# A Heterogeneous Battlefield Situation Information Sharing Method Based on Content
## 4 Construction of the Unified Battlefield Situation Information Space
### Aggregation of Internal Description Information about Entities  
Description information about entities is usually carried by the messages delivered within systems, and then, the process of information aggregation can be viewed as the process of aggregating message content. Suppose \(m_{i}\) is a piece of message that describes the information of \(e_{i}\) belonging to \(EC_{i}\). Use \(TM\) (\(m_{i}\)) to denote the tree parsed from \(Doc(m_{i})\) that is generated after decoding and structured operation of message \(m_{i}\) and \(T(e_{i})\) to denote the parse tree of \(Doc(e_{i})\) that stores the description information of \(e_{i}\). As can be seen from Definition 3, when \(e_{i}\) is completely described, the tree structure formed by all the concepts involved should be a sub-tree of \(T_{LEC_{i}}\), then we can get the following Equation (3), where \(S^{\prime\prime}_{e_{i+n}}=S^{\prime}_{e_{i+n}}\cup S^{\prime}_{e_{i+n}o}\wedge A ^{\prime\prime}_{e_{i+n}}=A^{\prime}_{e_{i+n}}\cup A^{\prime}_{e_{i+n}o}\):  
\[T(e_{i})=(EC_{i}(EC_{i+1}(...(EC_{i+n}(S^{\prime\prime}_{e_{i+n}},A^{\prime \prime}_{e_{i+n}})S^{\prime\prime}_{e_{i+n-1}},A^{\prime\prime}_{e_{i+n-1}})... ),S^{\prime\prime}_{e_{i}},A^{\prime\prime}_{e_{i}}))(n\in\mathbf{N}). \tag{3}\]  
Let the collection of messages describing \(e_{i}\) from \(\mathbf{A}\) and \(\mathbf{B}\) be \(M_{i}=\{m_{1}\), \(m_{2}\),..., \(m_{q}\,|\,q\in\mathbf{N}\}\), then the tree structure obtained after information aggregation should be the same as \(T(e_{i})\). Denote the initial information tree structure describing \(e_{i}\) in the description document of \(e_{i}\) in UISas \(T^{\prime}_{0}(e_{i})\). Assume that no message describing \(e_{i}\) has been received at present and any subsequent message describing \(e_{i}\) is correct, i.e., it satisfies the constrains of logic and semantics between attributes and states that describe a specific entity. When the first message \(m_{1}\) describing \(e_{i}\) arrives, \(T_{M}(m_{i})\) is then the initial information tree structure of \(e_{i}\), which is denoted as \(T^{\prime}_{1}(e_{i})\). Then, we can get Equation (4):  
\[T^{\prime}_{1}(e_{i})=T_{M}(m_{1})=(EC_{i}(EC_{i+1}(...(EC_{i+k_{1}}(P^{\prime }_{1}S^{\prime\prime}_{e_{i+k_{1}}},P^{\prime}_{1}A^{\prime\prime}_{e_{i+k_{1}}}),P^{\prime}_{1}S^{\prime\prime}_{e_{i+k_{1}-1}},P^{\prime}_{1}A^{\prime\prime} _{e_{i+k_{1}-1}})...),P^{\prime}_{1}S^{\prime\prime}_{e_{i}},P^{\prime}_{1}A^{ \prime\prime}_{e_{i}})) \tag{4}\]where \(k_{1}\leq n\wedge\{P_{1}^{\prime}S_{c_{j}}^{\prime\prime}\subseteq S_{c_{j}}^{ \prime\prime},\,P_{1}^{\prime}A_{c_{j}}^{\prime\prime}\subseteq A_{c_{j}}^{ \prime\prime}|j\in[i,\,i+n]\}\). When the second message \(m_{2}\) arrives, Equation (5) holds:  
\[T_{M}(m_{2})=(EC_{i}(EC_{i+1}(...(EC_{i+k_{2}}(P_{2}S_{c_{i+k_{2}}}^{\prime \prime},P_{2}A_{c_{i+k_{2}}}^{\prime\prime}),P_{2}S_{c_{i+k_{2}-1}}^{\prime \prime},P_{2}A_{c_{i+k_{2}-1}}^{\prime\prime})...),P_{2}S_{c_{i}}^{\prime \prime},P_{2}A_{c_{i}}^{\prime\prime})) \tag{5}\]  
where \(k_{2}\leq n\wedge\{P_{2}S_{c_{j}}^{\prime\prime}\subseteq S_{c_{j}}^{\prime \prime},\,P_{2}A_{c_{j}}^{\prime\prime}\subseteq A_{c_{j}}^{\prime\prime}|j\in[ i,\,i+n]\}\).