WDTB Logo

DLOC Principles of Meteorological Doppler Radar:
WSR-88D Fundamentals

Quick Links: Tables | Figures | Animations | Equations | Acronyms | Contact WDTB

Previous Page: Maximum Unambiguous Range (Rmax) and PRF

Maximum Unambiguous Velocity (Vmax) and PRF

Not only is Rmax dependent on the PRF, but so is the maximum unambiguous velocity (Vmax) that the WSR-88D can determine for a volume of targets. By "unambiguous", we are referring to the WSR-88D's ability to accurately determine the largest Doppler radial velocity with its "first guess" or first pass through the data. The relationship between Vmax and PRF can be expressed mathematically as:

 
Equation 9.  Maximum unambiguous velocity (Vmax).  Click for long description.
 
or
    where PRF = pulse repetition frequency (s-1)
    PRT = pulse repetition time (s) = 1/PRF
    and greek symbol lambda = wavelength of energy transmitted.

For a PRF = 1000 pulses/sec (or PRT = .001 s) and greek symbol lambda = 0.105 m (or 10.5 cm), Vmax is 26.25 ms-1 (or ~ 51 kt).

Next Page: Doppler Dilemma