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Diffstat (limited to 'tle.go')
| -rw-r--r-- | tle.go | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/tle.go b/tle.go new file mode 100644 index 0000000..95b0a55 --- /dev/null +++ b/tle.go @@ -0,0 +1,133 @@ +/* +Package tle implementing the "Two-line element set (TLE)", a data format encoding orbital elements of Earth-orbiting objects. + +More information can be found in the wikipedia article: (https://en.wikipedia.org/wiki/Two-line_element_set) and in the official NASA documentation: (https://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/SSOP_Help/tle_def.html) + +*/ +package tle + +// TLE defines the lines contained in a Two-Line-Element +type TLE struct { + TitleLine TitleLine `json:"titleline"` + LineOne LineOne `json:"lineone"` + LineTwo LineTwo `json:"linetwo"` +} + +// TitleLine defines the first line in the the TLE +// It contains the name of the satellite +type TitleLine struct { + Satname string `json:"satname"` +} + +// LineOne defines the first line in the TLE +type LineOne struct { + Linenumber int `json:"linenumber"` + + // Catalog number defined by USSPACECOM + // A "U" indicates an unclassified object + SatelliteNumber int `json:"satellitenumber"` + Classification string `json:"classification"` + + // International Designator containing information about the launch + InternationalDesignator InternationalDesignator `json:"internationaldesignator"` + + // Epoch defining from when the TLE is + Epoch Epoch `json:"epoch"` + + // First Time Derivative of the Mean Motion divided by two + // Unit: revs / day + // "catch all" drag term used in SGP4 USSPACECOM predictor + Firstderiv float64 `json:"firstderiv"` + + // Second Time Derivative of Mean Motion divided by six (decimal point assumed) + // second order drag term in the SGP4 + // Unit: revs / day^3 + // A leading decimal must be applied to this value + // The last two characters define an applicable power of 10 (12345-5 = 0.0000012345) + Secondderiv float64 `json:"secondderiv"` + + // Drag Term + // (67960-4 = 0.000067960) + // Unit: earth radii^-1 + // The last two characters define an applicable power of 10 + BSTAR float64 `json:"BSTAR"` + + // The number 0 (originally this should have been "Ephemeris type") + Numberzero int `json:"numberzero"` + + // Element set number. Incremented when a new TLE is generated for this object. + ElementSetNumber int `json:"elementesetnumber"` + + // Checksum (modulo 10) + Checksum int `json:"checksum"` +} + +// InternationalDesignator stores information about the satellite such as when it launched +type InternationalDesignator struct { + + // Last two digits of launch year + Launchyear int `json:"launchyear"` + + // Launch number of the year + Launchnumber int `json:"launchnumber"` + + // Piece of the launch + Launchpiece string `json:"launchpiece"` +} + +// Epoch defines a moment in time +type Epoch struct { + + // Last two digits of the year + Year int `json:"year"` + + // day of the year and fractional portion of the day + Dayfraction float64 `json:"dayfraction"` +} + +// LineTwo of the TLE +type LineTwo struct { + Linenumber int `json:"linenumber"` + + // Catalog number defined by USSPACECOM + SatelliteNumber int `json:"satellitenumber"` + + // Inclination + // Unit: degrees + // Angle between the equator and the orbit plane + Inclination float64 `json:"inclination"` + + // Right Ascension of the Ascending Node + // Unit: degrees + // Angle between vernal equinox and the point where the orbit crosses the equatorial plane (going north). + RightAscensionOfTheAscendingNode float64 `json:"rightascensionoftheascendingnode"` + + // Eccentricity + // Constant defining the shape of the orbit (0=circular, Less than 1=elliptical). + // The value provided is the mean eccentricity. + // A leading decimal must be applied to this value + Eccentricity float64 `json:"eccentricity"` + + // Argument of perigee + // Unit: degrees + // The angle between the ascending node and the orbit's point of closest approach of the earth (perigee) + ArgumentOfPerigee float64 `json:"argumentofperigee"` + + // Mean Anomaly + // Unit: degrees + // The angle, measured from perigee, of the satellite location in the orbit referenced to a circular orbit + // with radius equal to the semi-major axis. + MeanAnomaly float64 `json:"meananomaly"` + + // Mean Motion + // The value is the mean number of orbits per day the object completes. There are 8 digits after the decimal, + // leaving no trailing space(s) when the following element exceeds 9999. + MeanMotion float64 `json:"meanmotion"` + + // The orbit number at Epoch Time. This time is chosen very near the time of true ascending node passage as + // a matter of routine. The last digit is the check sum for line 2. + RevolutionNumberAtEpoch int `json:"revolutionnumberatepoch"` + + // Checksum (modulo 10) + Checksum int `json:"checksum"` +} |
