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. HT printscreen of the receiver Xbee serial output

  • \$\begingroup\$ Have you looked at the data as it goes into the xbee? As it comes out of the GPS? Have you put an oscilloscope on it? \$\endgroup\$ – John U Mar 4 '14 at 12:16
  • \$\begingroup\$ this look like a byte/ASCII decoding issue. how are you decoding your xbee packet? Are you in the AT or API mode? \$\endgroup\$ – vrleboss Mar 4 '14 at 21:43
  • \$\begingroup\$ @vrleboss The Xbee is in the AT mode. The baud rate of the Xbees are set to 9600, the same with the GPS. \$\endgroup\$ – roseannvalorie Mar 6 '14 at 5:35

Garbage characters on a UART line usually means that the baud rate in not setup correctly.


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