We're building a tracking system using Xbee and GPS. Wherein the GPS data is transmitted using the Tx Xbee and received with the Rx Xbee. We've supplied a 3.3V to both the Xbee and GPS (SKM53 by skylab) in the transmitter side, we also connected TX-RX and RX-TX pin of gps and xbee. On the receiver side, we also supplied the rx xbee with 3.3 v, we used a USB-UART converter to read GPS data that is received by the receiver xbee. The problem is we cannot recover the NMEA sentences being transmitted. There are garbage characters included in the NMEA sentences. Any suggestions on how to fix this? thank you in advance.