Most tracking collars use satellite driven. The dog wears the collar that bounces the signal back to a hand held device the person carries. The long range devices can be up to 9 miles but that is open spaces. When you start to get into heavier foliage it is anywhere between 4-7 miles. The newer ones can also alert you to a dog in trouble and you can set a boundary for your dog and if they go out of that area it will alert you. If you have a multiple dog pack you can get ones that will track that and you are still only carrying one hand held device.