超宽带测距中，选目的节点和参考节点。输入节点数量为N和希望的参考节点数量为K，函数返回一个表示目的的节点的整数Nx和一个K维的包括了参考节点ID号的矢量Ref。-Ultra-Wideband Ranging choose destination node and reference nodes. The number of input nodes for N and hope the number of reference node K, the purpose of function that returns a whole number of nodes Nx and including a K-dimensional reference vector of node ID No. Ref.