GPS-based verticality approximation of an experimental fully-airborne VLF antenna

Verticality, a parameter calculated as a difference between the positions of the upper and lower ends of a long, aerostat- or aircraft-supported antenna, divided by the antenna’s length, is an important parameter describing the spatial form of the very low frequency (VLF) antenna, crucial for the assessment of its operation efficiency. In this paper, a fully-airborne (not anchored) VLF test antenna is analyzed in the terms of its verticality during the ascending phase of its flight, including flight in the proximity of the stratospheric jet stream. The unsynchronized GPS data from the antenna’s proximities are used to determine the verticality with defined accuracy. The limits of this method are shown, with the possible ameliorations in order to refine the data collection and expand the range of their usefulness towards the overall antenna design.