So you are looking for a tool that can keep you connected with your friends and team members outdoors even when cell service is not available? goTele is just the tool for the job. It allows you to keep track of your team in real-time and compare the location of up to 30 members. Users will also be able to send a SOS signal when in trouble.
goTele has a working range of 3.1 miles. Its app lets you create geo-fences, receive SOS signals, and share your location. The device is water resistant and connects to your smartphone through Bluetooth-LE.[where to get it]