Which of the following best describes a characteristic of fixed surveillance?

The characteristic of fixed surveillance is best described as continuous observation from a single position. This type of surveillance involves monitoring a specific location or individual consistently without changing vantage points. The aim is to gather comprehensive information over a prolonged period, which is vital for assessing movements, behaviors, and actions in detail.

In contrast, intermittent observation from multiple locations suggests a more dynamic approach, which does not align with the concept of "fixed" surveillance. Using technology like drones introduces variability in focus and mobility, which falls outside the fixed observation definition. Quick access to backup units may pertain to operational tactics but does not define the nature of fixed surveillance itself. Overall, the essence of fixed surveillance lies in its stability and constant monitoring from a designated spot.