apsis-book/content/flows/frame-rotation.json

205 lines
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{
"id": "frame-rotation",
"title": "Frame rotation and geodetic conversion",
"summary": "The two transformations between the representations of a position: the Cartesian rotation about the pole, and the ellipsoidal conversion.",
"nodes": [
{
"id": "angle",
"label": "Earth Rotation Angle from UT1",
"kind": "data",
"group": "input",
"summary": "A linear function of the days of UT1 since J2000.0, in turns.",
"api": "EarthRotationAngle",
"label_zh": "由 UT1 求地球自转角",
"summary_zh": "自 J2000.0 起 UT1 天数的线性函数,单位为圈。"
},
{
"id": "eci",
"label": "Eci",
"kind": "data",
"group": "frames",
"summary": "A Cartesian position in the inertial frame, in meters.",
"api": "Eci",
"summary_zh": "惯性系中的直角坐标位置,单位为米。"
},
{
"id": "ecef",
"label": "Ecef",
"kind": "data",
"group": "frames",
"summary": "A Cartesian position in the Earth-fixed frame, in meters.",
"api": "Ecef",
"summary_zh": "地固系中的直角坐标位置,单位为米。"
},
{
"id": "matrix",
"label": "Build the rotation matrix",
"kind": "step",
"group": "rotate",
"summary": "A clockwise turn about the third axis, whose transpose is the inverse.",
"api": "rotation_eci_to_ecef",
"label_zh": "构造旋转矩阵",
"summary_zh": "绕第三轴的顺时针转动,其转置即逆变换。"
},
{
"id": "to_ecef",
"label": "Rotate inertial to Earth-fixed",
"kind": "step",
"group": "rotate",
"summary": "Apply the rotation to the vector. The length is preserved.",
"api": "Eci",
"label_zh": "惯性系旋转到地固系",
"summary_zh": "对矢量施加旋转。长度保持不变。"
},
{
"id": "to_eci",
"label": "Rotate Earth-fixed to inertial",
"kind": "step",
"group": "rotate",
"summary": "Apply the transposed rotation. The length is preserved.",
"api": "Ecef",
"label_zh": "地固系旋转到惯性系",
"summary_zh": "施加转置后的旋转。长度保持不变。"
},
{
"id": "cartesian",
"label": "Cartesian to geodetic",
"kind": "step",
"group": "geodetic",
"summary": "Solve for latitude, longitude, and height on an ellipsoid. Iterative, because no elementary closed form exists.",
"api": "geodetic_from_cartesian",
"label_zh": "直角坐标转大地坐标",
"summary_zh": "在椭球上求解纬度、经度与高。因无初等闭式解而采用迭代。"
},
{
"id": "polar",
"label": "On the rotation axis?",
"kind": "decision",
"group": "geodetic",
"summary": "No longitude is defined on the axis.",
"label_zh": "位于自转轴上?",
"summary_zh": "轴上经度无定义。"
},
{
"id": "undefined",
"label": "No longitude",
"kind": "terminal",
"group": "error",
"summary": "The conversion returns no value rather than an arbitrary longitude.",
"label_zh": "经度无定义",
"summary_zh": "转换返回空值,而不是任意经度。"
},
{
"id": "geodetic",
"label": "Geodetic",
"kind": "terminal",
"group": "output",
"summary": "Latitude and longitude in radians, height in meters above the WGS 84 ellipsoid.",
"api": "Geodetic",
"summary_zh": "纬度与经度单位为弧度,高为 WGS 84 椭球面以上的米数。"
},
{
"id": "forward",
"label": "Geodetic to Cartesian",
"kind": "step",
"group": "geodetic",
"summary": "Closed form, using the prime vertical radius of curvature.",
"api": "cartesian_from_geodetic",
"label_zh": "大地坐标转直角坐标",
"summary_zh": "闭式解,使用卯酉圈曲率半径。"
},
{
"id": "direct",
"label": "Geodetic to Ecef",
"kind": "terminal",
"group": "output",
"summary": "The Earth-fixed Cartesian position on the WGS 84 ellipsoid.",
"api": "Geodetic",
"label_zh": "大地坐标转 Ecef",
"summary_zh": "WGS 84 椭球上的地固系直角坐标。"
}
],
"edges": [
{
"source": "angle",
"target": "matrix",
"kind": "flow",
"label": null
},
{
"source": "matrix",
"target": "to_ecef",
"kind": "flow",
"label": null
},
{
"source": "matrix",
"target": "to_eci",
"kind": "flow",
"label": null
},
{
"source": "eci",
"target": "to_ecef",
"kind": "flow",
"label": null
},
{
"source": "ecef",
"target": "to_eci",
"kind": "flow",
"label": null
},
{
"source": "to_ecef",
"target": "ecef",
"kind": "flow",
"label": "Earth-fixed"
},
{
"source": "to_eci",
"target": "eci",
"kind": "flow",
"label": "inertial"
},
{
"source": "to_ecef",
"target": "cartesian",
"kind": "flow",
"label": null
},
{
"source": "cartesian",
"target": "polar",
"kind": "flow",
"label": null
},
{
"source": "polar",
"target": "undefined",
"kind": "branch",
"label": "yes"
},
{
"source": "polar",
"target": "geodetic",
"kind": "branch",
"label": "no"
},
{
"source": "geodetic",
"target": "forward",
"kind": "flow",
"label": null
},
{
"source": "forward",
"target": "direct",
"kind": "flow",
"label": null
}
],
"title_zh": "参考系旋转与大地坐标转换",
"summary_zh": "位置各表示之间的两种变换:绕极轴的直角坐标旋转,以及椭球坐标转换。"
}