50 EuroPak-15a Receiver User Manual Rev 5
Chapter 5 Commands
5.3.4 CLOCKADJUSTAll oscillators have some inherent drift. By default the receiver attempts to steer the receiver’s clock to
accurately match GPS time. If for some reason this is not desired, this behavior can be disabled using the
CLOCKADJUST command. The TIME log can then be used to monitor clock drift, see Page 97.
1. The CLOCKADJUST command should only be used by advanced users.
2. If the CLOCKADJUST command is ENABLED, and the receiver is configured to use an external
reference frequency (set in the EXTERNALCLOCK command, see Page 54, for an external clock
- TCXO, OCXO, RUBIDIUM, CESIUM, or USER), then the clock steering process will take over
the VARF output pins.
3. When disabled, the range measurement bias errors will continue to accumulate with clock drift.
4. Pseudorange, carrier phase and Doppler measurements may jump if the CLOCKADJUST mode is
altered while the receiver is tracking.
5. When disabled, the time reported on all logs may be offset from GPS time. The 1PPS output may
also be offset. The amount of this offset may be determined from the TIME log, see Page 97.
Abbreviated ASCII Syntax: Message ID: 15
ASCII Example:
CLOCKADJUST DISABLE
CLOCKADJUST SWITCH
Field Field
Type ASCII
Value Binary
Value Description Binary
Format Binary
Bytes Binary
Offset
1header This field contains the Abbreviated ASCII command name.
See Section 4.1 on Page 31.H 0
2switch DISABLE 0Disallow adjustment of
internal clock. Enum 4 H
ENABLE 1Allow adjustment of
internal clock.