Overlapping-based Radio Signal Processing for SDF Location Method

Frequency Instability Impact of Low-Cost SDRs on Doppler-Based Localization Accuracy

“…Table 6 concludes the SDF location accuracy obtained in the empirical studies. Empirical research was carried out for measurement scenarios located on a university campus using a car [30,[53][54][55] or UAV [56]. In the first experiments [30,53,54], the obtained location errors were very small, which resulted from the fact that the emitter position was determined based on all DFSs measured along the measurement route, i.e., the emitter position was estimated based on the whole Doppler curve.…”

“…In the first experiments [30,53,54], the obtained location errors were very small, which resulted from the fact that the emitter position was determined based on all DFSs measured along the measurement route, i.e., the emitter position was estimated based on the whole Doppler curve. In recent studies [55,56], the emitter position was determined based on DFS measured during the acquisition time window of approximately 30 s. The located signal source emitted a harmonic [53][54][55] or modulated signal, i.e., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), or 16 quadrature amplitude modulation (16 QAM) [30,56]. In this case of modulated signals, DFSs were determined based on the estimation of the carrier signal determined by raising the signal to the second or fourth power.…”

“…Under this grant, UAVs carrying out COMINT tasks in the field of spectrum monitoring and locating radio emitters will be developed. For the second task, we plan to use a Doppler-based localization method called the signal Doppler frequency (SDF) [27,28]. On the other hand, the localization of radio emitters is widely used in the civil market, including, among others, in positioning wireless network users or users who illegally use licensed frequency bands.…”

“…Measurements [30] have shown that using ground vehicles introduces limitations to the localization procedure, including difficulties in maintaining a constant speed, changing the sensor motion direction, and multipath propagation resulting from the neighborhood of terrain obstacles [32]. The use of UAVs [27,28] or watercrafts [33] for this purpose provides greater opportunities, provides greater movement freedom, and improves propagation conditions by minimizing the impact of unfavorable phenomena.…”

“…This effect translates into larger localization errors for the long-range case. Therefore, when planning the mission, the appropriate direction of the sensor movement trajectory should be considered [27,33], or the value of the signal acquisition window should be adjusted [28].…”