As far as communications are concerned, these Metro systems will have leaky feeder and other systems in place to make sure there are adequate communications underground, but what about the location of personnel? GPS and other GNSS signals are very weak and so there is no chance that standard location technologies can be used in underground emergencies.

This video highlights how Chronos’ partnership with SyntonyGNSS can deliver underground location using standard equipment such as the iPhone for when this is really needed.