The Orbital height of GPS satellites from the earth's surface is approximately:

Question

Accepted Answer

The Orbital height of GPS satellites from the earth's surface is approximately:

**Option 3: 20,200 km**

**Explanation:**

*   **Why Option 3 (20,200 km) is correct:** GPS (Global Positioning System) satellites orbit the Earth at an altitude of approximately 20,200 kilometers (12,550 miles). This specific altitude is crucial for the GPS system to function effectively. At this height, the satellites have an orbital period of about 12 hours. This allows for a constellation of satellites to provide continuous global coverage, ensuring that a GPS receiver on Earth can "see" at least four satellites at any given time, which is necessary for accurate positioning. The semi-synchronous orbit (approximately 12-hour period) is a key characteristic of GPS satellites.

*   **Why Option 1 (36,000 km) is incorrect:** 36,000 km is the approximate altitude of geostationary satellites. Geostationary satellites orbit at a much higher altitude and remain in a fixed position relative to a point on Earth. This is suitable for communication satellites, but not for GPS, which requires satellites to move relative to the Earth's surface to provide accurate positioning data.

*   **Why Option 2 (970 km) is incorrect:** 970 km is a typical altitude for some low Earth orbit (LEO) satellites, such as those used for Earth observation or some communication constellations. This altitude is much lower than that of GPS satellites. Satellites at this altitude have a much shorter orbital period and would not provide the necessary global coverage and geometry for GPS functionality.

*   **Why Option 4 (30,200 km) is incorrect:** 30,200 km is not a standard or commonly used orbital altitude for any major satellite system. It falls between the GPS altitude and geostationary altitude, but it doesn't offer the advantages of either. GPS satellites require the specific altitude of approximately 20,200 km to achieve the desired orbital period and coverage.