A tracking system comprising: a radio frequency (RF) signal circulator; an iridium modem coupled to first port of the circulator; an antenna coupled to second port of the circulator, wherein the circulator passes a signal transmitted by the modem to the antenna when the switch is switched to a first mode; a low noise amplifier (LNA) coupled to third port of the circulator, wherein the circulator passes RF signals received from the antenna to the LNA; a diplexer coupled to an output of the LNA; a GNSS receiver coupled to a first output of the diplexer through a GNSS filter; an iridium filter coupled to a second output of the diplexer; wherein the switch couples the iridium filter to the modem when the iridium modem is in a receiving mode, and wherein the switch couples the modem to the first port when the modem is in a transmitting mode.