# A Heterogeneous Battlefield Situation Information Sharing Method Based on Content
## Sharing Framework of Heterogeneous Battlefield Situation Information
### Content Consistency Analysis of Heterogeneous Battlefield Situation Information  
To meet the need for joint operations, the research, development, and assembly of combat systems in the military field are increasingly focused on universality and integration. However, the upgrading of information systems cannot be done overnight. To maintain the continuity of combat effectiveness of the army and the smoothness of equipment evolution, the coexistence of multiple information systems usually is the case for current armies. Take the current U.S. military forces as an example: there are various information systems used by their equipment, such as SADL(Situation Awareness Data Link), Link 16, VMF (Variable Message Format), and Link 22. \begin{table}
\begin{tabular}{l l} \hline \hline
**Notation** & **Definition** \\ \hline \(e\) & Entity. This represents an independently identifiable, tangible geographical target, combat unit, or intangible concept. \\ \(a\) & Attribute variable. This represents an attribute of \(e\) \\ \(r\) & Relationship variable. This represents a kind of relationship among entities. \\ \(s\) & State variable. This represents an observable state of \(e\), e.g., the state of motion or operation of an equipment. It is closely related to the internal attribute information of \(e\). \\ \(E\) & Non-empty finite set of entities \\ \(A\) & Attribute set. This represents a collection of attribute variables. \\ \(R\) & Relationship set. This represents a collection of relationship variables. \\ \(S\) & State set. This represents a collection of state variables. \\ \(EC\) & Entity class. This is an abstraction of entities that possess the same features. \\ \(A^{\prime}_{c}\) & Feature attribute set. This represents the unique set of attributes possessed by \(EC\), which is denoted as \(EC\leftrightarrow A^{\prime}_{c}\); while the corresponding state set related to \(A^{\prime}_{c}\) is denoted as \(S^{\prime}_{c}\). \\ \(A_{c}\) & Attribute set of \(EC\), which is denoted as \(A_{c}\)\(\mapsto EC\); while the corresponding state set related to \(A_{c}\) is denoted as \(S_{c}\). \\ \(A_{cc}\) & The “common-attribute set” of \(EC\). This is a subset of \(A_{c}\) and represents the set of attributes that each entity belonging to \(EC\) should possess, which is denoted as \(EC\)\(\rightarrow\)\(A_{cc}\); while the corresponding state set related to \(A_{cc}\) is denoted as \(S_{cc}\). \\ \(A_{co}\) & The “occaional-attribute set” of \(EC\). This is a subset of \(A_{c}\) and represents the set of attributes that not all entities belonging to \(EC\) should possess; while the corresponding state set related to \(A_{co}\) is denoted as \(S_{co}\). \\ \(i\),\(j\),\(k\),\(l\),\(g\) & The mark number of specific \(e\), \(a\), \(s\), \(EC\), \(A_{c}\), or \(S_{c}\), etc. \\ \(n\) & The number of \(e\), \(a\), \(s\), \(EC\), \(A_{c}\), or \(S_{c}\), etc. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: A list of major notations. As shown in Figure 1, when conducting joint operations, multiple combat units such as fighters, tanks, ships, satellites, or radar equipped with different information systems may exist in the same combat area at the same time; where any combat unit with communication capabilities can be a provider of battlefield situation information, as well as a user of battlefield situation information. In the process of operation, combat units are the basic units involved in combat tasks, and a combat mission can usually be accomplished through the cooperative action of multiple basic combat units. The battlefield situation information describes the observable states of these combat units in the battlefield space at a moment, including where they are, what they are doing, what status of movement they are in, what kind of relationships among them exist, and so on. Although information in different systems is heterogeneous, it is consistent from the aspect of content expressed in the information.