Index: trunk/BNC/bnchelp.html
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--- trunk/BNC/bnchelp.html	(revision 1888)
+++ trunk/BNC/bnchelp.html	(revision 1889)
@@ -414,5 +414,5 @@
 
 <p>
-Orbit corrections are provided in along-track, cross-track and radial components. These components are defined in the Earth-centered, Earth-fixed reference frame of the broadcast ephemerides. For an observer in this frame, the along-track component is parallel to the velocity vector and the cross-track component is perpendicular to the plane defined by the radial and along-track directions. The three components form a right-handed orthogonal system.
+Orbit corrections are provided in along-track, cross-track and radial components. These components are defined in the Earth-centered, Earth-fixed reference frame of the broadcast ephemerides. For an observer in this frame, the along-track component is aligned in both direction and sign with the velocity vector, the cross-track component is perpendicular to the plane defined by the satellite position and velocity vectors, and the radial direction is perpendicular to the along track and cross-track ones. The three components form a right-handed orthogonal system.
 </p>
 
