What is the mask angle in GPS, and what does it signify?

What is the mask angle in GPS, and what does it signify?

• A. The mask angle is a vertical angle of 0° from the horizon.
• B. The mask angle is a vertical angle of 10 to 20 degrees from the horizon, below which signals from GPS satellites are less reliable.
• C. The mask angle refers to a horizontal angle.
• D. The mask angle is unrelated to signal reliability.

Answer: (B)

The mask angle is an elevation threshold used to decide which GPS satellites are considered usable. It’s a vertical angle measured from the horizon up to the satellite. Satellites with elevation angles below this threshold are typically ignored because their signals are weaker and more affected by atmospheric conditions, multipath, and poor geometry, which reduces positioning reliability. A common range for this threshold is about 10 to 20 degrees above the horizon, meaning satellites higher than that angle are used and those lower are treated as less reliable. It’s not a horizontal angle, and it directly relates to signal quality, not unrelated to reliability.

The mask angle is an elevation threshold used to decide which GPS satellites are considered usable. It’s a vertical angle measured from the horizon up to the satellite. Satellites with elevation angles below this threshold are typically ignored because their signals are weaker and more affected by atmospheric conditions, multipath, and poor geometry, which reduces positioning reliability. A common range for this threshold is about 10 to 20 degrees above the horizon, meaning satellites higher than that angle are used and those lower are treated as less reliable. It’s not a horizontal angle, and it directly relates to signal quality, not unrelated to reliability.