Limitations of Traditional FFT-based Detection Methods in Land- mine Detection Sample Clauses

Limitations of Traditional FFT-based Detection Methods in Land- mine Detection. ‌ The NQR signals are expressed as decaying sinusoidal waves of the form sin(ω0t) exp−t/T2∗ , where ω0 is the NQR frequency specific to the substance and T2∗ is the signal decay time. Unfortunately, the weak NQR signal’s amplitude is about 4 · 10−15 T, which is at the thermal noise level [45]. In addition, the frequency range of interest is 0.5-5 MHz, which overlaps with the short-wave radio spectrum used in radio broadcast. Moreover, the environmental noise can be up to 35 dB larger than the NQR signal, which leads to low SNR. An example of the spectrum after applying FFT to NQR signals is depicted in Fig.