NavCom Sapphire Rev.J - Manual (Page 181)

Sapphire Technical Reference Manual Rev. J
181
1.126 PACKB
SF-3050 Sapphire SF-3040
This command is used to pack navigation corrections into the Sapphire command format. The
message follows standard binary format, with more header format descriptions provided in
paragraph 1.126.5.1. Issue the message whenever the sender accumulates 512 bytes of data
or when the time from the last transfer exceeds 500 ms
.
Table 75: PackB Command Format
Data Item Data Type Section
Format U08 1.126.1
Port U08 1.126.1
Correction Data U08[] 1.126.3
1.126.1 Format
Table 76: PackB Command Format Field Mnemonics
Format Field Value Meaning
0 Unknown
1 NCT proprietary
2 RTCM 2.3
3 RTCM 3.0
4 CMR/CMR+

Specifying the data format, although optional, can result in improved performance.
However, if the format field is set to Unknown and the data type is supported by the
receiver firmware, the correction data will be successfully sent and processed.
1.126.2 Port
This value is reserved; it is always 0.
1.126.3 Correction Data
This is actual correction data, up to 512 bytes. Each byte of the correction data is encoded by
being XORed with 0x55. The Sapphire parsers are highly adaptable. If correction data are not
encoded, the Sapphire parsers may become confused and start switching between correction
mode and Sapphire command mode. The receiver decoding function of the PACKB command
returns the data to their original values by XORing it with 0x55 again.
See example function (C#) below for building the PACKB message.
Private void SendCorrectionsOut( byte [] data, Uint16 len)
{
byte [] CorrectionsByteArray = new byte [2048];
// this is the data buffer plus the binary header
Uint16 Length = ( Uint16 )(len + 9 + 2);
// arbitrary gps week and time
Uint16 GPSWeek = 0x064A;
Uint32 GPSTime = (((2 * 24 + 8) * 60 * 60) + (15 * 60)) * 1000; // Tuesday,
8:15AM
byte TimeVersion = 0x00; // time is unknown; message version 0