A flight track that survives the loss of GNSS

Inertial is an inertial flight recorder for the cockpit of a light aircraft. When the satellite signal is jammed, denied or simply weak, it keeps estimating where the aircraft is — from the phone's own motion sensors and a physical model of how your aircraft flies.

The problem it addresses

GNSS jamming and interference have become ordinary over large parts of the world, and they rarely present as a clean outage. They present as a track with a hole in it, or as a track with a confident and wrong section — discovered on the ground, after the flight, when nothing can be done about it.

How it works

Mount your phone as you normally would. Inertial records from the satellite receiver and, at the same time, from the phone's own motion sensors: the accelerometer, the gyroscope, the magnetometer, and the barometer on devices that have one. When the satellite signal degrades or disappears, it goes on estimating position from motion alone.

It works in two tenses:

Live, in the cockpit, on the phone, with only the past available.
After landing, when the whole flight can be smoothed in a second pass — which improves the estimate everywhere, not only across the gaps.

Your aircraft, not a generic vehicle

Dead reckoning from a phone's sensors alone drifts, and it drifts quickly. What makes it useful is knowing how the aircraft moves, so Inertial applies the strongest model it has for the type you fly:

Powered light aircraft — coordinated flight, and the speed and power regime you actually cruise in.
Gliders and sailplanes — a known polar, and an aircraft that is nearly always either circling in a coordinated turn or in straight glide. These are the strongest constraints available to the method.
Engine-out flight, and practice forced landings — the moment the propeller stops, a powered aeroplane becomes a glider, and the same strong constraints apply. That is also the moment you would least like to lose the track.
Paragliders and hang gliders — slower, with their own turn and sink behaviour, treated as their own class.

You tell the app what you fly, once.

On your device, and nowhere else

No account. No sign-in. No server. No advertising. Your flights are written to your phone and stay there until you choose to export or delete them. Inertial sends nothing anywhere, which is a design decision rather than a setting you have to go and find.

Recordings export to IGC and KML through the Android share sheet, for your usual flight analysis.

What it is not

Inertial is not a certified navigation instrument, and it is not for flying by. It gives no steering guidance, no airspace, no final glide and no traffic, and it must not be used to navigate an emergency. It does not replace your logger where an approved logger is required. It is a recorder and a track reconstructor, to be read after the flight. Fly the aircraft on your certified instruments.

Status

Inertial is in development and is not yet on Google Play. It will be a one-time purchase, with no subscription and no in-app advertising.

If you fly and would like to hear when it is available, write to support@flyinertial.com.