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Tactical Communications using a Vertical Height Antenna (VHA)

OCTOBER 2020, THU 08

What is a VHA?

A Variable Height Antenna (VHA) refers to a drone which is equipped with a radio and antennas in order to allow the operator to quickly set up a communications relay node instead of using a mast.  A VHA may be tethered or non-tethered.  Figure 1 is a system based on a tethered drone that is carrying a radio and multiple antennas.

In the case of tethered VHAs, the ground station provides the electrical power, communication data and control signals to the drone. It contains an automatic winch system that maintains the proper cable length and tension with the drone.   When powered from the ground, the tethered drone can hover in a stable position up to a height of 120m or more and for an unlimited period of time, weather permitting.


What are the benefits of using a VHA over a traditional mast?

From a communication point of view, the VHA provides multiple benefits and flexibility over the standard 15m and 30m physical mast systems.

- It provides additional height to overcome major obstacles such as structures or terrain features which prevent or degrade radio communication links. Otherwise, additional masts need to be deployed around the obstacles to establish the links.

- When the radio is configured as a radio relay or as a mesh node, the VHA supports longer link distance, thus reducing the amount of required links compared to the same antenna mounted on a mast.

- The additional height can be used to increase the area coverage on the ground, allowing a larger area to communicate with dismounted soldier radio systems.

When equipped with a camera, the VHA system can also provide better situational awareness due to its height.

In terms of deployment and logistics, VHA’s have certain advantages compared to masts. The VHA system can be easily be transported in two carrying cases - one containing the VHA, radio, and antennas and another with the ground station. Assuming the radio and antennas are already installed on the drone and the batteries are charged, it can take less than fifteen minutes to setup the system.

What are some considerations that need to be considered when using a VHA?

There are constraints that the operator must consider when deploying a VHA:

- The radio and antenna equipment weight that can mounted on the VHA depends on the VHA payload or capacity. The Ultra ORION X510 radio is a good fit and can easily be used with omnidirectional antennas due to its small form factor.

- Although somewhat small, VHA’s are visually detectable from a distance, which could lead them to be more susceptible to threats than a mast.


Has Ultra tested its radios on a VHA?

Yes.  The ORION X510 radio has been integrated and tested with a tethered drone.  This configuration was demonstrated to both the U.S. Army and Special Operations Forces (SOF). The radio was configured as a mesh node and used to extend the reach and coverage of the mesh network in an urban area with multiple structures. It was also used to connect to dismounted handheld mesh radios.

How do operators interface with the system?

The operator uses a mobile command console such as the one illustrator below, which includes a network management screen to set up the radio links and configuration (left view), a screen to show the drone camera view (right view), and another screen to control the drone itself (bottom right view).