GEO station-keeping requirement: Typical on-station pointing accuracy for a commercial geostationary satellite must be maintained within approximately how many degrees?
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A0.1°
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B1.0°
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C2.0°
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D0.5°
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E5.0°
Answer
Correct Answer: 0.1°
Explanation
Introduction / Context:Geostationary satellites are assigned small orbital slots. To avoid interference with neighbors and maintain ground link quality, satellites must be kept within tight longitude/latitude bounds, expressed as an angular “box.”
Given Data / Assumptions:
- Commercial GEO satellite with routine station-keeping.
- Regulatory and coordination constraints define an on-station accuracy requirement.
Concept / Approach:
Typical station-keeping limits are on the order of ±0.05° to ±0.1° in longitude and latitude (combined box about 0.1–0.2°). This ensures pointing overlap with Earth-station beams and protects adjacent satellites from interference.
Step-by-Step Solution:
Recognize standard GEO “box” sizes from fleet ops (e.g., ±0.05–0.1°).Pick the nearest option that represents common contractual limits.Hence 0.1° is the most representative choice in the options provided.Verification / Alternative check:
Operator handbooks and ITU coordination documents align with ~0.1° class control for commercial communications payloads.
Why Other Options Are Wrong:
- 0.5–2°: far too loose; would risk interference and ground beam mispoint.
- 1–2° are characteristic of very coarse pointing, not acceptable for GEO comms slots.
Common Pitfalls:
- Confusing steerable antenna pointing accuracy with orbital station-keeping accuracy.
Final Answer:
0.1°