if (element_len > 4 || !element_len) return -1;
int decode_gpsquality(unsigned char *element, int element_len) {	// 0x34 GPS Data Quality - Fix, Validity, Sats, PDOP, HDOP, VDOP	int fixtype, validity, sats;	const char *fixstr[] = {"Unknown Fix", "No Fix", "2D Fix", "3D Fix"};	const char *validstr[] = {"Invalid", "Valid SPS", "Valid DGPS",						 "Valid PPS"};	if (element_len > 4 || !element_len) return -1;	fixtype = (element[0] & 0xc0) >> 6;	validity = (element[0] & 0x30) >> 4;	sats = (element[0] & 0x0f);	lprintf(T_OPENTRAC, "GPS: %s %s, %d sats", fixstr[fixtype],			validstr[validity], sats);	if (element_len > 1)		lprintf(T_OPENTRAC, " PDOP=%.1f", (float)element[1]/10);	if (element_len > 2)		lprintf(T_OPENTRAC, " HDOP=%.1f", (float)element[2]/10);	if (element_len > 3)		lprintf(T_OPENTRAC, " VDOP=%.1f", (float)element[3]/10);	lprintf(T_OPENTRAC, "\r\n");	return 0;}