SinWBD = 0.913252512172146
解之得：
WB = 37229993.55877m
③ 计算光从卫星传到西安的距离：
当光从卫星发射时，西安用 表示，卫星与地心连线穿过地面点为C ；当光传到西安时，西安随地球自转
A
A
到达了
。
A
的坐标为：
X = RCos(w) Cos( j) = RCos34.370 Cos109.220530
A
= −0.271728845053R
Y = RCos(w)Sin( j) = RCos34.370 Sin109.220530
A
= 0.779399630600R
Z = RSin(w) = RSin34.37 = 0.564534897583R
A
则
A C 的长度（弦长）为：
Xw = RCos(w)Cos( j) = RCos0Cos148 = −0.848048096156426R
Yw = RCos(w)Sin( j) = RCos0Sin148 = 0.529919264233205R
Zw = RSin(w) = RSin0 = 0
2
2
2
A C = (X − X ) +(Y −Y ) +(Z −Z )
A
A
A
c
c
c
(−0.8480480962R − X )2 +(0.5299192642R −Y )2 +(0 −Z )2
A
A
A
=
=5379946.36332m
2
2
2
OA +OC − A C
0
A C 所对应的圆心角为
：
A OC = arcCos(
) = 49.9498395
2OA OC
125