LSF
Applicable to: UC6580, UM620 series, UM621 series, UM670A, UM680A, UM681A
Query Leap Seconds Forecast Information
| Syntax | $LSF,system | |
|---|---|---|
| Example | $LSF,1 | |
| Description | Query leap seconds forecast information of the specified satellite, and the receiver outputs LSF message after receiving the command |
|
| Input/Output | Input | |
| Parameter Definition | ||
| Parameter | Format | Description |
| system | UINT | Query the system corresponding to the leap seconds forecast information 0 - GPS 1 - BDS 2 - GLO 3 - GAL 4 - NavIC |
Output Leap Seconds Forecast Information
| Syntax | $LSF,system,flag,utcTLS,utcTLSF,utcTOT,utcWN,utcDN,utcWNLSF,utcA0,utcA1*cs | ||
|---|---|---|---|
| Example | $LSF,0,1,15,16,462836,82,6,86,7811626,14*5C | ||
| Description | Output leap seconds forecast information | ||
| Input/Output | Output | ||
| Parameter Definition | |||
| Parameter | Format | Description | |
| System | UINT | Output the system corresponding to the leap seconds forecast information 0 - GPS 1 - BDS 2 - GLO 3 - GAL 4 - NavIC |
|
| Flag | UINT | Validity flag of leap seconds forecast information 0 - Invalid 1 - Valid |
|
| utcTLS | UINT | Time difference between UTC and the system before a leap second event occurs; unit: s; GLO system does not have this parameter |
|
| utcTLSF | UINT | Time difference between UTC and the system after a leap second event occurs; unit: s; GLO system does not have this parameter |
|
| utcTOT | UINT | UTC reference seconds of week; unit: s (Fill 0 for BDS); GLO system: the parameter corresponds to GLO UTC A0 |
|
| utcWN | UINT | UTC reference week number; unit: week (Fill 0 for BDS); GLO system: the parameter corresponds to GLO UTC A1 |
|
| utcDN | UINT | Days of week when the leap second event occurs; unit: day; GLO system: the parameter corresponds to GLO UTC DN |
|
| utcWNLSF | UINT | UTC week number when the leap second event occurs; unit: week; GLO system: the parameter corresponds to GLO UTC KP |
|
| utcA0 | INT | Constant coefficient A0 of UTC polynomial (scale factor 2^-30); unit: s; GLO system: the parameter corresponds to GLO UTC tc |
|
| utcA1 | INT | First-order coefficient A1 of UTC polynomial (scale factor 2^-50); unit: s/s; GLO system: the parameter corresponds to GLO UTC tg |
|
| cs | U8 | Checksum; two hexadecimal characters obtained by calculating an XOR of all characters between but not including ‘$' to ‘*' in this message |
Note
GPS Week is the time system adopted in the GPS system. Time Zero is defined as: 00:00 on January 6,1980 and every 1024 weeks (7168 days) is a cycle. The first roll-over happened at 00:00:00 on August 22,1999. That is, from this moment on, the week number starts again from zero. In GPST, 1 to 7 corresponds to Sunday to Saturday.
The BDS time starts at 00:00:00 UTC on 1 January 2006, and uses week and day of week to count. 0 to 6 corresponds to Sunday to Saturday.
utcWNLSF: The decimal number converted from the binary lower eight bits of the week when a leap second occurs.
For example: A leap second occurred in the week 900 (binary: 1110000100), then the utcWNLSF broadcasts 132 (binary: 10000100).
Calculating the GPS week when a leap second occurs:
- Convert the RMC date into GPS week;
- Convert the GPS week into binary, set the lower eight bits to zero, and then convert to decimal.
- Add utcWNLSF to the number got from step 2.
Calculating the BDS week when a leap second occurs:
- Convert the RMC date into BDS week;
- Convert the BDS week into binary, set the lower eight bits to zero, and then convert to decimal.
- Add utcWNLSF to the number got from step 2.
utcDN: Day of week when a leap second occurs. GPS: 1 to 7 corresponding to Sunday to Saturday; BDS: 0 to 6 corresponding to Sunday to Saturday
Leap seconds occur at 23:59:59