Question

Identify the CORRECT statement(s).

• A. For accurate GPS positioning, Geometric Dilution of Precision should be as large as possible.
• B. Integer ambiguity is associated with carrier frequency observation of GPS signal.
• C. GPS is one way ranging system for user.
• D. GPS is two way ranging system for user.

Hint:

For accurate GPS positioning, ensure that the GDOP is as small as possible. Also, integer ambiguity is crucial in carrier frequency observation, especially in high-precision GPS systems.

Answer 1

The Correct Option is B, C

- Option (A): For accurate GPS positioning, the Geometric Dilution of Precision (GDOP) should be as small as possible, not large. The GDOP is a measure of the geometry of the satellite constellation and affects the precision of the positioning. A smaller GDOP value means better accuracy in positioning, so this statement is incorrect.
- Option (B): Integer ambiguity refers to the problem of determining the correct integer number of carrier cycles in the GPS signal, which is crucial in high-precision GPS applications. This ambiguity is associated with carrier frequency observations, where the receiver must determine the correct number of complete cycles of the carrier wave to improve accuracy. Therefore, this statement is correct.
- Option (C): GPS is a one-way ranging system for the user. The satellites transmit signals, and the receiver calculates its position based on the travel time of these signals. There is no need for a return signal from the receiver, which makes it a one-way ranging system. This statement is correct.
- Option (D): GPS is not a two-way ranging system for the user. The receiver only receives signals from the satellites and does not send any ranging signal back to the satellites. Therefore, this statement is incorrect.
Thus, the correct answers are (B) and (C).