Patent ID: 11953325
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 1:
2. The direction calculation apparatus according to claim 1, wherein
the first instructed force sensation vector is defined as fdc=|fdc|[cos θd, sin θd]T (where θd represents an angle formed by a vector [1, 0]T and the first instructed force sensation vector), and
the calculating the second instructed force sensation vector further comprises:
calculating, from the first matrix rc and the second matrix rs, an azimuth angle θb indicating an azimuth of the force sensation presentation device, the azimuth taking into account an influence of geomagnetic distortion in the reference coordinate system at the current position by Math. 8:, [
     
      Math
      .
         
      8
     
     ]
    
   
   
    
   
  
  
   
    
     
      
       θ
       b
      
      =
      
       atan
       ⁢
       2
       ⁢
       
        (
        
         
          mc
          y
         
         ,
         
          mc
          x
         
        
        )
       
      
     
     ⁢
     

     
      
       
        [
        
         
          
           
            mc
            x
           
          
         
         
          
           
            mc
            y
           
          
         
         
          
           
            mc
            z
           
          
         
        
        ]
       
       =
       
        
         
          
           r
           c
          
          (
          
           r
           s
          
          )
         
         
          -
          1
         
        
        [
        
         
          
           1
          
         
         
          
           0
          
         
         
          
           0
          
         
        
        ]
       
      
      ;
     
    
   
   
     
   
  
 

 and
calculating the second instructed force sensation vector fdb by Math. 9:

fdb=|fdc|[cos(θd−θb), sin(θd−θb)]T.  [Math. 9]