Accuracy is of course important, but perhaps more important is how we build in scaleable redundancy as the number of satellites reduce. It's very frustrating when my sat nav or run keeper can't get a good signal, this inevitably leads to people dropping services or at least using them less. They key question is at what level is the service too compromised? and what's the next best alternative?

Wonder how feasible it would be to have a single GPS+GLONASS+Galileo chip that automatically feeds you the service(s) with the best signal; without murdering your battery?

Down to 1 meter is open access, down to centimeters is commercial. I thought the open access variant would merely be on par with GPS and you would have to pay for better positioning.