Gps-sem-parser NPM

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