Patent ID: 11885890
Assignee: U-BLOX AG
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 12:
13. An apparatus for global navigation satellite system (GNSS) measurements, the apparatus comprising:
a receiver configured to receive a GNSS signal and process the received signal for the measurements; and
a processor configured to:
specify a prior probability density P(x) of a state x;
specify a system model h(x) that relates the state x to observables z of the measurements;
quantify quality metrics q associated with the measurements;
specify a non-Gaussian residual error probability density model ƒ(r|θ, q) and fitting model parameters θ using a set of experimental data, where r is the residual error;
define a posterior probability density P(x|z, q, θ); and
estimate the state x; and
compute a protection level of a position estimate by integrating the posterior probability density P(x|z, q, θ) over the state x,

wherein defining the posterior probability density is based on the formula:, P
   ⁡
   (
   
    
     x
     |
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    ,
    q
    ,
    θ
   
   )
  
  ∝
  
   
    P
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    (
    x
    )
   
   ⁢
   
    
     ∏
     i
    
    
     f
     ⁡
     (
     
      
       
        
         z
         i
        
        -
        
         
          h
          i
         
         (
         x
         )
        
       
       |
       θ
      
      ,
      
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       i
      
     
     )
    
   
  
 

where i is a natural number.