🛰️ Satellite Pass Predictor (TLE)

Upcoming visible passes from a TLE & your ground station — AOS, LOS, max elevation, duration

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Orbit — TLE / Elements

Paste the two TLE lines (get them from CelesTrak).粘贴两行 TLE(可从 CelesTrak 获取)。

Example above is the ISS — replace with a current TLE for accurate results.

Ground Station

Upcoming Passes

Loading orbit library…
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📖 How to use

  1. Paste a current TLE (both lines) from CelesTrak — the fresher, the more accurate — or switch to Orbital elements and type the six Keplerian elements directly.从 CelesTrak 粘贴最新的两行根数 TLE(两行都要)——越新越准;也可切换到六根数直接填写开普勒根数。
  2. The two forms stay in sync: pasting a TLE fills the six elements; editing any element regenerates the TLE (drag terms are kept from the last pasted TLE).两种输入相互同步:粘贴 TLE 会填入六根数,修改任一根数会重新生成 TLE(大气阻力项沿用上次粘贴的 TLE)。
  3. Enter your ground-station latitude, longitude and altitude, or click 📍 Detect to use your location.输入地面站纬度、经度、海拔,或点 📍 Detect 使用当前位置。
  4. Set the minimum elevation (horizon mask) and how many hours ahead to search.设置最低仰角(地平遮挡)和向后预测的小时数。
  5. Click Predict passes to list upcoming passes with AOS, LOS, maximum elevation and duration.点 Predict passes 列出未来过境的 AOS、LOS、最大仰角和时长。
  6. Times are shown in your browser's local timezone; everything runs on your device.时间按浏览器本地时区显示;全部在本地运算,坐标不上传。

How satellite pass prediction works

A TLE (Two-Line Element set) encodes a satellite's orbit at a reference epoch. This tool runs the standard SGP4 propagator (via the open-source satellite.js library) to compute the satellite's position over time, then converts it to look angles (azimuth/elevation) from your ground station. Whenever elevation rises above your horizon mask, a pass begins (AOS — Acquisition of Signal) and ends when it drops below again (LOS — Loss of Signal).

For accurate predictions, always use a fresh TLE (less than a few days old) — orbital elements decay quickly, especially for low CubeSats. Times are shown in your browser's local timezone. Everything runs locally; your coordinates never leave your device.

卫星过顶预测原理

TLE(两行根数)以一个参考历元编码卫星轨道。本工具运行标准的 SGP4 传播器(通过开源库 satellite.js)计算卫星随时间的位置,再换算为相对地面站的视角(方位/仰角)。每当仰角升过你的地平遮挡时,一次过境开始(AOS —— 信号捕获),再次落到其下时结束(LOS —— 信号丢失)。

要预测准确,请始终使用最新的 TLE(不超过几天)——轨道根数衰减很快,低轨立方星尤甚。时间按你浏览器的本地时区显示。一切在本地运行,你的坐标绝不离开你的设备。