Question

The multiple access method used in Global Positioning Systems is ________.

• A. FDMA
• B. CDMA
• C. WDMA
• D. TDMA

Hint:

CDMA is widely used in GPS due to its ability to separate signals using unique codes. Remember: \textbf{GPS = CDMA}. Always match communication systems with their optimal access technique.

Answer 1

The Correct Option is B

Step 1: Understanding GPS and Access Methods GPS (Global Positioning System) uses satellite signals to provide location and time information globally. To allow multiple satellites to transmit simultaneously without interference, an efficient multiple access technique is necessary.
Step 2: Role of CDMA in GPS
CDMA (Code Division Multiple Access) enables multiple transmitters to send data over a single communication channel using unique code sequences. It spreads each signal over a wide frequency band using a unique spreading code, allowing multiple users to share the same frequency range.
Step 3: Why not others?
FDMA: Divides bandwidth into frequency bands. Not used in GPS due to inefficiency for global time-synchronized data.
TDMA: Allocates time slots to users, not feasible for satellite positioning.
WDMA: Not relevant in satellite positioning systems.
Therefore, CDMA is ideal for GPS because it allows multiple satellites to broadcast on the same frequency band simultaneously without interference.