Bob Pasker wrote:
I wonder if the reason for requiring high-resolution TSO'd GPSs is that
ADS-B will be used for IFR separation and for fast-moving aircraft, so
high-resolution position and updates is an absolute requirement, a la fast-scan radar.

Let me try to say it one more time, it is *not* about resolution, or even
accuracy (consumer GPS chipsets have no problem doing either) it is about
reliability and failure detection. The FAA is clearly concern that they
need this reliability so ADS-B can be used as the primary means of
controlling aircraft separation in the NAS.