Patent ID: 11908319
Assignee: XIDIAN UNIVERSITY
Field: Control (Instruments)
Classification: CPC G | IPC G

Claim 5:
6. The speed measurement method according to claim 1, wherein, in step 7), setting a measurement threshold δ and merging the temporal data based on the measurement threshold δ is achieved by the step of:
7a) if the measurement threshold δ has been obtained then step 7b) is performed;
if the measurement threshold δ has not been obtained, the geomagnetic sensor is placed beside the road to record an output waveform generated by the geomagnetic sensor when the vehicle passes the geomagnetic sensor in the case of a vehicle being detected as multiple vehicles; difference data of adjacent detection times is obtained by waveform analysis; an operation is repeated several times; and
a Gaussian distribution model, f
   ⁡
   (
   x
   )
  
  =
  
   
    1
    
     
      
       2
       ⁢
       π
      
     
     ⁢
     σ
    
   
   ⁢
   
    e
    
     -
     
      
       
        (
        
         x
         -
         μ
        
        )
       
       2
      
      
       2
       ⁢
       
        σ
        2, is established based on the difference data, where σ is a standard deviation, μ is the mean value, and the measurement threshold δ is taken as f(x=μ−3σ); and
7b) comparing the difference between each adjacent temporal data with the measurement threshold δ;
if the difference between adjacent temporal data is less than the measurement threshold δ, the temporal data with the smallest value is retained and the other temporal data are deleted; and
if the difference between the adjacent temporal data is not less than the measurement threshold δ, the temporal data closest in value to the temporal data of the reference sensor is retained and the other temporal data is deleted.