in part, is researching advanced sensors.

The SPAD system has been tested from a wharf at the Osborne shipyard in Adelaide, South Australia, then off a boat at sea near the Western Australian naval base, HMAS Stirling. 

"While the team successfully demonstrated underwater detection, Mau says there's still plenty of room for improvement, including optimising the optics and image processing."

The current SPAD chip is "a mere" 32×32 pixels of resolution and needs to be upgraded to 256×256 pixels to improve the sensor to practical effectiveness.

From dipping the SPAD sensor off a wharf and then off a boat at sea initial trials have been made with a custom-built, heavy-lift, unpiloted multicopter off the South Australian coast. 

FURTHER READING

A broader and I would say closely related principle is https://en.wikipedia.org/wiki/Single-photon_avalanche_diode [which also carriers the acronym "SPAD"].

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Separately, but not connected to the DST research, below is an example (with Australian connections) of a Heavy Lift Unpiloted Multi-copter carryng delicate equipment.

Pete