{
  "id": "concepts",
  "title": "Concept map",
  "summary": "The concepts of the ApsisRS kernels and the relationships between them. Each node opens the document that explains it.",
  "nodes": [
    {
      "id": "overview",
      "label": "Concept overview",
      "kind": "concept",
      "group": "overview",
      "summary": "Scope and reading order of the concept set.",
      "document": "overview",
      "label_zh": "概念总览",
      "summary_zh": "概念集的覆盖范围与阅读顺序。"
    },
    {
      "id": "architecture-apsis-rs",
      "label": "Workspace architecture",
      "kind": "concept",
      "group": "overview",
      "summary": "The layer order and the crates in each layer.",
      "document": "architecture-apsis-rs",
      "label_zh": "工作区架构",
      "summary_zh": "分层顺序及每层的 crate。"
    },
    {
      "id": "standards-and-provenance",
      "label": "Standards and provenance",
      "kind": "concept",
      "group": "overview",
      "summary": "The public sources each algorithm follows.",
      "document": "standards-and-provenance",
      "label_zh": "标准与来源",
      "summary_zh": "各算法遵循的公开来源。"
    },
    {
      "id": "time-scales",
      "label": "Time scales",
      "kind": "concept",
      "group": "time",
      "summary": "UTC, TAI, TT, and GPS, and the storage convention.",
      "document": "time-scales",
      "label_zh": "时间尺度",
      "summary_zh": "UTC、TAI、TT 与 GPS，以及存储约定。"
    },
    {
      "id": "leap-seconds",
      "label": "Leap seconds",
      "kind": "concept",
      "group": "time",
      "summary": "The step discontinuities in UTC and the embedded table.",
      "document": "leap-seconds",
      "label_zh": "闰秒",
      "summary_zh": "UTC 中的阶跃间断与内嵌闰秒表。"
    },
    {
      "id": "calendar-and-mjd",
      "label": "Calendars and MJD",
      "kind": "concept",
      "group": "time",
      "summary": "Day numbering and the proleptic Gregorian calendar.",
      "document": "calendar-and-mjd",
      "label_zh": "日历与 MJD",
      "summary_zh": "日编号与外推格里高利历。"
    },
    {
      "id": "reference-frames",
      "label": "Reference frames",
      "kind": "concept",
      "group": "geometry",
      "summary": "Inertial, Earth-fixed, and geodetic frames.",
      "document": "reference-frames",
      "label_zh": "参考系",
      "summary_zh": "惯性系、地固系与大地坐标。"
    },
    {
      "id": "earth-rotation-angle",
      "label": "Earth Rotation Angle",
      "kind": "concept",
      "group": "geometry",
      "summary": "The angle that relates the two Cartesian frames.",
      "document": "earth-rotation-angle",
      "label_zh": "地球自转角",
      "summary_zh": "联系两个直角坐标系的夹角。"
    },
    {
      "id": "geodesy-wgs84",
      "label": "WGS 84 and geodetic coordinates",
      "kind": "concept",
      "group": "geometry",
      "summary": "Latitude, longitude, height, and the Cartesian conversion.",
      "document": "geodesy-wgs84",
      "label_zh": "WGS 84 与大地坐标",
      "summary_zh": "纬度、经度、高与直角坐标转换。"
    },
    {
      "id": "tle-format",
      "label": "Two-line element format",
      "kind": "data",
      "group": "elements",
      "summary": "The fixed width element record and its checksum.",
      "document": "tle-format",
      "label_zh": "两行元素格式",
      "summary_zh": "定宽元素记录及其校验和。"
    },
    {
      "id": "keplerian-elements",
      "label": "Keplerian elements",
      "kind": "concept",
      "group": "elements",
      "summary": "The six classical elements and the two-body solution.",
      "document": "keplerian-elements",
      "label_zh": "开普勒轨道元素",
      "summary_zh": "六个经典元素与二体解。"
    },
    {
      "id": "sgp4",
      "label": "SGP4 and SDP4",
      "kind": "concept",
      "group": "propagation",
      "summary": "The analytical propagator the element sets are fitted to.",
      "document": "sgp4",
      "label_zh": "SGP4 与 SDP4",
      "summary_zh": "元素集所拟合的解析传播器。"
    },
    {
      "id": "perturbations",
      "label": "Orbital perturbations",
      "kind": "concept",
      "group": "propagation",
      "summary": "The forces that make an orbit deviate from an ellipse.",
      "document": "perturbations",
      "label_zh": "轨道摄动",
      "summary_zh": "使轨道偏离椭圆的各种力。"
    },
    {
      "id": "propagator-comparison",
      "label": "Choosing a propagator",
      "kind": "concept",
      "group": "propagation",
      "summary": "The propagation methods compared by accuracy and cost.",
      "document": "propagator-comparison",
      "label_zh": "传播器选择",
      "summary_zh": "各传播方法按精度与开销对比。"
    },
    {
      "id": "ephemeris-interpolation",
      "label": "Ephemeris interpolation",
      "kind": "concept",
      "group": "propagation",
      "summary": "Sampling a track once and querying it by interpolation.",
      "document": "ephemeris-interpolation",
      "label_zh": "星历插值",
      "summary_zh": "采样一次并按插值查询。"
    },
    {
      "id": "method-hpop",
      "label": "HPOP",
      "kind": "concept",
      "group": "methods",
      "summary": "Numerical integration of a high order force model. Not implemented in apsis-rs.",
      "document": "propagator-comparison",
      "summary_zh": "高阶力模型的数值积分。apsis-rs 未实现。"
    },
    {
      "id": "method-numerical",
      "label": "Numerical integration",
      "kind": "concept",
      "group": "methods",
      "summary": "Integrating the equations of motion from a force model. Not implemented in apsis-rs.",
      "document": "propagator-comparison",
      "label_zh": "数值积分",
      "summary_zh": "由力模型积分运动方程。apsis-rs 未实现。"
    },
    {
      "id": "method-two-body",
      "label": "Two-body propagation",
      "kind": "concept",
      "group": "methods",
      "summary": "The closed form Keplerian solution. Implemented as apsis-kepler.",
      "document": "keplerian-elements",
      "label_zh": "二体传播",
      "summary_zh": "开普勒闭式解。实现为 apsis-kepler。"
    },
    {
      "id": "crate-apsis-time",
      "label": "apsis-time",
      "kind": "crate",
      "group": "time",
      "summary": "Time scales, epochs, and calendar conversions.",
      "document": "time-scales",
      "api": "Epoch",
      "summary_zh": "时间尺度、历元与日历转换。"
    },
    {
      "id": "crate-apsis-coord",
      "label": "apsis-coord",
      "kind": "crate",
      "group": "geometry",
      "summary": "Positions that carry their reference frame in the type.",
      "document": "reference-frames",
      "api": "Eci",
      "summary_zh": "在类型中携带参考系的位置表示。"
    },
    {
      "id": "crate-apsis-sgp4",
      "label": "apsis-sgp4",
      "kind": "crate",
      "group": "propagation",
      "summary": "The SGP4 and SDP4 analytical orbit propagator.",
      "document": "sgp4",
      "api": "Satellite",
      "summary_zh": "SGP4 与 SDP4 解析轨道传播器。"
    },
    {
      "id": "units-and-dimensions",
      "label": "Units and dimensions",
      "label_zh": "量纲与单位",
      "kind": "concept",
      "group": "foundation",
      "summary": "How a physical quantity carries its unit, and the conventions that make an answer interpretable.",
      "summary_zh": "物理量如何携带单位，以及让结果可解释的约定。",
      "document": "units-and-dimensions"
    },
    {
      "id": "numerical-methods",
      "label": "Numerical method",
      "label_zh": "数值方法与误差",
      "kind": "concept",
      "group": "foundation",
      "summary": "Being wrong, being imprecise, and being unstable are three different things.",
      "summary_zh": "算错、不够精确、不稳定是三件不同的事。",
      "document": "numerical-methods"
    },
    {
      "id": "maneuvers",
      "label": "Orbit manoeuvres",
      "label_zh": "轨道机动",
      "kind": "concept",
      "group": "orbit",
      "summary": "Changing an orbit, what it costs, and why the cheapest transfer is the usual one.",
      "summary_zh": "改变轨道、代价几何，以及为什么最省的转移是通常那条。",
      "document": "maneuvers"
    },
    {
      "id": "higher-order-gravity",
      "label": "Higher order gravity",
      "label_zh": "高阶引力",
      "kind": "concept",
      "group": "orbit",
      "summary": "The expansion of the gravity field, and where it converges slowly.",
      "summary_zh": "引力场的展开，以及它在何处收敛缓慢。",
      "document": "higher-order-gravity"
    },
    {
      "id": "solar-radiation-pressure",
      "label": "Solar radiation pressure",
      "label_zh": "太阳光压",
      "kind": "concept",
      "group": "orbit",
      "summary": "Photon momentum on a sunlit surface, and why it shapes a constellation.",
      "summary_zh": "受照表面的光子动量，以及它如何塑造星座。",
      "document": "solar-radiation-pressure"
    },
    {
      "id": "atmospheric-drag",
      "label": "Atmospheric drag",
      "label_zh": "大气阻力与密度模型",
      "kind": "concept",
      "group": "orbit",
      "summary": "The density model, and why the hardest altitude is the one that matters.",
      "summary_zh": "密度模型，以及为什么最难的恰是最要紧的高度。",
      "document": "atmospheric-drag"
    },
    {
      "id": "doppler-and-rate",
      "label": "Doppler and range rate",
      "label_zh": "多普勒频移与测距率",
      "kind": "concept",
      "group": "rf",
      "summary": "How motion changes the received frequency, and how that becomes a position.",
      "summary_zh": "运动如何改变接收频率，以及该频率如何成为位置。",
      "document": "doppler-and-rate"
    },
    {
      "id": "link-budget",
      "label": "Link budget",
      "label_zh": "链路预算",
      "kind": "concept",
      "group": "rf",
      "summary": "The arithmetic of whether a signal arrives strong enough to be used.",
      "summary_zh": "信号是否强到可用的算术。",
      "document": "link-budget"
    },
    {
      "id": "atmospheric-propagation",
      "label": "Atmospheric propagation",
      "label_zh": "大气传播",
      "kind": "concept",
      "group": "rf",
      "summary": "What the air between satellite and receiver does to the signal.",
      "summary_zh": "卫星与接收机之间的空气对信号做了什么。",
      "document": "atmospheric-propagation"
    },
    {
      "id": "interference",
      "label": "Interference",
      "label_zh": "干扰",
      "kind": "concept",
      "group": "rf",
      "summary": "Noise degrades a measurement; a coherent source replaces it.",
      "summary_zh": "噪声使测量劣化，相干源则替换它。",
      "document": "interference"
    },
    {
      "id": "constellations",
      "label": "Constellations",
      "label_zh": "星座与覆盖",
      "kind": "concept",
      "group": "network",
      "summary": "Planes, phasing and shell, and what the arithmetic forces.",
      "summary_zh": "轨道面、相位与壳层，以及该算术强制了什么。",
      "document": "constellations"
    },
    {
      "id": "access-and-availability",
      "label": "Visibility and access",
      "label_zh": "可见性与接入",
      "kind": "concept",
      "group": "network",
      "summary": "The difference between overhead and usable.",
      "summary_zh": "在头顶与能用之间的差别。",
      "document": "access-and-availability"
    },
    {
      "id": "handover-and-routing",
      "label": "Topology and handover",
      "label_zh": "拓扑、切换与路由",
      "kind": "concept",
      "group": "network",
      "summary": "Which way across a network whose nodes move.",
      "summary_zh": "节点在动的网络上选哪条路。",
      "document": "handover-and-routing"
    },
    {
      "id": "tt-and-c",
      "label": "Telemetry, tracking and command",
      "label_zh": "遥测、跟踪与遥控",
      "kind": "concept",
      "group": "ops",
      "summary": "The chain that turns a spacecraft into something flyable.",
      "summary_zh": "把航天器变成可飞行之物的链路。",
      "document": "tt-and-c"
    },
    {
      "id": "operations-planning",
      "label": "Operations planning",
      "label_zh": "运行规划",
      "kind": "concept",
      "group": "ops",
      "summary": "Allocating fuel, contact and safety across a mission.",
      "summary_zh": "在燃料、接触与安全之间做分配。",
      "document": "operations-planning"
    },
    {
      "id": "scenario-simulation",
      "label": "Scenario and event simulation",
      "label_zh": "场景与事件仿真",
      "kind": "concept",
      "group": "sim",
      "summary": "What a simulation establishes, and what it does not.",
      "summary_zh": "仿效能确立什么、不能确立什么。",
      "document": "scenario-simulation"
    }
  ],
  "edges": [
    {
      "source": "overview",
      "target": "architecture-apsis-rs",
      "kind": "explains",
      "label": "structure"
    },
    {
      "source": "overview",
      "target": "standards-and-provenance",
      "kind": "explains",
      "label": "sources"
    },
    {
      "source": "time-scales",
      "target": "leap-seconds",
      "kind": "uses",
      "label": "UTC offset"
    },
    {
      "source": "time-scales",
      "target": "calendar-and-mjd",
      "kind": "uses",
      "label": "date display"
    },
    {
      "source": "leap-seconds",
      "target": "calendar-and-mjd",
      "kind": "relates",
      "label": "inserted seconds"
    },
    {
      "source": "reference-frames",
      "target": "earth-rotation-angle",
      "kind": "uses",
      "label": "rotation"
    },
    {
      "source": "reference-frames",
      "target": "geodesy-wgs84",
      "kind": "uses",
      "label": "ellipsoid"
    },
    {
      "source": "earth-rotation-angle",
      "target": "calendar-and-mjd",
      "kind": "uses",
      "label": "days since J2000"
    },
    {
      "source": "earth-rotation-angle",
      "target": "time-scales",
      "kind": "uses",
      "label": "UT1"
    },
    {
      "source": "tle-format",
      "target": "sgp4",
      "kind": "feeds",
      "label": "mean elements"
    },
    {
      "source": "sgp4",
      "target": "tle-format",
      "kind": "consumes",
      "label": "input"
    },
    {
      "source": "sgp4",
      "target": "keplerian-elements",
      "kind": "compares",
      "label": "osculating conversion"
    },
    {
      "source": "sgp4",
      "target": "perturbations",
      "kind": "models",
      "label": "J2 and drag"
    },
    {
      "source": "sgp4",
      "target": "reference-frames",
      "kind": "outputs",
      "label": "TEME"
    },
    {
      "source": "sgp4",
      "target": "time-scales",
      "kind": "uses",
      "label": "epoch"
    },
    {
      "source": "keplerian-elements",
      "target": "perturbations",
      "kind": "contrasts",
      "label": "no perturbations"
    },
    {
      "source": "ephemeris-interpolation",
      "target": "sgp4",
      "kind": "uses",
      "label": "samples"
    },
    {
      "source": "propagator-comparison",
      "target": "sgp4",
      "kind": "compares",
      "label": "accuracy and cost"
    },
    {
      "source": "propagator-comparison",
      "target": "method-hpop",
      "kind": "compares",
      "label": "accuracy and cost"
    },
    {
      "source": "propagator-comparison",
      "target": "method-numerical",
      "kind": "compares",
      "label": "accuracy and cost"
    },
    {
      "source": "propagator-comparison",
      "target": "method-two-body",
      "kind": "compares",
      "label": "accuracy and cost"
    },
    {
      "source": "propagator-comparison",
      "target": "ephemeris-interpolation",
      "kind": "recommends",
      "label": "many queries"
    },
    {
      "source": "method-two-body",
      "target": "keplerian-elements",
      "kind": "defines",
      "label": "solution"
    },
    {
      "source": "method-hpop",
      "target": "perturbations",
      "kind": "models",
      "label": "full force model"
    },
    {
      "source": "method-numerical",
      "target": "perturbations",
      "kind": "models",
      "label": "selected forces"
    },
    {
      "source": "crate-apsis-time",
      "target": "time-scales",
      "kind": "implements",
      "label": "Epoch"
    },
    {
      "source": "crate-apsis-coord",
      "target": "reference-frames",
      "kind": "implements",
      "label": "Eci, Ecef, Geodetic"
    },
    {
      "source": "crate-apsis-sgp4",
      "target": "sgp4",
      "kind": "implements",
      "label": "Satellite"
    },
    {
      "source": "standards-and-provenance",
      "target": "sgp4",
      "kind": "cites",
      "label": "Vallado 2006"
    },
    {
      "source": "standards-and-provenance",
      "target": "geodesy-wgs84",
      "kind": "cites",
      "label": "NIMA TR8350.2"
    },
    {
      "source": "standards-and-provenance",
      "target": "earth-rotation-angle",
      "kind": "cites",
      "label": "IERS 2010"
    },
    {
      "source": "overview",
      "target": "units-and-dimensions",
      "kind": "introduces",
      "label_en": "Introduces the reading order",
      "label_zh": "说明阅读顺序"
    },
    {
      "source": "overview",
      "target": "numerical-methods",
      "kind": "introduces",
      "label_en": "Introduces the reading order",
      "label_zh": "说明阅读顺序"
    },
    {
      "source": "units-and-dimensions",
      "target": "geodesy-wgs84",
      "kind": "applies-to",
      "label_en": "Gives the two measures a height uses",
      "label_zh": "给出高度的两种基准"
    },
    {
      "source": "numerical-methods",
      "target": "ephemeris-interpolation",
      "kind": "applies-to",
      "label_en": "Bounds the error of a table",
      "label_zh": "界定了表的误差"
    },
    {
      "source": "keplerian-elements",
      "target": "maneuvers",
      "kind": "enables",
      "label_en": "Is the orbit a manoeuvre changes",
      "label_zh": "是机动所改变的轨道"
    },
    {
      "source": "sgp4",
      "target": "maneuvers",
      "kind": "checks",
      "label_en": "Follows a manoeuvre",
      "label_zh": "跟随机动"
    },
    {
      "source": "perturbations",
      "target": "higher-order-gravity",
      "kind": "details",
      "label_en": "Details the oblateness term",
      "label_zh": "详述扁率项"
    },
    {
      "source": "perturbations",
      "target": "solar-radiation-pressure",
      "kind": "details",
      "label_en": "Details the third body term",
      "label_zh": "详述三体引力项"
    },
    {
      "source": "perturbations",
      "target": "atmospheric-drag",
      "kind": "details",
      "label_en": "Details the drag term",
      "label_zh": "详述阻力项"
    },
    {
      "source": "higher-order-gravity",
      "target": "geodesy-wgs84",
      "kind": "depends-on",
      "label_en": "Assumes the second order ellipsoid",
      "label_zh": "假定二阶椭球"
    },
    {
      "source": "solar-radiation-pressure",
      "target": "constellations",
      "kind": "sets-orbit",
      "label_en": "Fixes the plane of a sun-synchronous shell",
      "label_zh": "固定太阳同步壳层的轨道面"
    },
    {
      "source": "atmospheric-drag",
      "target": "operations-planning",
      "kind": "consumes-budget",
      "label_en": "Is the largest term in the fuel budget",
      "label_zh": "是燃料预算中最大的项"
    },
    {
      "source": "maneuvers",
      "target": "operations-planning",
      "kind": "consumes-budget",
      "label_en": "Is what the fuel budget pays for",
      "label_zh": "是燃料预算所支付的"
    },
    {
      "source": "constellations",
      "target": "access-and-availability",
      "kind": "determines",
      "label_en": "Determines the coverage figure",
      "label_zh": "决定覆盖数字"
    },
    {
      "source": "access-and-availability",
      "target": "handover-and-routing",
      "kind": "hands-over",
      "label_en": "Is what a handover moves between",
      "label_zh": "是切换所移动的"
    },
    {
      "source": "handover-and-routing",
      "target": "constellations",
      "kind": "depends-on",
      "label_en": "Follows the geometry of",
      "label_zh": "依赖于其几何"
    },
    {
      "source": "doppler-and-rate",
      "target": "tt-and-c",
      "kind": "measured-by",
      "label_en": "Is the measurement the chain depends on",
      "label_zh": "是链路依赖的测量"
    },
    {
      "source": "link-budget",
      "target": "tt-and-c",
      "kind": "enables",
      "label_en": "Decides whether a pass exists",
      "label_zh": "决定是否存在过境"
    },
    {
      "source": "atmospheric-propagation",
      "target": "link-budget",
      "kind": "degrades",
      "label_en": "Is the largest term in the budget",
      "label_zh": "是预算中最大的项"
    },
    {
      "source": "interference",
      "target": "link-budget",
      "kind": "consumes-margin",
      "label_en": "Consumes margin the budget left",
      "label_zh": "消耗预算留下的裕量"
    },
    {
      "source": "interference",
      "target": "doppler-and-rate",
      "kind": "corrupts",
      "label_en": "Corrupts rather than degrades",
      "label_zh": "腐化而非劣化测量"
    },
    {
      "source": "tt-and-c",
      "target": "operations-planning",
      "kind": "bounds-contact",
      "label_en": "Bounds the contact budget",
      "label_zh": "限定接触预算"
    },
    {
      "source": "operations-planning",
      "target": "scenario-simulation",
      "kind": "rehearsed-by",
      "label_en": "Is rehearsed by",
      "label_zh": "由其演练"
    },
    {
      "source": "maneuvers",
      "target": "scenario-simulation",
      "kind": "modelled-in",
      "label_en": "Is the model most simulations use",
      "label_zh": "是多数仿真使用的模型"
    },
    {
      "source": "link-budget",
      "target": "access-and-availability",
      "kind": "raises-mask",
      "label_en": "Sets the elevation mask",
      "label_zh": "决定仰角门限"
    },
    {
      "source": "solar-radiation-pressure",
      "target": "maneuvers",
      "kind": "budgets",
      "label_en": "Is a term in the propellant estimate",
      "label_zh": "是推进剂估算中的一项"
    }
  ],
  "title_zh": "概念图谱",
  "summary_zh": "ApsisRS 内核的概念及其相互关系。每个节点可打开解释该概念的文档。"
}