Both tower-mounted and helium aerostat platforms have demonstrated the importance and capability of sustained multi-day and multi-week surveillance from elevated positions. However, both platforms have inherent limitations. Towers, as fixed assets, require significant financial investment, ground access, and ongoing maintenance. Additionally, once their locations are known, adversaries can identify blind spots and develop alternative paths to avoid the surveillance coverage of tower sensors. Helium aerostat platforms inherit the financial, infrastructure, staffing, and maintenance requirements from their military origins. Like towers, aerostats are fixed assets limited by ground support requirements and can be avoided once identified. Despite their remarkable downward-looking capability, aerostats are also susceptible to adverse flight conditions.

Recent developments in commercial-off-the-shelf (COTS) unmanned aerial systems (UASs) and power tether systems offer a cost-effective tactical alternative to towers or helium aerostat platforms.

Tethered drones are quad-, hex-, and/or octa-copters connected to a base station via a tether that provides continuous power. Because of the tether connection, the drone's size, payload capacity, and flight time are not restricted by onboard power supply limitations. Very large sensor arrays can be deployed for hours or days at a time, provided a reliable power supply is maintained to the tether system. The external power source also enables drones to maintain position in relatively high winds that would exhaust the power reserves of free-flight drones and threaten aerostat platforms.

As tethered devices, these drones fall under the same FAA restrictions as aerostats (under 500 feet). However, unlike aerostats, tethered drones have a significantly smaller profile, making them less intrusive and less overt as surveillance platforms. By leveraging COTS quad-, hex-, and/or octa-copter platform components, tethered drones are low-cost and require minimal maintenance.

Typically transported and launched from Pelican-style cases or larger containers, these drones operate as single-button launch and retrieval systems using COTS flight control software designed for tethered platforms. The tether is automatically spooled out and retrieved from the base station. As a safety precaution, the drones carry backup batteries to enable controlled landing in the event of power failure.

The size and capability of the platforms are mission-defined and can include electro-optical sensors, thermal imaging, and other specialized sensors. The platforms can transmit control and sensor data through the tether or use radio and/or Wi-Fi transmission. With available power and altitude advantages, Wi-Fi can be transmitted over large areas, providing ground assets with live feeds accessible on cell phones and tablets.

Best practices for tethered drone deployment involve circumstances requiring ad-hoc sustained surveillance from a controlled base with minimal cost and minimal observable profile. While these platforms can operate at altitudes higher than FAA-approved levels, they are best suited for low-level, semi-covert surveillance over sustained periods. The drones can also operate over water or in desert environments and feature "follow" capability, allowing deployment from moving platforms in unobstructed areas. This provides superior littoral and desert operational capability.

Tethered drone surveillance platforms function as tactical assets that complement existing land and sea monitoring capabilities with low-risk, low-cost, rapid acquisition-to-deployment protocols. While equivalent capability does not exist in conventional technical/sensor inventories, this technology can be acquired and deployed within weeks rather than months or years, at lower cost than any comparable airborne sensor platform. Practically, this translates to immediate enhancement of tactical surveillance capability with minimal acquisition or logistic footprint. This rapid deployment is possible through the use of lightly modified existing UAS platforms and COTS tethering systems designed to accommodate various UAS designs and capabilities.

Tethered drones can conduct multi-hour or multi-day flights with significant payloads. Since power is supplied through the tether, these platforms can employ larger motors and operate in higher wind conditions. This power advantage also supports larger payloads, including advanced electro-optics and thermal imaging systems.

Unlike tethered aerostats, quad/hex/octa-copters have much smaller form factors, making them difficult to detect at distance and providing a more discreet surveillance option.

COTS tether systems now incorporate onboard intelligence for tether and platform management, enabling automatic launch and recovery through simple single-button operation.

While dedicated tethered platforms exist, using COTS UASs equipped with tethers allows deployment of lower-cost, mass-produced platforms and associated components.

COTS components enable off-the-shelf acquisition, simple configuration, and immediate deployment capabilities.

Under current legal interpretation, powered tethered platforms are equivalent to kites, exempting tethered UASs from Certificate of Authorization (COA) requirements and other restrictive FAA regulations.