Two-channel monopulse tracking receiver for onboard antenna tracking system

The advance communication satellites, having narrow spot beams, require an automatic antenna pointing mechanism to maintain the spot beam coverage over the specified area. The monopulse tracking system is a popular choice, where the required tracking accuracy is better than 1/10th of antenna beam width. The two-channel monopulse tracking receiver is an essential subsystem of two-channel monopulse tracking system. The receiver is realized using coherent detection technique for better noise performance. The phase lock loop (PLL), and automatic gain control (AGC) loop are the two major building blocks of the receiver. The receiver has been developed and tested with the tracking chain of GSAT-4 satellite. This paper presents specifications, design, implementation issues and performance of the receiver.