📍 Image Geolocation Error Calculator

Ground error from attitude knowledge, ephemeris & timing · off-nadir geometry · RSS

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Inputs

Results

Slant range to target
– km
Local elevation at target
– deg
Attitude contribution
– m
Ephemeris contribution
– m
Timing contribution
– m
Terrain contribution
– m
Total geolocation error
– m
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📖 How to use

  1. Bring the attitude knowledge RSS from the Pointing Budget tool; GPS-equipped LEO sats know position to ~5–10 m.姿态精度取指向预算工具的 RSS 值；带 GPS 的低轨卫星位置精度约 5–10 m。
  2. Geolocation degrades fast with the off-nadir angle — the slant range grows and the line of sight meets the ground at a shallower angle.定位精度随侧摆角迅速恶化——斜距变长且视线与地面夹角变小。
  3. Terrain height matters only off-nadir: an unknown Δh displaces the intersection by Δh·tan(incidence).地形高程仅在侧视时起作用：未知 Δh 使交点横移 Δh·tan(入射角)。
  4. Sub-10 m geolocation from LEO needs arcsec-class attitude knowledge — this tool shows exactly which term to buy down.低轨要做到 10 m 内定位需角秒级定姿——本工具能明确指出该在哪一项上投入。

Geolocation error model

With slant range ρ and local elevation ε at the target (spherical geometry as in the Coverage tool):

Attitude: e_att = ρ·δθ / sin ε — a knowledge error δθ sweeps the line of sight by ρ·δθ, stretched onto the ground by 1/sin ε.

Ephemeris: position error maps ≈ 1:1 to the ground. Timing: e_t = δt·v_ground with v_ground = √(μ/r)·R_E/r. Terrain: e_h = Δh·tan(90°−ε).

Independent terms RSS together. The model is a first-order estimate; rigorous work uses full sensor-frame projection with covariance.

All computation runs locally in your browser.

定位误差模型

设目标处斜距 ρ、当地高度角 ε（球面几何同覆盖工具）：

姿态: e_att = ρ·δθ / sin ε —— 定姿误差 δθ 使视线扫过 ρ·δθ，再按 1/sin ε 拉伸到地面。

星历: 位置误差近似 1:1 映射到地面。时间: e_t = δt·v_地面，v_地面 = √(μ/r)·R_E/r。地形: e_h = Δh·tan(90°−ε)。

各独立项 RSS 合成。此为一阶估计；严格计算需在传感器坐标系做完整投影与协方差分析。

全部计算在你的浏览器本地完成。