A GNSS receiver having an IF process engine is disclosed. The IF process engine provides a plurality of carriers with different frequencies and down converts IF signals into baseband signals by using the carriers in a time division multiplex (TDM) schedule. The IF process engine has a local oscillator part for generating the carriers with different frequencies; an IF down-converter for respectively mixing the IF signal with the carriers generated by the local oscillator part to generate IF removed signal segments; a time division multiplex (TDM) controller for scheduling the respective mixing operations of the IF down-converter for the IF signal with the respective carriers; and a buffer for storing the IF removed signal segments generated by the IF down-converter.