Although the average elevation of the GPS constellations of 20,200 kilometers (12,550 miles) may not be as high as communications satellites in geosynchronous orbits, they still have a long way to go. Considering this incredible distance and the size of the antenna on most GPS-equipped devices, it’s no wonder that the received signal is very weak. In fact, it is so weak that it is usually below the noise floor. Only with clever algorithms and a little bit of witchcraft can your mobile phone turn the whispers from the stars into something similar to useful information.
It is this vulnerability that makes these types of cheap GPS jammer possible. It doesn't take much to overwhelm legitimate signals. Keep in mind that a device like this will not try to imitate GPS satellites, it just sends out nonsense that is large enough that the real satellites can no longer be heard.
After turning on the jammer, we can clearly see how the already weak signal is completely cleared by the pattern sent by the device.
There is no competition. The legal signal is tens of thousands of miles away, and this thing screams in range. I haven't tested the range of this device, mainly because I don't want to open it longer than necessary, but it can do at least a few meters of work.
