function [ve, vn] = rotadv(vx,vy, hdg)
% ROTADV - Rotates xy adv data into east north using the heading data.  
% [ve, vn] = rotadv(vx,vy, hdg)
%
% This is a 2-D rotation only, assumes no pitch or roll.

hdgrad = 2*pi*hdg/360;
ve = vx.*sin(hdgrad) - vy.*cos(hdgrad);
vn = vx.*cos(hdgrad) + vy.*sin(hdgrad);