Reference Manual Instruction Manual

669
Chapter 11. Data Output
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,<structure>
The message’s binary structure is described in the table
below.
Type*
Size
in bits
Resolution Contents
Unsigned short 16 Message length. Number of bytes in the <packed data> 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 <packed data>, after <message
length> and before <checksum>