Doppler shift


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Doppler shift

See Doppler effect.

Doppler shift

[′däp·lər ‚shift]
(physics)
The amount of the change in the observed frequency of a wave due to Doppler effect, usually expressed in hertz. Also known as Doppler frequency.

Doppler shift

Doppler shift
Doppler effect in moving receiver.
In airborne Doppler radar, a transmitter which, by means of a directional antenna, radiates energy toward the ground. This results in a situation in which both the transmitter and the receiver are moving relative to the ground; consequently the original frequency is changed twice. The difference between transmitted and received frequencies is known as the Doppler shift and is very nearly proportional to the relative motion between the aircraft and the ground along the direction of the radar beam. A moving target will cause the frequency of the echo signal to increase if it is approaching the radar or decrease if it is receding from the radar. Since the Doppler frequency shift is proportional to radial velocity, a radar system that measures such a shift in frequency can also provide the radial velocity of a target. The Doppler frequency shift also is used to separate moving targets from stationary ones even when the undesired clutter power might be much greater than the power of echo from the targets. Also called the Doppler effect.
References in periodicals archive ?
D] are the length of one OFDM symbol and the discrete length of Doppler shift, respectively.
A new method for estimating the Doppler shift and time delay of the overlapping echoes was presented by Qi et al.
The device measures a Doppler shift when movement beneath the probe is detected.
In Sections 3-4, the analytical formulas for Doppler shift and bandwidth are derived when the effects of large-scale waves shadow and curvature are also taken into account.
Higher frequencies are impacted more by Doppler shift than are lower frequencies; thus, signals can suffer significant spectral compression when platforms are traveling at velocities common to space missions.
In this case the correlation coefficient could be calculated as cross-correlation of the measured and prerecorded signal spectrums in the possible Doppler shift area
He begins with special relativity, including Lorentz transformations and the Doppler shift.
As an example of what becomes possible, French amateur Christian Buil was able to use the new spectrograph to measure the tiny Doppler shift produced by the planet orbiting Tau Bootes from his urban apartment balcony.
For example, if an airplane flying over a humvee was transmitting signals to the ground, the link would be affected by high Doppler shift rates and varying range delays that the humvee's receiver would need to track.
In addition, STK sets up the T400CS so it that can produce exact range delay, Doppler shift, range attenuation, AWGN (additive white Gaussian noise), and fading for the specified scenario.
We have considered the worst case scenario to evaluate the impact of Doppler shift.