A New Precision Evaluation Method for Signals of opportunity Based on CRAMER-RAO Lower Bound in Finite Error

The unknown precision o f the Signal o f Opportunity(SoOs) is a critical problem hindering it being applied to navigation. Using high precision signals will improve the performance o f the navigation system but using low precision signals will pollute the results. This paper presents a method to identify the accuracy level o f each Basic Station(BS) signals to pick an optimal SoOs combination with least location error. All o f the referring location, Basic Station location, the receiver location, and the error power o f the SoOs will be the factors affecting the accuracy level. The CRLB is applied in this paper to build the accuracy level model. In the condition that the receiver referring location with finite error(within 3km) which the confidence is 0.95(26), the probability that the accuracy level estimation is precise is higher than 80% in the simulation experiments. This method provides a new way to value the SoOs accuracy by a simple example. Only the principle o f this method is introduced in this paper, and some adjustments should be made in the actual works.