Who says Beidou cannot be positioned independently?
However, some people call me: "GPS is the main positioning, your home is only used to make GPS Beidou number, he did not have the ability to independently locate, without GPS your home is not." Waiting for you to say It's QZSS. Can't you use the country to spend money on this?
The reason is obvious, but it is not easy to prove. Why? For the mobile phone, the satellite receiving channel hardware is objectively existed. Unless the chip's underlying control instructions are opened to the outside world, the so-called “off GPS” is not a real closure of the receiving channel, but it does not take GPS positioning results and cannot fully guarantee the requirements for verification. "Beidou can be independently positioned", after all, the underlying algorithm of the chip is uncontrollable, what if the person who designs the navigation chip must steal the GPS guidance?
The proof method is to use a special kind of microwave darkroom - GNSS test darkroom!
The principle of the GNSS test darkroom is similar to that of an ordinary microwave darkroom. All the electromagnetic wave signals are shielded. The signal emitted from the darkroom will not reflect on the wall, but only the frequency band of the key protection is different. Compared to the microwave anechoic chamber of the test radar or large array antenna, the GNSS test darkroom is not too large because the size of the GNSS receiver is not large. The most important difference is that the GNSS navigation signal simulator and the complete test evaluation system have This set of things can simulate the situation of a GNSS satellite at any point on the earth. What signals you want to send are what signals you want to send, where you want to send your hair, you want to move, you want to stop, you can stop and you can test your device. The positioning results are evaluated and the authoritative accuracy test results are given.
In the darkroom, it can be ensured that only BeiDou satellite signals can be received. The power is also calibrated to be consistent with the open air. It can eliminate all uncontrollable factors. If it can be located in this case, it can prove that the mobile phone does have " Beidou's ability to independently position itself. What's the result?
Of course there is no suspense:
Received ten satellites are all Beidou, 9 are involved in positioning, there is no GPS, there is no assistance, Beidou satellites are really "independent positioning". With Beidouzhi in the world, after the Compass Three Generations Network was completed in 2020, we could rely on Compass to independently locate at any point on the planet.