Patent ID: 11959799
Assignee: ASELSAN ELEKTRONIK SANAYI VE TICARET ANONIM SIRKETI
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 1:
2. The phase sensitive optical time domain reflectometry based distributed acoustic sensing system according to the claim 1, wherein an optical pulse, p(t), injected into a fiber optic cable is represented as follows:, p
          ⁡
          
            (
            t
            )
          
        
        ⁢
        
        =
      
    
    
      
        
        ⁢
        
          
            ∑
            
              k
              =
              
                -
                ∞
              
            
            ∞
          
          ⁢
          
            
          
          ⁢
          
            [
            
              
                
                  f
                  ⁡
                  
                    (
                    t
                    )
                  
                
                ⁢
                
                  Π
                  ⁡
                  
                    (
                    
                      
                        t
                        -
                        
                          kT
                          p
                        
                      
                      
                        T
                        w
                      
                    
                    )
                  
                
              
              +
              
                
                  ϵ
                  1
                
                ⁢
                
                  f
                  ⁡
                  
                    (
                    t
                    )
                  
                
                ⁢
                
                  (
                  
                    1
                    -
                    
                      Π
                      ⁡
                      
                        (
                        
                          
                            t
                            -
                            
                              kT
                              p
                            
                          
                          
                            T
                            w
                          
                        
                        )
                      
                    
                  
                  )
                
              
              +
              
                
                  ϵ
                  2
                
                ⁢
                
                  g
                  ⁡
                  
                    (
                    t
                    )
                  
                
              
            
            ]
          
        
      
    
  
  
    
      
        
        =
      
    
    
      
        
        ⁢
        
          
            
              ∑
              
                k
                =
                
                  -
                  ∞
                
              
              ∞
            
            ⁢
            
              
            
            ⁢
            
              [
              
                
                  
                    (
                    
                      1
                      -
                      
                        ϵ
                        1
                      
                    
                    )
                  
                  ⁢
                  
                    f
                    ⁡
                    
                      (
                      t
                      )
                    
                  
                  ⁢
                  
                    Π
                    ⁡
                    
                      (
                      
                        
                          t
                          -
                          
                            kT
                            p
                          
                        
                        
                          T
                          w
                        
                      
                      )
                    
                  
                
                +
                
                  
                    ϵ
                    1
                  
                  ⁡
                  
                    (
                    
                      
                        f
                        ⁡
                        
                          (
                          t
                          )
                        
                      
                      +
                      
                        g
                        ⁡
                        
                          (
                          t
                          )
                        
                      
                    
                    )
                  
                
                +
                
                  
                    (
                    
                      
                        ϵ
                        2
                      
                      -
                      
                        ϵ
                        1
                      
                    
                    )
                  
                  ⁢
                  
                    g
                    ⁡
                    
                      (
                      t
                      )
                    
                  
                
              
              ]
            
          
          ,
        
      
    
  

wherein f(t) and g(t) are CW optical signals generated from the coherent laser source and the incoherent laser source, respectively; ϵ1 and ϵ2 are extinction ratio values of optical paths along the fiber optic cable, respectively; TP is a pulse repetition period and Π(.) represents a rectangular pulse, wherein the rectangular pulse is defined as:, Π
    ⁡
    
      (
      
        t
        
          T
          w
        
      
      )
    
  
  =
  
    {
    
      
        
          
            1
            ,
          
        
        
          
            0
            ≤
            t
            ≤
            
              T
              w
            
          
        
      
      
        
          
            0
            ,
          
        
        
          
            otherwise
            .