Nanosynchronization of multiple transducers requires a common clock source, such as the time signal from GPS. But when no GPS signal is available, synchronization is still possible, assuming you have a very stable clock, where an atomic clock is as good as it gets.
Symmetricom has now built a portable atomic clock into a chip giving with a drift of 0.3 parts per billion per month. In more partical terms this means that after a month, your time will be off by a maximum of about 800 μs, or about 1 second in about 30 years. (Stationary atomic clocks are accurate to 1 second in about 1 million years).
This new device, selling for about 1500 USD, will initiallly have specialized applications in advanced instrumentation and defense applications.
Now it will be possible to keep synchronization when the transducer moves indoor or underwater or other places where GPS is not available. And it will be possible to re-synchronize the portable atomic clock to the “GPS time” whenever GPS signals are available.
I see this type of device very relavant for many of the types of applications discussed on this blog, where low cost is not the primary objective. With time, we hope that “Moore’s” law will help drive down the cost of the device and hereby expand the number of applications.