gps-sem-parser
v1.1.4
Published
parser for GPS almanac .sem files
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Readme
gps-sem-parser
Example
import sem from 'gps-sem-parser';
const almanac = sem( rawAlmanac );
{
"gpsWeek": 1844,
"toa": 405504,
"epoch": 1115656704,
"satellites": [
{
"prn": 1,
"svn": 63,
"ura": 0,
"eccentricity": 0.00419855117797852,
"inclination": 0.9617664060621093,
"rightAscensionDot": -8.114623720935037e-9,
"semimajorAxis": 26559649.327529907,
"rightAscension": -1.6779199426606246,
"argumentOfPeriapsis": 0.37559459670255485,
"meanAnomaly": -2.781213528432701,
"clockBias": -0.0000057220458984375,
"clockDrift": 0,
"health": 0,
"config": 11
}
]
}
API
sem(file, gpsEpoch)
Parses a string containing a GPS almanac in sem format.
Pass gpsEpoch
with the number of times the gps week has rolled over.
Set gpsEpoch
to null
and year
to the year in which the almanac was issued to try to automatically resolve the gps epoch. (Defaults to current year)
Return an Almanac
object.
Parameters
| name | type | description |
| ---- | ---- | ----------- |
| file
| string
| Almanac in SEM format |
| gpsEpoch
| number
| (optional) Number of times the GPS Week index rolled over. |
| year
| number
| (optional) Year in which the Almanac was issued (to resolve gps epoch). ) |
Almanac
Object representing a GPS almanac
| name | type | description |
| ---- | ---- | ----------- |
| gpsWeek
| number
| GPS Week of the almanac |
| toa
| number
| Time of Applicability of the alamanc |
| epoch
| number
| Epoch of the almanac (seconds since start of GPS time) |
| satellites
| [Satellite]
| Array of satellite element sets |
Satellite
Object representing a satellite element set. (For details see IS-GPS-200)
| name | type | description |
| ---- | ---- | ----------- |
| prn
| number
| Assigned PRN |
| svn
| number
| Space Vehicle Number |
| ura
| number
| User Range Accuracy |
| eccentricity
| number
| Eccentricity at epoch |
| inclination
| number
| Inclination at epoch (rad) |
| rightAscensionDot
| number
| First derivative of the right ascension (rad/s) |
| semimajorAxis
| number
| Semimajor Axis at epoch (m) |
| rightAscension
| number
| Right ascension at start of GPS Week (rad) |
| argumentOfPeriapsis
| number
| Argument of periapsis (rad) |
| meanAnomaly
| number
| Mean Anomaly at epoch (rad) |
| clockBias
| number
| Clock bias at epoch (s) |
| clockDrift
| number
| Clock drift at epoch (s/s) |
| health
| number
| Health of satellite |
| config
| number
| Configuration of satellite |