; =========================================================================
  pro cips_noise,signal,sva,noise,sza,crit_angle,                         $
                 noise_x1,noise_x2,noise_y1,noise_y2,                     $
                 noise_high_x1,noise_high_x2,noise_high_y1,noise_high_y2
; =========================================================================
; This procedure estimates the random uncertainty in the ability of a CIPS
; signal to be reproduced by a C Sigma model. 
; -------------------------------------------------------------------------
; SMB September 9, 2009
; SMB Modified October 23, 2009 - realized  that view angle correction is 
;   not nearly so large and can be ignored for now.
; -------------------------------------------------------------------------

;calculate a and b here (y = ax + b)
IF sza LE crit_angle THEN BEGIN
	IF noise_x2 NE -999. THEN BEGIN
		a = (noise_y2 - noise_y1)/(noise_x2 - noise_x1)
		b = noise_y2 - a*noise_x2
		value = a*sza + b
	ENDIF ELSE 	value = 0.02
ENDIF ELSE BEGIN
	IF noise_high_x2 NE -999. THEN BEGIN
		a = (noise_high_y2 - noise_high_y1)/(noise_high_x2 - noise_high_x1)
		b = noise_high_y2 - a*noise_high_x2
		value = a*sza + b 
	ENDIF ELSE value = 0.02
ENDELSE		

first=((signal*value)>1.0)

factor=((7./2. - 1.0)/(60.-40.)*(sva-40.) + 1.)>1.0

noise=first * factor

return
end