The best in FPV since 2022

The so-called detection, which we define here, is to find the activities of FPV around. Your position may be D1, that is, FPV is coming for you; Or D2, FPV is just passing by. Low cost is generally applied in D1, that is, personal application. So we only consider the signal characteristics at D1.

There are many tricks for detection, which are mainly divided into active and passive. Active radar equipment generally refers to radar equipment. Generally, its price is extremely high (relative to FPV cost), and it has certain deployment requirements, so it is generally not suitable for low-cost detection. Passive detection receives the signal sent by FPV itself. If the detection equipment finds and receives the signal in the feature library, it is considered that there is FPV activity around. Passive detection technology also has high cost and high spatial-temporal resolution solutions, but there are also routes that are suitable for low cost and miniaturization. We will only discuss passive detection.

Due to the limitation of cost and delay, FPV image transmission is mostly analog image transmission, and digital image transmission is few and far between. Therefore, accurate signal differentiation can be made by analyzing the radio modulation format of analog image transmission. There is no way for digital image transmission, and it can also be detected under the condition of extremely low signal-to-noise ratio by distinguishing the cross-correlation of digital signal synchronization words.

Some mainstream companies' larger equipment already has similar functions. However, this function is not omnipotent, and the signal library needs to be updated in time with the update of UAV equipment. If the signal is not in the library, it will be missed.

Some UAV detection equipment also supports decoding video streams, mainly for analog signals. This is because analog video signals are not encrypted and have a fixed format, so this function is not complicated. Just put a normal receiver in it, and even bring its own frequency scanning.

But I don't think it's meaningful to decode FPV signals. Because in this special case, FPV is one-off and will not return to the starting point in the future, decoding video stream will not provide more available information than early warning.