QubeFlex handles a wide range of common space packets protocols as well as unformatted data, and helps Operators cope easily with the large
Doppler frequency shifts that are common to LEO satellites.
Here, L is the total number of possible propagation paths, [f.sub.Dj] is the [j.sup.th] path
Doppler frequency shift which creates ICI of the received signals, [h.sub.j] is the complex impulse response of the [j.sup.th] path and [[tau].sub.j] is the [j.sup.th] path time delay and [a.sub.n] is the complex path attenuation factor which gives the time varying complex amplitude, defined as the exponential term [mathematical expression not reproducible].
For example, when the L-band radar operating wavelength X > 15 cm, the speed of a conventional aircraft is less than Mach (Ma) 3; thus, the
Doppler frequency is less than 5.4 kHz, while the L-band signal bandwidth is several MHz.
This change in frequency is known as the
Doppler frequency shift.
Herein, the
Doppler frequency is estimated due to phase change undergone by the beat signal along a series of ramps of the FMCW signal, considering the null intra-pulse movement [6].
On this foundation, the current study analyzes and builds models for the principle of ultrasound reflection in drilling mud and explains the relationship between mud flow rate and
Doppler frequency shift under the condition of continuous nonoriented ultrasound reflection.
That is, when the velocity of a moving target is more than [V.sub.max]/K, the detected
Doppler frequency of this target is placed in the wrong frequency domain.
Compared with ambient noise and reverberation has its unique characteristics, one of the most important, the reverberation is caused by the emission signal, and has close relation with the environment, and the waveguide, therefore spectral properties of the reverberation and the target echo signal under the condition of the
Doppler frequency shift is correlation is very strong, and present a strong non-stationarity.