Method and arrangement for removing ground clutter
OwnerJorn Sierwaldinventor
Life of this patent
Estimating the term…
Abstract
A digital radar receiver generates the input signal which is a stream of complex numbers. The input signal is rearranged and sorted by measurement volumes, resulting in Doppler data vectors. Doppler data vectors are filtered using a number of different digital filters. The output Doppler data vectors of the filters together with the original Doppler data vector are the candidate signals. Each candidate signal is analyzed using several criteria in order to find the one signal which is most likely to be caused by precipitation and has the ground clutter removed by the filtering. The selected signal is then used to calculate the meteorological products. The selected signal is also used to derive a velocity value or velocity distribution while taking into account the effects of the filtering performed earlier.
Claims12
A method for converting radar signal into a number of meteorological products such as reflectivity, velocity, rainfall estimate, copolar differential phase and/or velocity moments, comprising:
- providing an input signal that represents the radar echoes received from a number of measurement volumes,
- for each measurement volume, deriving a number of candidate signals, which comprise the original Doppler data vector received from that measurement volume and a number of filtered versions of the original Doppler data vector;
- each of the said filtered versions being results of filtering performed either in the time domain or in the spectral domain, or any combination thereof,
- selecting from said candidate signals the one that best matches a set of predetermined criteria or rejecting the said candidate signals as not fulfilling the criteria, with criteria comprising of characteristics of a precipitation-originated signal and/or sand or dust-originated signal and/or biological scatter-originated signal and/or an additional set of criteria with known characteristics, and
- deriving and outputting a number of said meteorological products for that measurement volume from the selected candidate signal, if the said candidate signal exists.
A signal processing apparatus for converting a radar signal into a number of meteorological products such as reflectivity, rainfall estimate, copolar differential phase and velocity moments, comprising:
- a storage configured to store an input signal that represents the radar echoes received from a number of measurement volumes,
- a filter bank configured to derive, for each measurement volume, a number of candidate signals, which comprise the original Doppler data vector received from that measurement volume as well as filtered versions of said original Doppler data vector,
- a signal evaluator configured to select from said candidate signals the one that best matches a set of predetermined criteria or rejects the said candidate signals as not fulfilling the criteria, with criteria comprising of characteristics of a precipitation-originated signal and/or sand or dust-originated signal and/or biological scatter-originated signal and/or an additional set of criteria with known characteristics, and
- a formatter configured to derive and output a number of said meteorological products, such as reflectivity, velocity value and/or velocity distribution, for a given measurement volume from the selected candidate signal.
A computer program product, comprising, stored on a nonvolatile computer-readable medium, computer-readable instructions that, when executed by a processor or processors, cause the implementation of a method comprising:
- providing an input signal that represents the radar echoes received from a number of measurement volumes,
- for each measurement volume, deriving a number of candidate signals, which comprise the original Doppler data vector received from that measurement volume and a number of filtered versions of the original Doppler data vector;
- each of the said filltered versions being results of filltering performed either in the time domain or in the spectral domain, or any combination thereof,
- selecting from said candidate signals the one that best matches a set of predetermined criteria or rejecting the said candidate signals as not fulfilling the criteria, with criteria comprising of characteristics of a precipitation-originated signal and/or sand or dust-originated signal and/or biological scatter-originated signal and/or an additional set of criteria with known characteristics, and
- a formatter configured to derive and output a number of said meteorological products, such as reflectivity, velocity value and/or velocity distribution, for a given measurement volume from the selected candidate signal.
Dependencies are inferred from the claim text.