Patent ID: 11914100
Assignee: SOUTHEAST UNIVERSITY
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method for determining an inverse of gravity correlation time, comprising:
obtaining an observation value using a global navigation satellite system (GNSS);
measuring a gravity of moving bases using a gravity sensor;
for a gravity anomaly of an mthorder Gauss Markov model, according to a gravity sensor root mean square error σf, a GNSS height root mean square error σh, an a priori gravity root mean square σg, and a gravity filter cutoff frequency ωc during said gravity measurement of moving bases, performing iterative calculation by using Formula (1), to obtain an inverse of gravity correlation time β, the gravity filter comprising an impulse response low-pass filter,, β
      =
      
       
        [
        
         
          
           (
           
            1
            +
            
             
              β
              2
             
             /
             
              ω
              c
              2
             
            
           
           )
          
          m
         
         ⁢
         
          
           
            ω
            c
            
             2
             ⁢
             m
            
           
           
            C
            m
           
          
          [
          
           
            
             σ
             f
             2
            
            
             σ
             g
             2
            
           
           +
           
            
             ω
             c
             4
            
            ⁢
            
             
              σ
              h
              2
             
             
              σ
              g
              2
             
            
           
          
          ]
         
        
        ]
       
       
        1
        
         
          2
          ⁢
          m
         
         -
         1
        
       
      
     
     ,
     

     
      
       
        where
        ⁢
           
        
         C
         m
        
       
       =
       
        
         2
         ⁢
         
          
           (
           
            
             2
             ⁢
             m
            
            -
            2
           
           )
          
          !!
         
        
        
         
          (
          
           
            2
            ⁢
            m
           
           -
           3
          
          )
         
         !!
        
       
      
      ;
     
    
   
   
    
     (
     1
     )
    
   
  
 

(2) assuming that β<<ωc, and simplifying Formula (1) as:, β
      ≈
      
       
        [
        
         
          
           ω
           c
           
            2
            ⁢
            m
           
          
          
           C
           m
          
         
         [
         
          
           
            σ
            f
            2
           
           
            σ
            g
            2
           
          
          +
          
           
            ω
            c
            4
           
           ⁢
           
            
             σ
             h
             2
            
            
             σ
             g
             2
            
           
          
         
         ]
        
        ]
       
       
        1
        
         
          2
          ⁢
          m
         
         -
         1
        
       
      
     
     ,
    
   
   
    
     (
     2
     )
    
   
  
 

where Formula (2) is an explicit expression, and the inverse of gravity correlation time β on the left can be obtained by calculating known quantities on the right,
wherein a relationship is established between the inverse of gravity correlation time and a filter cutoff frequency and according to changes in the filter cutoff frequency, a forward and backward Kalman filter during data processing on a gravity measurement of a moving base is adjusted.