CHAPTER ONE
1.4 SPECIFICATIONS
The electrical, physical, and environmental specifications for the ExacTime are listed below.
1.4.1 GPS SUBSYSTEM
A. TIME ACCURACY
After power-up, when LOCKED and using 200 Position Averages, will be better
than ± 125 nanoseconds relative to UTC with SA on within:
4 hours using a Rubidium oscillator.
2 hours using an Oven oscillator.
1 hour using a TCXO oscillator.
B. FREQUENCY ACCURACY
90% of the time, better than: 1E-9 for TCXO
1.5E-10 for Oven (OCXO)
1E-11 for Rubidium
C. POSITION ACCURACY
100m 2dRMS with SA
Less than 25m SEP without SA.
D. MAXIMUM VELOCITY
515 meters/second. (1000 knotts/hour).
E. TRACKING CHANNELS
Eight parallel.
F. RECEIVER FREQUENCY
L1 1.575 GHz, C/A Code.
G. ACQUISITION TIME
Time to first fix is less than 5 minutes with timing accuracy better than two μS and
frequency accuracy better than 1E-8. Full system accuracy with oven (OCXO)
oscillator is provided within 2 hours after LOCKED.
1.4.2 TIMING OUTPUTS
Rear panel BNCs J4 through J9 can output a 10MHz sine wave, IRIG B (AC), various pulse rates,
or alarm outputs. The following is the standard output configuration for the rear panel BNC
connectors. To change the outputs from the factory set standard configuration, see the paragraph
titled “Timing Outputs” in Chapter Two and the paragraph titled “Optional Pulse Rate Outputs” in
this section of the User’s Guide. Each output is via a 50Ω driver.
1-4 ET6xxx ExacTime GPS TC & FG (Rev C) Symmetricom Inc
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