程序片段.txt

本程序所反应的是在测量中被广泛应用的全球定位系统（Global Position System）在空间中的形象以及基本的工作原理。GPS由三部分组成：空间部分、地面控制系统以及用户部分。

 x3d(1) = orbit * Sin(90 * pi / 180) * Cos(0)
 y3d(1) = orbit * Sin(90 * pi / 180) * Sin(0)
 z3d(1) = orbit * Cos(90 * pi / 180)
 
 linx = x3d(1)
 liny = y3d(1)
 linz = z3d(1)
 x3d(1) = linx * Cos(zzhuanjiao * pi / 180) - liny * Sin(zzhuanjiao * pi / 180)
 y3d(1) = linx * Sin(zzhuanjiao * pi / 180) + liny * Cos(zzhuanjiao * pi / 180)
 z3d(1) = linz
 
 linx = x3d(1)
 liny = y3d(1)
 linz = z3d(1)
 x3d(1) = linx
 y3d(1) = liny * Cos(qingjiao * pi / 180) + linz * Sin(qingjiao * pi / 180)
 z3d(1) = liny * Sin(qingjiao * pi / 180) - linz * Cos(qingjiao * pi / 180)
 x2d(1) = zbchangex(x3d(1), y3d(1), z3d(1), sita, fai, rou, d)
 y2d(1) = zbchangey(x3d(1), y3d(1), z3d(1), sita, fai, rou, d)
 For i = 0 To 360 Step 2
    x3d(2) = orbit * Sin(90 * pi / 180) * Cos(i * pi / 180)
    y3d(2) = orbit * Sin(90 * pi / 180) * Sin(i * pi / 180)
    z3d(2) = orbit * Cos(90 * pi / 180)
    
    linx = x3d(2)
    liny = y3d(2)
    linz = z3d(2)
    x3d(2) = linx * Cos(zzhuanjiao * pi / 180) - liny * Sin(zzhuanjiao * pi / 180)
    y3d(2) = linx * Sin(zzhuanjiao * pi / 180) + liny * Cos(zzhuanjiao * pi / 180)
    z3d(2) = linz
    
    linx = x3d(2)
    liny = y3d(2)
    linz = z3d(2)
    x3d(2) = linx
    y3d(2) = liny * Cos(qingjiao * pi / 180) + linz * Sin(qingjiao * pi / 180)
    z3d(2) = liny * Sin(qingjiao * pi / 180) - linz * Cos(qingjiao * pi / 180)
    x2d(2) = zbchangex(x3d(2), y3d(2), z3d(2), sita, fai, rou, d)
    y2d(2) = zbchangey(x3d(2), y3d(2), z3d(2), sita, fai, rou, d)
    Form1.Picture1.Line (x2d(1), y2d(1))-(x2d(2), y2d(2)), vbYellow
    x2d(1) = x2d(2)
    y2d(1) = y2d(2)
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