User's Manual

SPSx80 and SPSx81 Smart GPS Antennas User Guide 101
GSOF Messages B
DOUBLE
The DOUBLE data type is stored in the IEEE double-precision format which is 64 bits
long. The most significant bit is the sign bit, the next 11 most significant bits are the
exponent field, and the remaining 52 bits are the fractional field. The bias of the
exponent is 1023. The range of single precision format values is from 2.23
× 10
–308
to
1.8
× 10
308
. The floating-point number is precise to 15 decimal digits.
0 000 0000 0000 0000 0000 ... 0000 0000 0000 = 0.0
0 011 1111 1111 0000 0000 ... 0000 0000 0000 = 1.0
1 011 1111 1110 0110 0000 ... 0000 0000 0000 = -0.6875
1 111 1111 1111 1111 1111 ... 1111 1111 1111 = NaN
GSOF message definitions
When GSOF output is enabled, the following messages can be generated.
TIME
This message describes position time information. It contains the following data:
• GPS time, in milliseconds of GPS week
• GPS week number
• Number of satellites used
• Initialization counter
Table B.3 Time (Type 1 record)
Field Item Type Value Meaning
0 Output record type Char 01h Position time output record
1 Record length Char 0Ah Bytes in record
2–5 GPS time (ms) Long msecs GPS time, in milliseconds of GPS week
6–7 GPS week number Short number GPS week count since January 1980
8 Number of SVs used Char 00h-0Ch Number of satellites used to determine the
position (0-12)
9 Position flags 1 Char See Table B.16 Reports first set of position attribute flag
values
10 Position flags 2 Char See
Table B.17 Reports second set of position attribute flag
values
11 Initialized number Char 00h-FFh Increments with each initialization (modulo
256)
S Exp. + Bias Fraction
63 62 52
51 0