NavList:

As with aircraft crashes, ship collisions, and now it would appear unmanned aerial vehicle (UAV) incidents, it’s probably not worth speculating what went wrong from the small amount of information available, often at second or third hand, from the media.  For example, what is meant by ‘crash’?  Did all of these UAVs fall totally out of control to the ground, or did they damage themselves attempting automatic forced landings in a particularly built up area with tall buildings and urban canyons?  What do the media mean by GPS?  Where these UAVs using just GPS signals from space, or where they using a mix of GPS, Glonass, and BeiDou signals?  It was Hong Kong after all.  Why did only 40/100 UAVs ‘crash’?   100 UAVs is a large number to assemble in one go; where there any significant differences between models?  And as Frank says GNSS guidance is only part of the PNT solution.  Was the PNT sequence stored on board each UAV before take-off, or was it being transmitted in real time from the ground as the show progressed?

With air crashes and ship collisions investigators usually take months to explain what happen, and they have all the available facts to work with.  Hopefully, it won’t take quite so long for UAVs, but I for one am trying very hard not to speculate in the meantime. DaveP