In addition, mainly from the military point of view, it is a strategy to open idle resources to the whole world. The free strategy of GPS will definitely make almost all the later developed positioning systems in the world unable to compete with it. Even if it is free and open, the technical maturity is not as good as GPS. GPS forms a de facto monopoly, forcing the whole world to use and rely on GPS.
On this basis, using GPS is equivalent to exposing the location privacy to the US military. And the us military has the right to intervene and stop using it. In the event of war, the US military can use intervention.
Without increasing the budget on the original basis, it has achieved great military strategic advantages by the way. Free use for the whole world can be said to be very profitable for the US military.
There are several mistakes in the answer upstairs. The U.S. military has no patent for registering GPS. The reason is very simple, because patents disclose technical details to the society, and the purpose of setting up patents is to make profits. The US military did not open GPS for profit, and did not apply for a patent, because the technical details of GPS could not be disclosed. Moreover, in order to apply for a patent to take effect, it is necessary to apply to each country separately. It is impossible for other countries to let the US military muddle through the technical details. The principle, signal data and data format of GPS are all open, and only the details of satellite and control system are confidential. But this is enough for civil positioning that only receives signals. Anyone can be a receiver. The GPS in the mobile phone is basically not an independent module, but mostly integrated with the baseband. When producing mobile phone baseband, several chip factories brought it, such as Cisco, Qualcomm, MediaTek, Hisilicon and so on.
In addition, GPS is a positioning system, and the data received from satellites are only latitude, longitude and altitude, which is a universal format all over the world and does not need special decryption and decoding. It has nothing to do with map data and navigation technology, and the cost of map and navigation has nothing to do with GPS positioning.
It is not said that the US military provides more accurate services in GPS. Our daily vehicle positioning can cooperate with navigation to achieve very accurate vehicle scheduling. Some measuring instruments used in industrial production, such as building tower cranes, are also very accurate. For the US military, if it is easy to obtain higher accuracy, there is no need to hide it from the public and then provide charging services. Obviously, if you learn from other countries' positioning systems to encrypt data and then sell decryption cards, you can sit on the ground and suck money, and you will invest more manpower and material resources to do such a laborious thing? What's more, if you want to increase the accuracy of the existing GPS, the principle is also very simple. It can increase antenna power and connect more satellites. The more satellites connected, the more accurate.