The discrete white noise acceleration model is often adopted to describe the target’s motion model, while
the state covariance is singularity, which results in the inactivation of the commonly used method for the calculation of
posterior Cram´er-rao lower bound(PCRLB). Besides, the observer position error may have great effect on the target tracking
performance. Therefore, firstly, the state vector is divided into a position part and a velocity part, which has nonsingularity
covariance respectively. Then, the common expression is got through constructing proper intermediate vectors and the
PCRLB in the presence of observer position error is derived. Finally, simulations and analysis are done with respect to the
multiple moving observers bearings-only passive tracking.