Berkeley Varitronics Systems Fox Manual page 41

There are three components of data in the satellite range data messagv (Carrier Phase Data, Smoothed Satellite Time data, and
RAW Code Phaseand Code Discriminator Data) shown in the following table.
Three Components of Satellite Range Data Message
DATA CONTAINED IN SAT OPTION OPTION OPTION
RANGE MSG
Raw Code Phase & Disc yes
Data
Smooth Sat Time Data
Carrier Phase Data
The same format for the satellite range data message applies to all three options. The data fields that are not available in the
Options are zero filled.
Input/Output Processing Time
The receiver operates in two modes: idle and position fix. When the receiver is in the idle mode, no satellites are being tracked,
and only the last known receiver position is available. When the receiver is in the position fix mode, satellites are being tracked,
and the current receiver position is available. In the idle mode, the receiver processes input buffer data as soon as a full com-
mand has been detected. In the position fix mode, the input buffer data is serviced once a second.
The message response time will be the time from the transmission of the first byte of input data to the transmission of the last
byte of output data. For the idle mode, assuming 1 ms per transmission of a data byte, and assuming 50 ms command process-
ing, the best case and worst case scenarios follow.
Best Case (Idle): Delete all waypoints
Thci= shortest command input + command processing +
shortest command output
= 7ms + 50 ms + 7 ms
= 64 ms
Worst Case (Idle): Output route
Twci= longest command input + command processing + longest command output
= 21 ms + 50 ms + 377 ms
= 448 ms
Input/Output Processing Time(Cont) In the position fix mode, the command processing time will be skewed since the time will be
dependent on when the input message buffer is processed. For best case processing, the input command would have to arrive
just before the input buffer data is processed, and the output response would have to be the first (or oniv) receiver output. For
worst case processing, the input command would have to arrive just after the input buffer data had been processed, and the
output response would have to be the last receiver output. Assuming 1 ms per transmission of a data byte, assuming 50 ms
command processing, and assuming a uniform distribution for time of input command data entry, the best case, typical case,
and worst case scenarios are shown below.
Best Case (Position Fix): Delete all waypoints
Tbcf= shortest command input + command processing +
shortest command output
= 7 ms + 50 ms + 7 ms
= 64 ms
Typical Case (Position Fix): Any command
yes yes
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