Explainer | What happened to Hong Kong’s pre-National Day drone show? The Post talks solar storms

Consultant working with organisers attributes decision to significant ionospheric interference affecting GPS signals used to control drones

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Hong Kong was forced to cancel it’s pre-National Day drone show on Monday. Photo: Sam Tsang

Published: 8:34pm, 1 Oct 2024Updated: 8:54pm, 1 Oct 2024

A highly anticipated drone show at Hong Kong’s West Kowloon Cultural District planned for the eve of National Day was postponed for more than an hour and then cancelled, with authorities attributing the decision to a “meteorological factor”.

A consultant working with organisers said the event was cancelled due to significant ionospheric interference that had affected the accuracy of the GPS signals used to control the devices.

1. What is the ionosphere?

Jennifer Yip Ling, a scientific officer with the Hong Kong Observatory, said the ionosphere was part of the Earth’s upper atmosphere, where extreme ultraviolet and X-ray solar radiation ionised atoms and molecules, creating a layer of electrons.

The ionosphere is located at an altitude of 80km (49.7 miles) to about 600km. Commercial aircraft fly at an altitude of about 10km.

The ionosphere is split into three different layers due to variations in solar radiation and the density of atmospheric components.

It also reflects and modifies radio waves that are used for communication and navigation.