Measurement based FHSS–type Drone Controller Detection at 2.4GHz: An STFT Approach

Abstract

The applications of the unmanned aerial vehicles (UAVs) increase rapidly in everyday life, thus detecting the UAVs and/or its pilot is a crucial task. Many UAVs adopt frequency hopping spread spectrum (FHSS) technology to efficiently and securely communicate with their radio controllers (RCs) where the signal follows a hopping pattern to prevent harmful interference. In order to realistically distinguish the frequency hopping (FH) RC signals, one should consider the real-world radio propagation environment since many UAVs communicate with RCs from a far distance in which signal faces both slow and fast fading phenomenons. Therefore, in this study different from the literature, we consider a system that works under realconditions by capturing over-the-air signals at hilly terrain suburban environments in the presence of foliages. We adopt the short-time Fourier transform (STFT) approach to capture the hopping sequence of each signal. Furthermore, time guards associated with each hopping sequence are calculated using the autocorrelation function (ACF) of the STFT which results in differentiating the each UAV RC signal accurately. In order to validate the performance of the proposed method, the results of normalized mean square error (MSE) respect to different signal-to-noise ratio (SNR), window size and Tx-Rx separation values are given.

Drone Detection Sensor With Continuous 2.4 GHz ISM Band Coverage Based on Cost-Effective SDR Platform

“…The simplified architecture of the proposed sensor that provides direct data input for drone detection methods proposed in [20], [22]- [24] is demonstrated in Fig. 3.…”

“…The RF capture device can be based on high frequency oscilloscope [18], spectrum analyzer [20] or SDR platform [21]- [24]. Although both, oscilloscope and spectrum analyzer, offers high accuracy and fulfills bandwidth requirement, they are designed for rather a laboratory use.…”

“…Nevertheless, the full-band approach enhances spectrogram dataset accuracy and opens up new opportunities for detection algorithms. In addition, the methodology described in [20], based on Short Time Fourier Transform (STFT), cannot be applied without observing the entire 2.400 GHz to 2.483 GHz frequency range continuously. There are some high-performance SDRs on the market that offers 120 MHz instantaneous bandwidth and PCIe or 10 GigE interface [26].…”

A New Frequency Hopping Signal Detection of Civil UAV Based on Improved K-Means Clustering Algorithm

“…Up till now, there are many researches for how to obtain signal threshold  [23][24][25]. In [23], an automatic algorithm extraction of the signal components (useful information) from the noisy mixture is based on the time-frequency distribution segment to a fixed number of data classes is proposed, which depends on the differences in the time frequency structures of noise and signal components.…”

“…Time domain detection methods include image analysis, energy detection, correlation detection, etc. [23][24][25][26][27][28].…”