GOTO_MAXVEL = 1.5 # m/steps
GOTO_MAXDIST = 150 # m.
GOTODIST_TOL = 0.4  # m.
GOTOANG_TOL = 0.1 # rad.

# Core naviguation function to travel to a GPS target location.
function goto_gps(transf) {
	m_navigation = vec_from_gps(cur_goal.latitude, cur_goal.longitude, 0)
	#print(" has to move ", math.vec2.length(m_navigation), math.vec2.angle(m_navigation))
 	if(math.vec2.length(m_navigation)>GOTO_MAXDIST)
		log("Sorry this is too far (", math.vec2.length(m_navigation), " / ", GOTO_MAXDIST, " )")
	else if(math.vec2.length(m_navigation) < GOTODIST_TOL and math.vec2.angle(m_navigation) < GOTOANG_TOL){ # reached destination
			transf()
	} else {
		m_navigation = LimitSpeed(m_navigation, 1.0)
		#m_navigation = LCA(m_navigation)
		goto_abs(m_navigation.x, m_navigation.y, cur_goal.altitude - pose.position.altitude, 0.0)
	}
}

function LimitSpeed(vel_vec, factor){
  if(math.vec2.length(vel_vec)>GOTO_MAXVEL*factor)
  	vel_vec = math.vec2.scale(vel_vec, GOTO_MAXVEL*factor/math.vec2.length(vel_vec))
	return vel_vec
}