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Mission geometry

GEO Look Angle Calculator

Point an earth-station antenna using azimuth, elevation and slant range.

Given / choose the units

Diagrams update as you edit. Run Calculate to refresh numerical results.

Enter the design inputs, then calculate to inspect the results.

Swipe the diagram sideways to see the full view. With a keyboard, focus the diagram and use the arrow keys.

Local horizon and compass bearingElevation 54.51°Local horizonNESWAzimuth 190.37°Slant range: 36813.9 km · Above horizon
Side view uses the actual elevation angle; the compass shows clockwise bearing from north. Below-horizon geometry is shown below the dashed line and is not a visible direct link.

Understand the system

Pointing vocabulary

The subsatellite point is the surface intersection of the Earth-center-to-satellite line. Azimuth specifies a compass direction around the local horizon; elevation is the angle above that horizon. Together these are the look angles.

Source: finalExam.pdf · PDF page 3

Common mistakes

  • Longitude difference needs the correct sign and wrap.
  • GEO altitude is not every station’s slant range.
  • A numeric azimuth does not establish visibility below the horizon.

Continue the signal path

Orbit & Kepler Calculator →RF Path, PFD and Received Power Calculator · use this result →Doppler and Propagation Delay Tool →

Design guide

Use the result with engineering context

Technical content reviewed

When this tool is useful

  • Calculating subsatellite point with engineering models
  • Calculating azimuth and elevation with engineering models
  • Calculating slant range with engineering models

What the result includes

  • Point an earth-station antenna using azimuth, elevation and slant range.
  • Explanations, assumptions and links to related satellite calculators

What the model does not guarantee

  • Analytical engineering models do not replace measurements or a mission-specific design review.
  • Spectrum permissions, launch operations and real satellite tracking are outside these calculators.

Worked approach

Subsatellite point

Form the vector from the station to the spacecraft and resolve it into local east, north and up components. Slant range is its length. atan2 uses both signs and preserves the azimuth quadrant; normalize the azimuth to 0–360°. Elevation at or below zero is not a usable unobstructed above-horizon path.

Common decisions

Questions engineers ask

Which topics does GEO Look Angle Calculator cover?

Subsatellite point; Azimuth and elevation; Slant range; Visibility.

How should I check my work in GEO Look Angle Calculator?

Read the stated assumptions and source references, check units and independently repeat a worked example before relying on the result.

Does GEO Look Angle Calculator operate real satellite equipment?

No. This is a browser-based educational resource. It does not transmit RF signals, command spacecraft or certify a working link.

Related build evidence

Related embedded-system engineering

Aqua Sync is a separate connected-device project, not evidence of a satellite deployment.

See the project

Apply it to real hardware

Discuss an engineering prototype

Share the required behavior, interfaces and how you plan to test the result.

Discuss the system