Front-End Processing for Monopulse Doppler Radar

FEPMR is standing for Front-End and Doppler Processing for Monopulse Doppler Radar. It is a PCB at the frontier between the RF and the Digital Circuits for the radar AXIR. There are four channels, corresponding to the four squinted beams of the antenna ( Right, Left, Up and Down ). Each beam channel is processed in phase (I) and quadrature ( Q) real baseband signals. The eight video analog signals are amplified and then converted by 8 ADC ( Analog to Digital Converters ). Four Texas Instruments (TI) TMS320C50 dgital signal processors (DSPs) ( one for each beam channel ) are operating two major algorithms in cascade. ‰ A flexible FIR ( Finite Impulse Response ) Digital Filter with complex coefficients is first applied as a Digital Pulse Compressor to provide 16 range bins. AXIR transmitter is using a quadriphase sequence (1 up to 31 sub-pulses). Coefficients for the reference code are optimised by the Radar Manager ( project C ) to reduce the range side lobes. ‰ The second part implements three IIR ( Infinite Impulse Response ) Digital Filters, using also complex coefficients as a Doppler filter. These coefficients are dynamically computed by the Radar Manager ( project C ) as a function of the tracked target range and Doppler. An output time decimation is provided in accordance with the coherent and non-coherent integration process.