99 lines
2.2 KiB
Go
99 lines
2.2 KiB
Go
package calculator
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import (
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"math"
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"time"
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"github.com/hebl/gofa"
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)
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func ECItoECEF(j2000X, j2000Y, j2000Z float64, utc time.Time) (float64, float64, float64) {
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eci := [3]float64{j2000X, j2000Y, j2000Z}
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var ecef [3]float64
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// 当前的 TT 时间 (Terrestrial Time)
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var tt1, tt2 float64
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gofa.Dtf2d("UTC",
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utc.Year(),
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int(utc.Month()),
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utc.Day(),
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utc.Hour(),
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utc.Minute(),
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float64(utc.Second()),
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&tt1, &tt2)
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var djm0, mjd float64
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gofa.Cal2jd(int(utc.Year()), int(utc.Month()), int(utc.Day()), &djm0, &mjd)
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var dut1 float64 = 0.0562
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xp := 0.0
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yp := 0.0
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if e, ok := EOP.Get(mjd); ok {
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xp = e.Xp
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yp = e.Yp
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dut1 = e.Dut1
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}
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// 计算 UT1 时间 世界时UT1与协调世界时UTC
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var ut11, ut12 float64
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gofa.Utcut1(tt1, tt2, dut1, &ut11, &ut12)
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// 计算 C2T 矩阵 (ICRS -> CIRS -> ECEF)
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var rc2t [3][3]float64
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gofa.C2t06a(tt1, tt2, ut11, ut12, xp, yp, &rc2t)
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// 计算 ECEF 坐标
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gofa.Rxp(rc2t, eci, &ecef)
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return ecef[0], ecef[1], ecef[2]
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}
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func ECEFtoECI(X84, Y84, Z84 float64, utc time.Time) (float64, float64, float64) {
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ecef := [3]float64{X84, Y84, Z84}
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var eci [3]float64
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// 当前的 TT 时间 (Terrestrial Time)
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var tt1, tt2 float64
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gofa.Dtf2d("UTC",
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utc.Year(),
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int(utc.Month()),
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utc.Day(),
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utc.Hour(),
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utc.Minute(),
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float64(utc.Second()),
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&tt1, &tt2)
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var djm0, mjd float64
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gofa.Cal2jd(int(utc.Year()), int(utc.Month()), int(utc.Day()), &djm0, &mjd)
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var dut1 float64 = 0.0562
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xp := 0.0
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yp := 0.0
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if e, ok := EOP.Get(mjd); ok {
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xp = e.Xp
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yp = e.Yp
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dut1 = e.Dut1
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}
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// 计算 UT1 时间 世界时UT1与协调世界时UTC
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var ut11, ut12 float64
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gofa.Utcut1(tt1, tt2, dut1, &ut11, &ut12)
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// 计算 C2T 矩阵 (ICRS -> CIRS -> ECEF)
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var rc2t [3][3]float64
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gofa.C2t06a(tt1, tt2, ut11, ut12, xp, yp, &rc2t)
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// 计算 ECEF 到 ECI 的转换矩阵
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var rc2tT [3][3]float64
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gofa.Tr(rc2t, &rc2tT)
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// 将 ECEF 坐标转换为 ECI 坐标
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gofa.Rxp(rc2tT, ecef, &eci)
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return eci[0], eci[1], eci[2]
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}
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func ECEFGeocentricToGeodetic(x, y, z float64) (float64, float64, float64) {
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var lat, lon, alt float64
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gofa.Gc2gd(gofa.WGS84, [3]float64{x, y, z}, &lon, &lat, &alt)
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return lat * 180 / math.Pi, lon * 180 / math.Pi, alt
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}
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