Signal Information (Sub ID 0x0FE)
Applicable to: UC6580, UM670A, UM680A
The message Signal Information contains parameters related to satellite status, including PRN, CN0, elevation, azimuth and pseudo-range residual etc. If there is no GNSS signal, the message outputs the header and the field SatNum = 0. The data transmission uses Big Endian method. See the following tables for the details of the message structure.
| ID | Field | Type | Description | Bytes | Byte Offset |
|---|---|---|---|---|---|
| 1 | Version | U8 | Protocol version | 1 | 0 |
| 2 | Week | U16 | GPS week, starting from Jan. 6th 1980; 0xFFFF means invalid |
2 | 1 |
| 3 | Tow | U32 | GPS time of week; unit: ms; 0xFFFFFFFF means invalid |
4 | 3 |
| 4 | SatNum | U32 | Repeat time of satellite status | 4 | 7 |
| 5 | SatInfo | — | See the table below for details | SatNum*(8 + 6*Nf) | 11 |
| Total | 11+SatNum*(8 + 6*Nf) |
The table below shows the encoding structure of satellite information.
| ID | Field | Type | Description | Bytes | Byte Offset |
|---|---|---|---|---|---|
| 1 | Prn | U8 | Satellite number: GPS 01 to 32 QZSS 01 to 10 GLO 65 to 99 BDS 01 to 64 GAL 01 to 36 SBAS 33 to 51 |
1 | 0 |
| 2 | System | U8 | 1 - GPS 2 - GLO 3 - GAL 4 - BDS 5 - QZSS 6 - SBAS |
1 | 1 |
| 3 | El | U16 | Satellite elevation; unit: 1e-1 deg; range: 0 to 900; 0xFFFF means invalid |
2 | 2 |
| 4 | Az | U16 | Satellite azimuth; unit: 1e-1 deg; range: 0 to 3600; 0xFFFF means invalid |
2 | 4 |
| 5 | InUse | U8 | 0 - not used in positioning 1 - used in positioning |
1 | 6 |
| 6 | Freq Num (Nf) | U8 | The frequency number of the satellite | 1 | 7 |
| Field 7 to 10 repeat Nf times (see Field 6) | |||||
| 7 | Freq ID | U8 | GPS: 2 - GPS L1C/A 16 - GPS L2C(L) 23 - GPS L5Q GLO: 2 - G1C/A BDS: 2 - B1I 14 - B2I 23 - B2a_pilot GAL: 2 - E1C no data 15 - E5bQ 23 - E5aQ QZSS: 2 - QZSS L1C/A 16 - QZSS L2C(L) 23 - QZSS L5Q SBAS: 2 - SBAS L1C/A 23 - SBAS L5Q |
1 | 2 + 6*Nf |
| 8 | CN0 | U8 | Unit: dB.Hz | 1 | 3 + 6*Nf |
| 9 | PrResi | U16 | Positioning pseudo-range residual of each satellite; unit: 1e-1 m; 0xFFFF means invalid |
2 | 4 + 6*Nf |
| 10 | DpResi | U16 | Velocity measurement Doppler residual of each satellite; unit: 1e-1 Hz; 0xFFFF means invalid |
2 | 6 + 6*Nf |
| Total | 8 + 6*Nf |