Thatcham Approved: All of our trackers are Thatcham Authorised, that means that they have already been issue to stringent security screening by Thatcham, as a way to ascertain their basic safety and efficiency. A GPS module communicates continually with satellites to ascertain its precise location, when GSM engineering achieves this https://medium.com/@trackerfit11/caravan-trackers-and-why-they-matter-for-theft-protection-dd44f62fcad7