Spectra Precision ProMark 800 Reference Manual - Manual (Page 405)

393
Output Message Library
DPC: Compact GPS Measurements
This message contains the L1/L2 measurements from all
tracked GPS satellites for one epoch.
The message is as follows:
$PASHR,DPC,
The message’s binary structure is described in the table
below.
The data in this message are packed in bits rather than bytes.
So the presented types of fields are just for the sake of giving
a meaningful description of the original data packing.
NOTES:
Type*
Size
in bits
Resolution Contents
Unsigned short 16 Message length. Number of bytes in the section.
PACKED DATA
Double
32 1 msec Receiver time in GPS milliseconds of week
Char[4] 32 Receiver’s four-character ID
Unsigned long 32
Mask representing satellites that are contributors to the message content.
This is a bitwise indication: Starting from the least significant bit, bit1 cor-
responds to SV PRN#1, bit2 corresponds to SV PRN#2, and so on.
Bit value “1” for a given SV PRN means the corresponding satellite is a
data contributor to this message, “0” otherwise.
The data that follow are repeated for each satellite presented in the satellite mask
Unsigned char 1
Satellite health (“0” means Sat is unhealthy)
Unsigned char 7 1 degree Satellite elevation
Unsigned char 1 RAIM status (always zero)
Unsigned char 7 1 dBHz SNR of L1CA observation
#L1 Data Block (L1CA in all cases)
Double 31 0.1 nsec
Raw range in 0.1 nsec (range is smoothed by carrier). “0” means bad raw
range data.
Unsigned char 1 Warning flag (“1” means bad carrier phase with possible cycle slips)
Unsigned char 1 Sign of total carrier phase (“1”: negative; “0”:positive)
Double 28 1 cycle Integer part of total carrier phase in cycles
Double 11 0.0005 cycles Fractional part of phase in 0.0005 cycles
Double 24 0.002 Hz Doppler in units of 0.002 Hz
#L2 Data Block (L2P for CFG,2&4 and L2C for CFG,3&5)
Content and data packing scheme is the same as for L1 Data
CHECKSUM
Unsigned short 16
Cumulative unsigned short sum of the , after length> and before