diff --git a/master/master/lib/gps.c b/master/master/lib/gps.c
--- a/master/master/lib/gps.c
+++ b/master/master/lib/gps.c
@@ -435,6 +435,7 @@ void parse_gps_transmission(void){
 		{
 			if (byte == ',' && skipBytes == 0) //discard this byte
 			{
+				altitude[numBytes] = 0x00;
 				skipBytes = 1;
 				setParserState(GGA_ALTITUDE);
 			}