The 1 PPS output is a TTL or RS-422 pulse that rises on the UTC or GPS time second boundary. Message 0x0019 provides the offset between the actual pulse edge and the theoretical second, enabling sub‑microsecond synchronization. This is critical for:
| Feature | ICD-GPS-153 | NMEA 0183 | |---------|-------------|-----------| | Format | Binary | ASCII | | Update rate | Up to 20 Hz | Typically 1 Hz (max 5–10 Hz) | | Checksum | 16-bit CRC | XOR of characters | | Precision | 1e-7 degrees (cm level) | 1e-4 degrees (meter level) | | Raw measurements | Yes (carrier phase) | No | | Military P(Y) code | Supported | No | | Host‑initiated commands | Extensive | Limited | icd-gps-153 protocol
A bitmask of PRN numbers indicating which satellites are tracked and used in the solution. The 1 PPS output is a TTL or
Breakdown:
: Configured for ICD-GPS-153 for secondary timing synchronization. Breakdown: : Configured for ICD-GPS-153 for secondary timing