What is the effect of the stationary angular (cosine) effect on radar readings?

The stationary angular (cosine) effect impacts radar readings by causing a lower displayed target speed reading. This phenomenon occurs when the radar is not aligned directly with the target's line of motion; instead, it is at an angle. In such cases, the speed detected by the radar system is a function of the cosine of the angle between the radar beam and the target's direction of travel. Since this cosine value will be less than one (for angles other than zero degrees), the displayed speed reading will appear reduced.

For example, if the target is moving directly towards or away from the radar unit, the readings will closely represent the actual speed. However, as the angle increases, the effective speed decreases due to the cosine effect, resulting in an underestimation of the true speed of the target. This principle emphasizes the importance of positioning the radar correctly to ensure accurate speed measurements.