function [east,north,up] = pod2earth(u,v,w,tiltx,tilty,compass)

%  pod2earth -- rotate velocity from BASS to earth coordinates
% 
%      u,v,w are velocity in the Bass pod coordinates:
%              u from axes B, D
%              v from axes A, C
%              w is upward.
%      tiltx, tilty, and compass are angles in radians:
%              tiltx is between the u direction and horizontal
%              tilty is between the v direction and horizontal
%              compass is between the u direction and earth north.
%      east, north, up are the velocity components in earth
%              coordinates
%                               Fran Hotchkiss, December 18, 1997
%  Modified 25 June 1998 to use right-hand-rule definition of 
%      tilt directions.  If right hand thumb is in direction of
%      u velocity, a positive y-tilt is in the direction indicated
%      by the fingers.  If right hand thumb is in direction of
%      v velocity, a positive x-tilt is in the direction indicated
%      by the fingers.  FSH


costx = cos(tiltx);
sintx = sin(tiltx);
costy = cos(tilty);
sinty = sin(tilty);
coscp = cos(compass);
sincp = sin(compass);

u2 = u .* costx + w .* sintx;
v2 = v .* costy - w .* sinty;
up = w .* costx .* costy - u .* sintx + v .* sinty;

north = u2 .* coscp + v2 .* sincp;
east  = u2 .* sincp - v2 .* coscp;