A GPS does not replace compass and map and neither the need for an experienced and professional Kaokoland tour guide.
Several websites offers maps and other information.
Note that roads and tracks on maps do not always correspond with reality on ground zero. This tour was not a commercial tourist safari. Tarred road from Oshakati to Ruacana, the last fuel stop before entering Kaokoland. Provision for 900km fuel reach . Gravel road and accessible off-road conditions .