We are in the process of upgrading CGPS sites in California to high-rate (1-2 Hz), low latency (<1 s) operations, and integration of these data with seismic data in the region. So far 40 sites have been upgraded including the "Parkfield", "Orange County", and "Diamond Valley Lake" networks, and a concerted effort is underway to upgrade 30 more sites in Riverside County. Here we describe:
(1) Displacement waveforms from the San Simeon earthquake measured in real-time by sites in the Parkfield network. These are the first near-field measurements of a large earthquake with a high-rate GPS network.
(2) Noise characteristics and offset and rate sensitivity of 1 Hz GPS position data on medium scales (10's of kilometers) and 2 Hz data on the 50 m baseline at Pinon Flat Observatory.
(3) Communications, hardware, and data handling infrastructure developed to accomodate these and future upgrades.