Until Wednesday only the Chinese government and military had access to the interface to use the signal from the Beidou constellation. Then the interface was made public. To be technical:
an official version of the complete interface control document [pdf] (ICD) for the nation’s BeiDou Navigation Satellite System (BDS) Open Service signal-in-space (SIS) [was made public]
What that means is that now other organizations can build recievers and devices using those signals. That's the good news, along with the specs: .
location to 10m (33ft), their velocity to within 0.2 metres per second, and clock synchronisation signals to within 50 nanoseconds.
The bad news is that receiver chips are far more expensive than comparable GPS chips and the constellation only works well in Asia. With 40 more satellites planned it should be valuable worldwide - in about 2020.
- BBC via @RDQ_geography
