fpbias_c.m

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%                             fpbias_c.m
%  Scope:   This MATLAB macro computes the value of a function used to determine
%           the parity bias (pbiasb) for the (dof+4) satellite case with Chi-
%           square distribution [1], when the degree-of-freedom (dof) is between 
%           2 and 10.
%  Usage:   xoutput = fpbias_c(x)
%  Description of parameters:
%           x       - input, scalar independent variable (lambda)
%           a       - input, global constant, normalized Chi-square threshold, 
%                     (dof dependent)
%           dof     - input, global constant, degree of freedom (2 <= dof <= 8)
%           pmd     - input, global constant, probability of missed detection
%           xoutput - output, computed value of the function; when 
%                     x = pbiasb then the value of the residual is 0.  
%  Reference: 
%           [1] Brown, R. G., Chin, G. V., GPS RAIM: Calculation of thresholds 
%               and protection radius using Chi-square methods - A geometric 
%               approach. RTCA Paper No. 491-94/SC159-584, Nov. 1994
%  Remark:  The value of a (normalized Chi-square threshold) is dof dependent
%           and can be a priori determined by using the program xfdnt.
%  External Matlab macros used: ncchi2_2.m, ncchi2_3.m, ncchi2_4.m, ncchi2_5.m,
%           ncchi2_6.m, ncchi2_7.m, ncchi2_8.m, ncchi2_9.m, ncchi2_10.m  
%  Last update: 04/13/00
%  Copyright (C) 1998-00 by LL Consulting. All Rights Reserved.

function  xoutput = fpbias_c(x)

global    a dof pmd 

%  Example:  for dof = 2 
%  a = 29.828;     %  upper integration limit corresponding to pfa = 3.33333e-7
%  pmd = 0.001;    %  probability of missed detection

%  Select the name of the non-central Chi-square m-file function (dof dependent)

name = ['ncchi2_' int2str(dof)];

%  Execute integration of non-central chi-square function (dof dependent) and 
%  determine the residual 

xoutput = pmd - quad8(name,0.,a,[],[],x);