Attitude Sensors
| Sensor敏感器 | Accuracy (3σ)精度（3σ） | Notes备注 |
|---|
| Star tracker星敏感器 | 1–10″ (XY), 10–30″ (roll) | Blinded near sun/moon; 1–10 Hz日月致盲；1–10 Hz |
| Fine sun sensor精太阳敏感器 | 0.05–0.5° | Daylight only仅光照区 |
| Coarse sun sensor粗太阳敏感器 | 1–5° | Safe mode staple安全模式常用 |
| Magnetometer磁强计 | 0.5–3° (attitude)（定姿） | Field model limited; LEO only受磁场模型限制；仅低轨 |
| Earth horizon sensor红外地平仪 | 0.05–0.25° | Pitch/roll only仅俯仰/滚动 |
| GNSS | 5–10 m (pos) | Position/time for LEO低轨位置/时间 |
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Gyros (rate sensors)
| Class档次 | ARW | Bias stability零偏稳定性 | Typical use典型应用 |
|---|
| MEMS | 0.1–1 °/√h | 1–10 °/h | CubeSats, coarse rate立方星、粗测速 |
| Tactical FOG战术级光纤陀螺 | 0.01–0.1 °/√h | 0.1–1 °/h | Smallsats小卫星 |
| Navigation FOG/RLG导航级光纤/激光陀螺 | ≤ 0.005 °/√h | ≤ 0.01 °/h | High-accuracy EO, GEO高精度遥感、GEO |
| Hemispherical resonator半球谐振陀螺 | ≤ 0.001 °/√h | ≤ 0.005 °/h | Premium, long life高端长寿命 |
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Actuators
| Actuator执行机构 | Capability能力 | Notes备注 |
|---|
| Reaction wheels (CubeSat)反作用轮（立方星） | 0.001–0.05 N·m·s, ~1 mN·m | 3+1 skewed sets3+1 斜装 |
| Reaction wheels (smallsat)反作用轮（小卫星） | 0.4–12 N·m·s, 0.02–0.2 N·m | EO workhorse遥感主力 |
| Reaction wheels (large)反作用轮（大型） | 25–70 N·m·s, 0.2–0.4 N·m | GEO |
| CMG | 10–5000 N·m·s, 10–300 N·m | Agile imaging, stations敏捷成像、空间站 |
| Magnetorquers磁力矩器 | 0.2–500 A·m² | LEO dumping/detumble低轨卸载/消旋 |
| RCS thrusters姿控推力器 | 0.1–20 N | Fast dumps, safe mode, GEO快速卸载、安全模式、GEO |
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Geomagnetic Field vs Altitude
| Altitude高度 | Equatorial B赤道 B | Polar B极区 B |
|---|
| 350 km | 26.2 µT | 52.5 µT |
| 500 km | 24.5 µT | 48.9 µT |
| 800 km | 21.5 µT | 43.1 µT |
| 1000 km | 19.8 µT | 39.6 µT |
| GEO | 0.106 µT | – |
Dipole model B_eq = M/r³, M = 7.96×10¹⁵ T·m³. Magnetic control is essentially a LEO technique — at GEO the field is 200× weaker.偶极子模型 B_eq = M/r³，M = 7.96×10¹⁵ T·m³。磁控本质上是低轨手段——GEO 磁场弱 200 倍。
📖 How to use
- Use these as early-design placeholders in the sizing tools; replace with vendor datasheets as the design matures.方案阶段可将本页数值填入各选型工具；设计深入后以厂商手册替换。
- Rules of thumb: wheel torque authority ≥ 10× worst disturbance; magnetorquer dump torque ≥ 2× secular disturbance; sensor accuracy ≈ ⅓ of the pointing requirement.经验法则：轮子力矩 ≥ 10× 最恶劣干扰；磁卸载力矩 ≥ 2× 长期干扰；敏感器精度 ≈ 指向指标的 ⅓。