Pilot Tethered Systems

A tethered drone is about what you’d expect: a drone on a cord.

Overview

Drone tethers are an under-used technology. A “tether” in this case is a lightweight cable that carries power and sometimes data between an operator station on the ground and a drone in flight. Right now tethers are primarily used to allow for arbitrarily long mission times for surveillance and mapping applications. Some of this is for construction, surveying, and mining applications, but mostly tethered drones are used as a loitering observation platform by either or private security or military.

Recently, one drone tether company, Vicor, demonstrated an 800v tether system that could deliver 10kw to a drone. I imagine the initial target customer for this technology is the military, but what civilian applications could 10kw of tether power enable? The main advantages of all that power are arbitrarily large lifting capacities and unladen performance specs with unlimited up-time and no heavy batteries to cut into the payload. (though there is the altitude-dependent weight of the tether itself to consider) This makes the high voltage tethered drone the perfect to fill the tug boat niche in our delivered-by-drone future.

Why do we need a tug boat drone? Because the delivery-by-drone model will scale much better in rural areas if the VTOL and cruise cases can be separated into two separate aircraft. Just look at the drone delivery systems being used today by Wing and similar: They’re generally trying to cram both a fixed-wing aircraft for cruising efficiency and a multirotor for hover capability into the same airframe and it basically means that they are ALWAYS carrying around unnecessary mass since they’re really only using one flight system or the other at a time. Why not split the functions into two aircraft: a fixed-wing aircraft designed to cruise or loiter efficiently on its limited battery and a high voltage high power VTOL multirotor on a tether designed to dock with the loitering fixed-wing in order to exchange a package.

To be sure, there’s a lot of R&D work to be done with drone-to-drone docking. It’s not something that’s really done right now and we’d be the first that I know of to commercialize such a thing. The good news is that it should be an easy problem if we limit the scope appropriately. A well-designed box for the drone shipments that can be easily grappled from above or below using a lightweight but solid mechanism could go a long way towards making the controls problem simple. Similarly the packages and/or drones can include whatever tracking or marking hardware is needed so that final docking navigation can be handled reliably by on-device computing resources. We can also make the problem easier simply by making the tethered drones powerful enough to carry both the package and the fixed-wing drone. With an extremely overpowered tethered drone, we could essentially disregard the flight dynamics of the fixed wing aircraft and go for a simple “punch the dock, then recover stability later” docking procedure.

Tethered tug drone use cases:

• package handoff and retrieval from fixed-wing carrier drone

  • the consumer-side (receiving) drone my be battery powered, but tethers make more sense for hub operations.

• launch and recovery of fixed-wing carrier drone

• mid-air battery charging, battery swaps, or re-fueling of fixed-wing drones

So in summary, Pilot Tethered Systems this isn’t so much a “drone tether company” as it is a “drone docking and handoff” company that is enabled by drone tether technology. Of all the current ideas, this is the most out-there in terms of level of effort required before positive ROI. It would be a gamble that would require funding for a decent sized R&D effort, but could also pay off big. This one is the closest to your stereotypical “startup” and as such would likely benefit from the involvement of VC in a way that many of the other ideas shared here would not.