Reconnaissance drones without GPS/GLONASS: how Russia navigates its drones across the front

Undetected across the front line and far into the Ukrainian rear: Russian reconnaissance drones operating in radio-silence mode have repeatedly managed this in recent months. It is usually noticed only when it is too late – namely when high-value targets far behind the front are hit with pinpoint accuracy by Russian long-range rocket artillery.

On the Ukrainian side there is great concern that these incidents – isolated, but regular – could give Russia a strategic advantage. Work to uncover the secrets of Russian drone navigation is correspondingly intensive.

From the Ukrainian perspective, the problem is that the drones are not radio-guided and that almost all satellite navigation frequencies in the area are jammed. This is primarily the work of the Russians themselves, who hope to degrade the western weapon systems supplied to Ukraine.

Three types of Russian reconnaissance drones

The Russian army essentially uses three models: the petrol-powered Orlan-10, considered outdated, together with its larger version, the Orlan-30; the electrically powered Zala 421-16 from Russia's Kalashnikov group; and the Supercam S-350, which is also driven by an electric motor. Production of the Orlan alone has risen 53-fold compared with pre-war levels.

Radio navigation for the rough position, camera image for the exact one

For approximate positioning, the drone relies on tried-and-tested radio navigation: signals come from at least two, possibly more transmitters. From the signals' propagation times and by triangulation, the position can be narrowed down roughly – to about one square kilometre.

The drone handles everything else autonomously. Its reconnaissance camera takes a photo of this area, in which reference points are identified; these are stored in the drone's memory as terrain maps.

This allows a very precise position fix with comparatively little computing power and energy, because instead of hundreds of square kilometres only one has to be searched for reference points. Both properties are an advantage for any drone – but for Russia they are essential.

A drone's energy supply is always tightly limited. When it comes to computing power, what counts above all in wartime is “price”, “performance” and “availability”.

Russia is currently able to produce more reconnaissance drones than Ukraine has suitable air defence missiles. The drones cover the transit flight across the front into the rear at high altitude. There they can no longer be seen with the naked eye and are out of range of the inexpensive man-portable air defence systems (MANPADS).