Fascinating article. About this: > Before GPS, navigation systems used a technique called ‘dead reckoning‘. Dead reckoning relied on sensors to determine distance traveled and direction of travel. However, no sensor is perfect. As a result the further you travel the greater the errors build. Pretty quickly you have no idea where you are. > To solve this problem Etak invented ‘augmented dead reckoning’. This used a pr…
Civilian systems are usually not designed to work in a hostile environment, not only it is costly for a situation that is unlikely to happen in normal use, but authorities usually don't like it when such technology is available to the public. As a result, it tends to be classified. They want to be keep the advantage over enemies and criminals.