  Mission planners for aircraft operating under threat of detection from
ground-based radar systems are often concerned with the probability of
detection. Current approaches to path planning in such environments consider
the radar state (i.e. radar position and parameters) to be deterministic and
known. In practice, there is uncertainty in the radar state which induces
uncertainty in the probability of detection. This paper presents a method to
incorporate the uncertainty of the radar state in a single-pulse radar
detection model. The method linearizes the radar detection model with respect
to the the radar state and uses the linearized models to estimate, to the first
order, the variance of the probability of detection. The results in this paper
validate the linearization using Monte Carlo analysis and illustrate the
sensitivity of the probability of detection to radar state uncertainty.
