Algorithm 1. Calculation method for fuzzy entropy of radar signal sequences.
Define: Signal sequence $X\left(n\right),n\in [1,N]$; sequence length N; generated sub-sequence length m; exponential factor p; similarity threshold q
Input: Signal sequence $X$(n)
Output: Fuzzy entropy of $X$(n)
1	$X_n^m\left(i\right)=\left\{\left[x\right(i),x(i+1),\dots ,x(i+m-1\left)\right]\right\},i\in [1,n-m+1]$ z Generate sub-sequence sets $X_n^m\left(i\right)$
2	$x_0(i)={\displaystyle \frac{1}{m}}{\sum }_{k=0}^{m-1}x(i+k),i\in [1,n-m+1]$ // Obtain the mean of each sub-sequence $x_0\left(i\right)$
3	$X_n^m\left(i\right)=X_n^m\left(i\right)-x_0\left(i\right), i\in [1,n-m+1]$
4	$d_{ij}^m={\mathrm{m}\mathrm{a}\mathrm{x}}_k\left|X_n^m(i+k)-X_n^m(j+k)\right|,i,j\in [1,n-m+1],i\ne j,k\in [0,m-1]$ // Obtain the maximum distance $d_{ij}^m$ between two sub-sequences in $X_n^m\left(i\right)$
5	$D_{ij}^m=\mu \left(d_{ij}^m,p,q\right)=\mathrm{e}\mathrm{x}\mathrm{p}\left({\displaystyle \frac{-{\left(d_{ij}^m\right)}^p}{q}}\right)$ // Calculate fuzzy membership degree $D_{ij}^m$
6	${\varphi }^m(p,q)={\displaystyle \frac{1}{N-m}}{\sum }_{i=1}^{N-m}\left({\displaystyle \frac{1}{N-m-1}}{\sum }_{j=1,j\ne i}^{N-m}{D}_{ij}^m\right)$
7	m = m + 1, repeat step 5 to obtain ${\varphi }^{m+1}(p,q)$
8	${\mathrm{E}\mathrm{n}}_F(m,p,q)=\mathrm{l}\mathrm{n}\left[{\varphi }^m(p,q)\right]-\mathrm{l}\mathrm{n}\left[{\varphi }^{m+1}(p,q)\right]$
9	Return ${\mathrm{E}\mathrm{n}}_F(m,p,q)$ as the fuzzy entropy of $X\left(n\right)$