How does primary radar detect objects?

Answer: B — By reflecting radio waves

Primary radar detects objects primarily by reflecting radio waves. This system operates by sending out a pulse of radio waves towards an object, such as an aircraft. When these radio waves encounter an object, they bounce back to the radar system. The radar then calculates the time it takes for the radio waves to return, which allows it to determine the distance to the object. This method is fundamental to the operation of primary radar because it relies solely on the emitted radio waves and their reflection off objects, making it independent of any onboard equipment or signals. By measuring the time delay between the transmitted pulse and the reception of the echo, the radar can accurately establish the position of the object in space. The other options describe different technologies or methods that are not used in primary radar detection. Satellite signals are used in satellite-based navigation and communication rather than primary radar systems. Primary radar does not utilize GPS for distance measurement, which is instead a characteristic of more advanced systems that provide additional data. Triangulation is associated with determining a position using multiple fixed points but is not a fundamental principle of how primary radar operates, which focuses on the direct reflection of waves.