arstechnica.com:
Was a Russian Su-24 strike bomber over Turkish airspace earlier today when it was shot down by a Turkish F-16 fighter, as the Turkish government claimed? Or did it, as the Russians have claimed, fly in Syrian airspace and never cross the Turkish border? The Turkish and Russian governments have published conflicting evidence on the plane's location as accusations fly between the two sides. But it's entirely possible both sides are right—based on different data sources.
With precision satellite navigation and radar systems available to both sides, one might think that it would be relatively simple to both know where the border was and avoid it or know for certain which side of the border the plane was on when it was shot down. But the Russians have published their own version of navigational tracking data that shows the Su-24 flying south of a part of the Turkish border that juts southward into Syria. The Turks claim that the jet, while clearly not mounting an attack against Turkey, was over a mile into Turkish airspace and had been repeatedly warned that it was on a course that would cross the border.
But given the Russian aircraft was only in Turkish airspace for a few seconds (and only penetrated, even by the Turks' accounting, by a little more than a mile), it's still possible that the GLONASS system used by the Russian military for navigation may have given the aircrew different information than the Turks had. GLONASS has fewer satellites than GPS, and more of its satellites follow the same orbital path. That makes positioning errors more likely. And with the complex border between Syria and Turkey (and Russia's operations against Syrian rebels taking them extremely close to that border), a slight miscalculation in flight path could put Russian pilots in Turkish airspace.
Was a Russian Su-24 strike bomber over Turkish airspace earlier today when it was shot down by a Turkish F-16 fighter, as the Turkish government claimed? Or did it, as the Russians have claimed, fly in Syrian airspace and never cross the Turkish border? The Turkish and Russian governments have published conflicting evidence on the plane's location as accusations fly between the two sides. But it's entirely possible both sides are right—based on different data sources.
With precision satellite navigation and radar systems available to both sides, one might think that it would be relatively simple to both know where the border was and avoid it or know for certain which side of the border the plane was on when it was shot down. But the Russians have published their own version of navigational tracking data that shows the Su-24 flying south of a part of the Turkish border that juts southward into Syria. The Turks claim that the jet, while clearly not mounting an attack against Turkey, was over a mile into Turkish airspace and had been repeatedly warned that it was on a course that would cross the border.
But given the Russian aircraft was only in Turkish airspace for a few seconds (and only penetrated, even by the Turks' accounting, by a little more than a mile), it's still possible that the GLONASS system used by the Russian military for navigation may have given the aircrew different information than the Turks had. GLONASS has fewer satellites than GPS, and more of its satellites follow the same orbital path. That makes positioning errors more likely. And with the complex border between Syria and Turkey (and Russia's operations against Syrian rebels taking them extremely close to that border), a slight miscalculation in flight path could put Russian pilots in Turkish airspace.
