11.2 Standard Command Set
101
Receiver Status
Command:
SR
SR returns the current receiver status.
Response:
V=vv S=ss T=tt P=Off
C
Format: vv = number of satellites, visible to the antenna, per almanac; ss = relative signal strength (range:
0 to 100, nominal value = 45); t = number of satellites being actively tracked (up to 32); P = Off, indicates
that the time dilution of precision (TDOP) calculation is not being performed. Returns 1.0 – 99.0, depending
on satellite geometry, when TDOP calculation is being performed. A TDOP calculation is not performed if
less than 3 satellites are visible.
System Status
Command:
SS
SS returns the instrument operation status in three parts:
System Status (S), Current Fault(s) (F),
Holdover/GNSS (HO GNSS) Fault(s). The first set of numbers in each group indicate the current sta-
tus or fault, and the second set of numbers indicate what has changed. See Tables 11.1, 11.2, and 11.3 for
bit assignments of clock conditions. Note examples below.
S=60:60 F=0040:0040 HO GNSS=00
S=60:00 F=0040:0000 HO GNSS=00
In the two examples above, the first response indicates the first interrogation of clock status; the second
response follows the first and indicates no changes. “60” indicates that the Demo mode is active and the
clock is stabilized, “0040” indicates an antenna fault, and “00” indicates that there is no Holdover/GNSS
fault.
Time Quality
Command:
TQ
TQ returns a single ASCII character (0 – 9, A, B, F) indicating estimated worst-case time quality, which
follows the IEEE Standard, C37.118.1. Table 11.4 gives the returned value and error category.
Response: h
C
Value, h
Time Error
Value, h
Time Error
0
Locked, max. Accuracy
7
Unlocked, accuracy
<
1 ms
1
Unlocked, accuracy
<
1 ns
8
Unlocked, accuracy
<
10 ms
2
Unlocked, accuracy
<
10 ns
9
Unlocked, accuracy
<
100 ms
3
Unlocked, accuracy
<
100 ns
A
Unlocked, accuracy
<
1 s
4
Unlocked, accuracy
<
1 us
B
Unlocked, accuracy
<
10 s
5
Unlocked, accuracy
<
10 us
F
Clock failure
6
Unlocked, accuracy
<
100 us
–
–
Table 11.4: Unlocked Time Quality
Summary of Contents for 1201B
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