## 1 Introduction
### Prioritization Assessment of Capability Gaps  
There is little research in China that focuses on the priority assessment of capability gaps. Some research in this field exists abroad, but most of it is qualitative. The Technical Cooperation Program (TTCP) joint system and analysis team presents a qualitative analysis method that uses colors to identify the importance of capability gaps [36]. This is a completely subjective and sketchy approach. The US military \"Capabilities-Based Assessment Handbook 3.0\" introduced the sequencing of biometric information recognition-related capability gaps [37]. This method is based on a comparison of capability gaps among experts, regardless of uncertainty. [PERSON], from the research and development center at the US Army Corps of Engineers, examined the issue of capability gaps in the small-arms program for multi-service, using a multi-criteria decision analysis method [38]. The core of this method is an analytic hierarchy process, but its disadvantage is that there is no verification of the consistency of the judgment matrix. [PERSON] proposed a prioritization method for capability gaps, which was used to solve the problem of how to rank gaps in the combat capability of the Bulgarian armed forces [39]. This method takes into account three factors: the weight of the capability, the expected utility after filling the capability gap, and its urgency. It does not, however, consider the uncertainty. [PERSON] proposed a gap-ranking method based on the utility theory, which is used to solve the capability-gap ranking problem of brigade combat units [40]. This method is part of the United States-based Sandia National Laboratory Modernization assessment process. Most of the work needs to be completed by experts in relevant fields, and the method is subjective.  
[PERSON] rethinks the theoretical basis and systematic study of gap analysis, and expands on it while delineating its practicality and limitation. He came up with new ideas on these theoretical foundations by adopting the perspective of systems and value engineering [41]. By qualitatively analyzing the gap in the medium-lift capability of the United States Marine Corps, [PERSON] suggested that a medium-lift platform be added to fill the capability gap between light- and heavy-duty lift planes [42]. By analyzing the capabilities gap, [PERSON] of the United States Army argued that the quest for high-end capabilities left the Australian Defense Force vulnerable to mission failures, following which he finally obtained the prioritization of defense major capabilities [43]. By combining the soldier's expertise with a quantifiable analysis, [PERSON] proposed a gap-assessment method [44]. In this method, combatants on the mission determine the impact of measurable attributes from each capability gap; a mathematical approach is used to incorporate all of the combatants' responses into a single mission impact for each capability gap. In order to identify Air Force characteristics, the Office of Aerospace Studies of the United States Air Force conducts research on the methods and processes of capability-gap analysis through capability requirement statements, capability gap identification, capability gap statements, gap characterization, risk assessment, and gap prioritization [45]. In order for the Department of Homeland Security's capability to deal with biochemical threats, the U.S. Government Accountability Office submitted a report to the National Congress that elaborated the need for an analysis of the relevant capability gaps and put forward ways to identify and resolve related capability gaps [46]. These methods are qualitative and do not account for uncertainty.  
In this paper, in which we focused on the multiple uncertainties in the priority assessment of capability gaps, we adopted a method based on the conditional evidential network. Using the space-navigation-and-positioning system of systems as an example, we studied the priority assessment of capability gaps in weapon system of systems.