Uniform weights are applied between rows on transmit. As will be described later, arbitrary weights can be applied, in software, on receive. Calibration leads to low antenna sidelobes, supports good null depths in azimuth and doppler, supports accurate RCS calculation, and supports range, azimuth and elevation metrics.
Calibration is required throughout the test program.
As a result it was normally the first thing accomplished following any system changes, and was done prior to missions and after all missions. The first step toward a complete calibration of the radar is to equalize the receive channels. Data collected from RCAL are used to generate channel equalization coefficients. These equalization coefficients are used in FIR filters to achieve the required IF channel match, and were applied to the recorded data in the conversion from .bfr to .mat format. To generate the ACAL coefficients, a signal is injected into the ACAL port and the data out of the receiver is collected from the PE .