sgp4go/surface_test.go at main · morphism/sgp4go · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
package sgp4go

import (
	"fmt"
	"strings"
	"testing"
	"time"
)

func BenchmarkProp(b *testing.B) {
	var (
		ms       = time.Now().UTC().UnixNano() / 1000 / 1000 // ToDo: Use constant.
		line1    = "1 39132U PLANET   20016.08334491  .00000000  00000+0 -47542-3 0    07"
		line2    = "2 39132 064.8760 163.6520 0036285 284.0373 175.5769 15.07452065    00"
		tle, err = NewTLE(line1, line2)
	)

	if err != nil {
		b.Fatal(err)
	}

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		r, v, err := tle.PropUnixMillis(ms)
		if err != nil {
			b.Fatal(err)
		}
		if r[0] == 0 {
			b.Fatal(r)
		}
		if v[0] == 0 {
			b.Fatal(v)
		}
	}
}

var ISS = `ISS (ZARYA)
1 25544U 98067A   20349.28181795  .00001103  00000-0  27992-4 0  9997
2 25544  51.6443 177.3570 0001731 128.2351  43.6939 15.49184106259930`

func Example() {
	var (
		tle = ISS

		lines = strings.Split(tle, "\n")
		o, _  = NewTLE(lines[1], lines[2])
		then  = "2020-12-12T12:00:00.000Z"
		t0, _ = time.Parse(time.RFC3339Nano, then)

		e, _ = o.Prop(t0)
	)

	fmt.Printf("%#v", e)

	// Output:
	// sgp4go.Ephemeris{V:sgp4go.Vect{X:-5.677866567405847, Y:-3.554868601056742, Z:3.696844342787944}, ECI:sgp4go.Vect{X:-4522.507182662008, Y:2857.518282965092, Z:-4201.949004177315}}
}

func getExample(t *testing.T) *TLE {
	var (
		tle = `ISS (ZARYA)
1 25544U 98067A   20349.28181795  .00001103  00000-0  27992-4 0  9997
2 25544  51.6443 177.3570 0001731 128.2351  43.6939 15.49184106259930`

		lines = strings.Split(tle, "\n")
		o, err  = NewTLE(lines[1], lines[2])
	)

	if err != nil {
		t.Fatal(err)
	}

	return o
}

func TestSemiMajorAxis(t *testing.T) {
	var (
		alt = 408.0
		earthRadius = 6371.0
		want = alt + earthRadius
		o = getExample(t)
		m = o.SemiMajorAxisMeters()
		got = m / 1000
		epsilon = 20.0 // km
	)

	if  got < want - epsilon || want + epsilon < got {
		t.Fatal(got -want)
	}
}

func TestLines(t *testing.T) {
	var (
		tle = ISS
		lines = strings.Split(tle, "\n")
		o, err  = NewTLE(lines[1], lines[2])
	)

	if err != nil {
		t.Fatal(err)
	}
	line1, line2 := o.Lines()

	if line1 != lines[1] {
		t.Fatal(line1)
	}

	if line2 != lines[2] {
		t.Fatal(line2)
	}
}

func TestEqual(t *testing.T) {
	var (
		x = getExample(t)
		y = getExample(t)
	)

	t.Run("same", func(t *testing.T) {
		if !x.EqualValues(y) {
			t.Fatal(false)
		}
	})

	t.Run("different", func(t *testing.T) {
		y.epoch++
		if x.EqualValues(y) {
			t.Fatal(true)
		}
	})
}