The GDGPS System provides 1 Hz corrections to the GPS
spacecraft position (X, Y, Z coordinates), and clock state
in the GPS broadcast ephemerides. They
are globally and uniformly valid - just like the broadcast ephemerides.
Adding the corrections to the broadcast ephemerides gives the precise
orbit and clock state of the spacecraft, accurate to better than 20 cm 3D RMS. In
fact, we derive the orbit and clock corrections by subtracting the broadcast
ephemeris from our precise real-time orbit and clock solution product.
The corrections for all GPS satellites are available as a low bandwidth
(44 Bytes/sec) binary data stream from our Operations Centers through a
variety of communications channels.
The correction message includes velocities of the orbital corrections, enabling the user to propagate
the corrections into the future, and be resilient to short data outages.
Look at our live performance monitor to see real-time point-positioning
carried out, utilizing our correction data stream.
The following table summarizes the key attributes of this product.
< 20 cm 3D RMS
< 20 cm RMS (after de-biasing and de-trending)
< 10 cm RMS
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