Considerations for the design of ground clutter cancelers for weather radar
Abstract
Effects of the ground clutter ring in the second trip area for velocity estimation are investigated. Beside unfavorable effects on weather signal due to range square advantage, the clutter poses a new problem when interlaced samples for assigning correct ranges to velocity estimates are used. The problem arises because signals that generate reflectivity estimates for power comparisons cannot be filtered in the same manner as signals from which velocity estimates are generated. Therefore, comparison of powers in the reflectivity and velocity channels is required. Performance of a third order recursive elliptic filter is analyzed. The filter operates best in steady state, but it can also be made to operate in transient by properly initializing it memory elements. Performance on 8 simulated time samples shows that about 10 dB of clutter to signal margin is lost for power and 20 dB for mean velocity estimation; with such a small number of samples, the width estimate is useless. In order for spectrum width biases to be less than 1 m.s-1, a longer train of pulses must be employed on an initialized filter and several of the leading pulses must be used exclusively to further reduce the transients. These problems do not arise when canceling is done on an uninterrupted pulse train.
- Publication:
-
Final Report
- Pub Date:
- January 1982
- Bibcode:
- 1982nssl.rept.....Z
- Keywords:
-
- Bandpass Filters;
- Clutter;
- Doppler Radar;
- Estimates;
- Meteorological Radar;
- Velocity Measurement;
- Weather;
- Algorithms;
- Error Analysis;
- Pulses;
- Recursive Functions;
- Reflectance;
- Signal To Noise Ratios;
- Communications and Radar