Introduction to low-cost FPV reconnaissance

Introduction to detection

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.

The equipment in the video and the equipment in the picture should be of the same product. We can see that this product mainly captures the FPV radio signal and estimates the distance through the intensity, so as to carry out the early warning of FPV. Because the image transmission signal is the signal with the highest transmission power on FPV, it can also be regarded as the product's early warning by capturing the image transmission signal of FPV.

I guess, this product is roughly equivalent to a sweep spectrum analyzer, which filters the noise through the fast switching of LO frequency, and then quantifies the energy through a power meter to scan the signal strength in a wide bandwidth range, and will give an alarm when it is triggered to the limit. That is to say, this product is actually similar to the spectrometer shown below.