altos: Add U-Blox GPS driver

Uses binary mode.

Signed-off-by: Keith Packard <keithp@keithp.com>

4 files changed, 1280 insertions, 1 deletions

diff --git a/src/drivers/ao_gps_ublox.c b/src/drivers/ao_gps_ublox.c
new file mode 100644
index 00000000..32405ea5
--- /dev/null
+++ b/src/drivers/ao_gps_ublox.c
@@ -0,0 +1,626 @@
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#ifndef AO_GPS_TEST
+#include "ao.h"
+#endif
+
+#include "ao_gps_ublox.h"
+
+__xdata uint8_t ao_gps_mutex;
+__pdata uint16_t ao_gps_tick;
+__xdata struct ao_telemetry_location	ao_gps_data;
+__xdata struct ao_telemetry_satellite	ao_gps_tracking_data;
+
+static const char ao_gps_set_nmea[] = "\r\n$PUBX,41,1,3,1,57600,0*2d\r\n";
+
+const char ao_gps_config[] = {
+
+};
+
+struct ao_ublox_cksum {
+	uint8_t	a, b;
+};
+
+static __pdata struct ao_ublox_cksum ao_ublox_cksum;
+static __pdata uint16_t ao_ublox_len;
+
+#ifndef ao_ublox_getchar
+#define ao_ublox_getchar	ao_serial1_getchar
+#define ao_ublox_putchar	ao_serial1_putchar
+#define ao_ublox_set_speed	ao_serial1_set_speed
+#endif
+
+#define ao_ublox_byte()	((uint8_t) ao_ublox_getchar())
+
+static inline void add_cksum(struct ao_ublox_cksum *cksum, uint8_t c)
+{
+	cksum->a += c;
+	cksum->b += cksum->a;
+}
+
+static void ao_ublox_init_cksum(void)
+{
+	ao_ublox_cksum.a = ao_ublox_cksum.b = 0;
+}
+
+static void ao_ublox_putchar_cksum(uint8_t c)
+{
+	add_cksum(&ao_ublox_cksum, c);
+	ao_ublox_putchar(c);
+}
+
+static uint8_t header_byte(void)
+{
+	uint8_t	c = ao_ublox_byte();
+	add_cksum(&ao_ublox_cksum, c);
+	return c;
+}
+
+static uint8_t data_byte(void)
+{
+	--ao_ublox_len;
+	return header_byte();
+}
+
+static char __xdata *ublox_target;
+
+static void ublox_u16(uint8_t offset)
+{
+	uint16_t __xdata *ptr = (uint16_t __xdata *) (ublox_target + offset);
+	uint16_t val;
+
+	val = data_byte();
+	val |= data_byte () << 8;
+	*ptr = val;
+}
+
+static void ublox_u8(uint8_t offset)
+{
+	uint8_t __xdata *ptr = (uint8_t __xdata *) (ublox_target + offset);
+	uint8_t val;
+
+	val = data_byte ();
+	*ptr = val;
+}
+
+static void ublox_u32(uint8_t offset) __reentrant
+{
+	uint32_t __xdata *ptr = (uint32_t __xdata *) (ublox_target + offset);
+	uint32_t val;
+
+	val = ((uint32_t) data_byte ());
+	val |= ((uint32_t) data_byte ()) << 8;
+	val |= ((uint32_t) data_byte ()) << 16;
+	val |= ((uint32_t) data_byte ()) << 24;
+	*ptr = val;
+}
+
+static void ublox_discard(uint8_t len)
+{
+	while (len--)
+		data_byte();
+}
+
+#define UBLOX_END	0
+#define UBLOX_DISCARD	1
+#define UBLOX_U8	2
+#define UBLOX_U16	3
+#define UBLOX_U32	4
+
+struct ublox_packet_parse {
+	uint8_t	type;
+	uint8_t	offset;
+};
+
+static void
+ao_ublox_parse(void __xdata *target, const struct ublox_packet_parse *parse) __reentrant
+{
+	uint8_t	i, offset;
+
+	ublox_target = target;
+	for (i = 0; ; i++) {
+		offset = parse[i].offset;
+		switch (parse[i].type) {
+		case UBLOX_END:
+			return;
+		case UBLOX_DISCARD:
+			ublox_discard(offset);
+			break;
+		case UBLOX_U8:
+			ublox_u8(offset);
+			break;
+		case UBLOX_U16:
+			ublox_u16(offset);
+			break;
+		case UBLOX_U32:
+			ublox_u32(offset);
+			break;
+		}
+	}
+}
+
+/*
+ * NAV-DOP message parsing
+ */
+
+static struct nav_dop {
+	uint16_t	pdop;
+	uint16_t	hdop;
+	uint16_t	vdop;
+} nav_dop;
+
+static const struct ublox_packet_parse nav_dop_packet[] = {
+	{ UBLOX_DISCARD, 6 },					/* 0 GPS Millisecond Time of Week, gDOP */
+	{ UBLOX_U16, offsetof(struct nav_dop, pdop) },		/* 6 pDOP */
+	{ UBLOX_DISCARD, 2 },					/* 8 tDOP */
+	{ UBLOX_U16, offsetof(struct nav_dop, vdop) },		/* 10 vDOP */
+	{ UBLOX_U16, offsetof(struct nav_dop, hdop) },		/* 12 hDOP */
+	{ UBLOX_DISCARD, 4 },					/* 14 nDOP, eDOP */
+	{ UBLOX_END, 0 }
+};
+
+static void
+ao_ublox_parse_nav_dop(void)
+{
+	ao_ublox_parse(&nav_dop, nav_dop_packet);
+}
+
+/*
+ * NAV-POSLLH message parsing
+ */
+static struct nav_posllh {
+	int32_t		lat;
+	int32_t		lon;
+	int32_t		alt_msl;
+} nav_posllh;
+
+static const struct ublox_packet_parse nav_posllh_packet[] = {
+	{ UBLOX_DISCARD, 4 },						/* 0 GPS Millisecond Time of Week */
+	{ UBLOX_U32, offsetof(struct nav_posllh, lon) },		/* 4 Longitude */
+	{ UBLOX_U32, offsetof(struct nav_posllh, lat) },		/* 8 Latitude */
+	{ UBLOX_DISCARD, 4 },						/* 12 Height above Ellipsoid */
+	{ UBLOX_U32, offsetof(struct nav_posllh, alt_msl) },		/* 16 Height above mean sea level */
+	{ UBLOX_DISCARD, 8 },						/* 20 hAcc, vAcc */
+	{ UBLOX_END, 0 },						/* 28 */
+};
+
+static void
+ao_ublox_parse_nav_posllh(void)
+{
+	ao_ublox_parse(&nav_posllh, nav_posllh_packet);
+}
+
+/*
+ * NAV-SOL message parsing
+ */
+static struct nav_sol {
+	uint8_t		gps_fix;
+	uint8_t		flags;
+	uint8_t		nsat;
+} nav_sol;
+
+static const struct ublox_packet_parse nav_sol_packet[] = {
+	{ UBLOX_DISCARD, 10 },						/* 0 iTOW, fTOW, week */
+	{ UBLOX_U8, offsetof(struct nav_sol, gps_fix) },		/* 10 gpsFix */
+	{ UBLOX_U8, offsetof(struct nav_sol, flags) },			/* 11 flags */
+	{ UBLOX_DISCARD, 35 },						/* 12 ecefX, ecefY, ecefZ, pAcc, ecefVX, ecefVY, ecefVZ, sAcc, pDOP, reserved1 */
+	{ UBLOX_U8, offsetof(struct nav_sol, nsat) },			/* 47 numSV */
+	{ UBLOX_DISCARD, 4 },						/* 48 reserved2 */
+	{ UBLOX_END, 0 }
+};
+
+#define NAV_SOL_FLAGS_GPSFIXOK		0
+#define NAV_SOL_FLAGS_DIFFSOLN		1
+#define NAV_SOL_FLAGS_WKNSET		2
+#define NAV_SOL_FLAGS_TOWSET		3
+
+static void
+ao_ublox_parse_nav_sol(void)
+{
+	ao_ublox_parse(&nav_sol, nav_sol_packet);
+}
+
+/*
+ * NAV-SVINFO message parsing
+ */
+
+static struct nav_svinfo {
+	uint8_t	num_ch;
+	uint8_t flags;
+} nav_svinfo;
+
+static const struct ublox_packet_parse nav_svinfo_packet[] = {
+	{ UBLOX_DISCARD, 4 },						/* 0 iTOW */
+	{ UBLOX_U8, offsetof(struct nav_svinfo, num_ch) },		/* 4 numCh */
+	{ UBLOX_U8, offsetof(struct nav_svinfo, flags) },		/* 5 globalFlags */
+	{ UBLOX_DISCARD, 2 },						/* 6 reserved2 */
+	{ UBLOX_END, 0 }
+};
+
+#define NAV_SVINFO_MAX_SAT	16
+
+static struct nav_svinfo_sat {
+	uint8_t	chn;
+	uint8_t svid;
+	uint8_t flags;
+	uint8_t quality;
+	uint8_t cno;
+} nav_svinfo_sat[NAV_SVINFO_MAX_SAT];
+
+static uint8_t	nav_svinfo_nsat;
+
+static const struct ublox_packet_parse nav_svinfo_sat_packet[] = {
+	{ UBLOX_U8, offsetof(struct nav_svinfo_sat, chn) },		/* 8 + 12*N chn */
+	{ UBLOX_U8, offsetof(struct nav_svinfo_sat, svid) },		/* 9 + 12*N svid */
+	{ UBLOX_U8, offsetof(struct nav_svinfo_sat, flags) },		/* 10 + 12*N flags */
+	{ UBLOX_U8, offsetof(struct nav_svinfo_sat, quality) },		/* 11 + 12*N quality */
+	{ UBLOX_U8, offsetof(struct nav_svinfo_sat, cno) },		/* 12 + 12*N cno */
+	{ UBLOX_DISCARD, 7 },						/* 13 + 12*N elev, azim, prRes */
+	{ UBLOX_END, 0 }
+};
+
+#define NAV_SVINFO_SAT_FLAGS_SVUSED		0
+#define NAV_SVINFO_SAT_FLAGS_DIFFCORR		1
+#define NAV_SVINFO_SAT_FLAGS_ORBITAVAIL		2
+#define NAV_SVINFO_SAT_FLAGS_ORBITEPH		3
+#define NAV_SVINFO_SAT_FLAGS_UNHEALTHY		4
+#define NAV_SVINFO_SAT_FLAGS_ORBITALM		5
+#define NAV_SVINFO_SAT_FLAGS_ORBITAOP		6
+#define NAV_SVINFO_SAT_FLAGS_SMOOTHED		7
+
+#define NAV_SVINFO_SAT_QUALITY_IDLE		0
+#define NAV_SVINFO_SAT_QUALITY_SEARCHING	1
+#define NAV_SVINFO_SAT_QUALITY_ACQUIRED		2
+#define NAV_SVINFO_SAT_QUALITY_UNUSABLE		3
+#define NAV_SVINFO_SAT_QUALITY_LOCKED		4
+#define NAV_SVINFO_SAT_QUALITY_RUNNING		5
+
+static void
+ao_ublox_parse_nav_svinfo(void)
+{
+	uint8_t	nsat;
+	nav_svinfo_nsat = 0;
+	ao_ublox_parse(&nav_svinfo, nav_svinfo_packet);
+	for (nsat = 0; nsat < nav_svinfo.num_ch && ao_ublox_len >= 12; nsat++) {
+		if (nsat < NAV_SVINFO_MAX_SAT) {
+			ao_ublox_parse(&nav_svinfo_sat[nav_svinfo_nsat++], nav_svinfo_sat_packet);
+		} else {
+			ublox_discard(12);
+		}
+	}
+}
+
+/*
+ * NAV-TIMEUTC message parsing
+ */
+static struct nav_timeutc {
+	uint16_t	year;
+	uint8_t		month;
+	uint8_t		day;
+	uint8_t		hour;
+	uint8_t		min;
+	uint8_t		sec;
+	uint8_t		valid;
+} nav_timeutc;
+
+#define NAV_TIMEUTC_VALID_TOW	0
+#define NAV_TIMEUTC_VALID_WKN	1
+#define NAV_TIMEUTC_VALID_UTC	2
+
+static const struct ublox_packet_parse nav_timeutc_packet[] = {
+	{ UBLOX_DISCARD, 12 },						/* 0 iTOW, tAcc, nano */
+	{ UBLOX_U16, offsetof(struct nav_timeutc, year) },		/* 12 year */
+	{ UBLOX_U8, offsetof(struct nav_timeutc, month) },		/* 14 month */
+	{ UBLOX_U8, offsetof(struct nav_timeutc, day) },		/* 15 day */
+	{ UBLOX_U8, offsetof(struct nav_timeutc, hour) },		/* 16 hour */
+	{ UBLOX_U8, offsetof(struct nav_timeutc, min) },		/* 17 min */
+	{ UBLOX_U8, offsetof(struct nav_timeutc, sec) },		/* 18 sec */
+	{ UBLOX_U8, offsetof(struct nav_timeutc, valid) },		/* 19 valid */
+	{ UBLOX_END, 0 }
+};
+
+static void
+ao_ublox_parse_nav_timeutc(void)
+{
+	ao_ublox_parse(&nav_timeutc, nav_timeutc_packet);
+}
+
+/*
+ * NAV-VELNED message parsing
+ */
+
+static struct nav_velned {
+	int32_t		vel_d;
+	uint32_t	g_speed;
+	int32_t		heading;
+} nav_velned;
+
+static const struct ublox_packet_parse nav_velned_packet[] = {
+	{ UBLOX_DISCARD, 12 },						/* 0 iTOW, velN, velE */
+	{ UBLOX_U32, offsetof(struct nav_velned, vel_d) },		/* 12 velD */
+	{ UBLOX_DISCARD, 4 },						/* 16 speed */
+	{ UBLOX_U32, offsetof(struct nav_velned, g_speed) },		/* 20 gSpeed */
+	{ UBLOX_U32, offsetof(struct nav_velned, heading) },		/* 24 heading */
+	{ UBLOX_DISCARD, 8 },						/* 28 sAcc, cAcc */
+	{ UBLOX_END, 0 }
+};
+
+static void
+ao_ublox_parse_nav_velned(void)
+{
+	ao_ublox_parse(&nav_velned, nav_velned_packet);
+}
+
+/*
+ * Set the protocol mode and baud rate
+ */
+
+static void
+ao_gps_setup(void)
+{
+	uint8_t	i, k;
+	ao_ublox_set_speed(AO_SERIAL_SPEED_9600);
+
+	/*
+	 * A bunch of nulls so the start bit
+	 * is clear
+	 */
+	for (i = 0; i < 64; i++)
+		ao_ublox_putchar(0x00);
+
+	/*
+	 * Send the baud-rate setting and protocol-setting
+	 * command three times
+	 */
+	for (k = 0; k < 3; k++)
+		for (i = 0; i < sizeof (ao_gps_set_nmea); i++)
+			ao_ublox_putchar(ao_gps_set_nmea[i]);
+
+	/*
+	 * Increase the baud rate
+	 */
+	ao_ublox_set_speed(AO_SERIAL_SPEED_57600);
+
+	/*
+	 * Pad with nulls to give the chip
+	 * time to see the baud rate switch
+	 */
+	for (i = 0; i < 64; i++)
+		ao_ublox_putchar(0x00);
+}
+
+void
+ao_ublox_putstart(uint8_t class, uint8_t id, uint16_t len)
+{
+	ao_ublox_init_cksum();
+	ao_ublox_putchar(0xb5);
+	ao_ublox_putchar(0x62);
+	ao_ublox_putchar_cksum(class);
+	ao_ublox_putchar_cksum(id);
+	ao_ublox_putchar_cksum(len);
+	ao_ublox_putchar_cksum(len >> 8);
+}
+
+void
+ao_ublox_putend(void)
+{
+	ao_ublox_putchar(ao_ublox_cksum.a);
+	ao_ublox_putchar(ao_ublox_cksum.b);
+}
+
+void
+ao_ublox_set_message_rate(uint8_t class, uint8_t msgid, uint8_t rate)
+{
+	ao_ublox_putstart(0x06, 0x01, 3);
+	ao_ublox_putchar_cksum(class);
+	ao_ublox_putchar_cksum(msgid);
+	ao_ublox_putchar_cksum(rate);
+	ao_ublox_putend();
+}
+
+/*
+ * Disable all MON message
+ */
+static const uint8_t ublox_disable_mon[] = {
+	0x0b, 0x09, 0x02, 0x06, 0x07, 0x21, 0x08, 0x04
+};
+
+/*
+ * Disable all NAV messages. The desired
+ * ones will be explicitly re-enabled
+ */
+
+static const uint8_t ublox_disable_nav[] = {
+	0x60, 0x22, 0x31, 0x04, 0x40, 0x01, 0x02, 0x32,
+	0x06, 0x03, 0x30, 0x20, 0x21, 0x11, 0x12
+};
+
+void
+ao_gps(void) __reentrant
+{
+	uint8_t			class, id;
+	struct ao_ublox_cksum	cksum;
+	uint8_t			i;
+
+	ao_gps_setup();
+
+	for (i = 0; i < sizeof (ublox_disable_mon); i++)
+		ao_ublox_set_message_rate(0x0a, ublox_disable_mon[i], 0);
+	for (i = 0; i < sizeof (ublox_disable_nav); i++)
+		ao_ublox_set_message_rate(0x01, ublox_disable_nav[i], 0);
+
+	/* Enable all of the messages we want */
+
+	/* DOP */
+	ao_ublox_set_message_rate(0x01, 0x04, 1);
+
+	/* POSLLH */
+	ao_ublox_set_message_rate(0x01, 0x02, 1);
+
+	/* SOL */
+	ao_ublox_set_message_rate(0x01, 0x06, 1);
+
+	/* SVINFO */
+	ao_ublox_set_message_rate(0x01, 0x30, 1);
+
+	/* VELNED */
+	ao_ublox_set_message_rate(0x01, 0x12, 1);
+
+	/* TIMEUTC */
+	ao_ublox_set_message_rate(0x01, 0x21, 1);
+	
+	for (;;) {
+		/* Locate the begining of the next record */
+		while (ao_ublox_byte() != (uint8_t) 0xb5)
+			;
+		if (ao_ublox_byte() != (uint8_t) 0x62)
+			continue;
+
+		ao_ublox_init_cksum();
+
+		class = header_byte();
+		id = header_byte();
+
+		/* Length */
+		ao_ublox_len = header_byte();
+		ao_ublox_len |= header_byte() << 8;
+
+		if (ao_ublox_len > 1023)
+			continue;
+
+		switch (class) {
+		case UBLOX_NAV:
+			switch (id) {
+			case UBLOX_NAV_DOP:
+				if (ao_ublox_len != 18)
+					break;
+				ao_ublox_parse_nav_dop();
+				break;
+			case UBLOX_NAV_POSLLH:
+				if (ao_ublox_len != 28)
+					break;
+				ao_ublox_parse_nav_posllh();
+				break;
+			case UBLOX_NAV_SOL:
+				if (ao_ublox_len != 52)
+					break;
+				ao_ublox_parse_nav_sol();
+				break;
+			case UBLOX_NAV_SVINFO:
+				if (ao_ublox_len < 8)
+					break;
+				ao_ublox_parse_nav_svinfo();
+				break;
+			case UBLOX_NAV_VELNED:
+				if (ao_ublox_len != 36)
+					break;
+				ao_ublox_parse_nav_velned();
+				break;
+			case UBLOX_NAV_TIMEUTC:
+				if (ao_ublox_len != 20)
+					break;
+				ao_ublox_parse_nav_timeutc();
+				break;
+			}
+			break;
+		}
+
+		if (ao_ublox_len != 0)
+			continue;
+
+		/* verify checksum and end sequence */
+		cksum.a = ao_ublox_byte();
+		cksum.b = ao_ublox_byte();
+		if (ao_ublox_cksum.a != cksum.a || ao_ublox_cksum.b != cksum.b)
+			continue;
+
+		switch (class) {
+		case 0x01:
+			switch (id) {
+			case 0x21:
+				ao_mutex_get(&ao_gps_mutex);
+				ao_gps_tick = ao_time();
+
+				ao_gps_data.flags = 0;
+				ao_gps_data.flags |= AO_GPS_RUNNING;
+				if (nav_sol.gps_fix & (1 << NAV_SOL_FLAGS_GPSFIXOK)) {
+					uint8_t	nsat = nav_sol.nsat;
+					ao_gps_data.flags |= AO_GPS_VALID;
+					if (nsat > 15)
+						nsat = 15;
+					ao_gps_data.flags |= nsat;
+				}
+				if (nav_timeutc.valid & (1 << NAV_TIMEUTC_VALID_UTC))
+					ao_gps_data.flags |= AO_GPS_DATE_VALID;
+				
+				ao_gps_data.altitude = nav_posllh.alt_msl / 1000;
+				ao_gps_data.latitude = nav_posllh.lat;
+				ao_gps_data.longitude = nav_posllh.lon;
+
+				ao_gps_data.year = nav_timeutc.year - 2000;
+				ao_gps_data.month = nav_timeutc.month;
+				ao_gps_data.day = nav_timeutc.day;
+
+				ao_gps_data.hour = nav_timeutc.hour;
+				ao_gps_data.minute = nav_timeutc.min;
+				ao_gps_data.second = nav_timeutc.sec;
+
+				ao_gps_data.pdop = nav_dop.pdop;
+				ao_gps_data.hdop = nav_dop.hdop;
+				ao_gps_data.vdop = nav_dop.vdop;
+
+				/* mode is not set */
+
+				ao_gps_data.ground_speed = nav_velned.g_speed;
+				ao_gps_data.climb_rate = -nav_velned.vel_d;
+				ao_gps_data.course = nav_velned.heading / 200000;
+				
+				ao_gps_tracking_data.channels = 0;
+
+				struct ao_telemetry_satellite_info *dst = &ao_gps_tracking_data.sats[0];
+
+				for (i = 0; i < nav_svinfo_nsat; i++) {
+					struct nav_svinfo_sat *src = &nav_svinfo_sat[i];
+
+					if (!(src->flags & (1 << NAV_SVINFO_SAT_FLAGS_UNHEALTHY)) &&
+					    src->quality >= NAV_SVINFO_SAT_QUALITY_ACQUIRED)
+					{
+						dst->svid = src->svid;
+						dst->c_n_1 = src->cno;
+						dst++;
+						ao_gps_tracking_data.channels++;
+					}
+				}
+
+				ao_mutex_put(&ao_gps_mutex);
+				ao_wakeup(&ao_gps_data);
+				ao_wakeup(&ao_gps_tracking_data);
+				break;
+			}
+			break;
+		}
+	}
+}
+
+__xdata struct ao_task ao_gps_task;
+
+void
+ao_gps_init(void)
+{
+	ao_add_task(&ao_gps_task, ao_gps, "gps");
+}
diff --git a/src/drivers/ao_gps_ublox.h b/src/drivers/ao_gps_ublox.h
new file mode 100644
index 00000000..13bf6955
--- /dev/null
+++ b/src/drivers/ao_gps_ublox.h
@@ -0,0 +1,241 @@
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#ifndef _AO_GPS_UBLOX_H_
+#define _AO_GPS_UBLOX_H_
+
+struct ublox_hdr {
+	uint8_t		class, message;
+	uint16_t	length;
+};
+
+#define UBLOX_NAV		0x01
+
+#define UBLOX_NAV_DOP		0x04
+
+struct ublox_nav_dop {
+	uint8_t		class;		/* 0x01 */
+	uint8_t		message;	/* 0x04 */
+	uint16_t	length;		/* 18 */
+
+	uint32_t	itow;		/* ms */
+	uint16_t	gdop;
+	uint16_t	ddop;
+	uint16_t	tdop;
+	uint16_t	vdop;
+	uint16_t	hdop;
+	uint16_t	ndop;
+	uint16_t	edop;
+};
+
+#define UBLOX_NAV_POSLLH	0x02
+
+struct ublox_nav_posllh {
+	uint8_t		class;		/* 0x01 */
+	uint8_t		message;	/* 0x02 */
+	uint16_t	length;		/* 28 */
+
+	uint32_t	itow;		/* ms */
+	int32_t		lat;		/* deg * 1e7 */
+	int32_t		lon;		/* deg * 1e7 */
+	int32_t		height;		/* mm */
+	int32_t		hmsl;		/* mm */
+	uint32_t	hacc;		/* mm */
+	uint32_t	vacc;		/* mm */
+};
+
+#define UBLOX_NAV_SOL		0x06
+
+struct ublox_nav_sol {
+	uint8_t		class;		/* 0x01 */
+	uint8_t		message;	/* 0x06 */
+	uint16_t	length;		/* 52 */
+
+	uint32_t	itow;		/* ms */
+	int32_t		ftow;		/* ns */
+	int16_t		week;
+	int8_t		gpsfix;
+	uint8_t		flags;
+	int32_t		exefx;		/* cm */
+	int32_t		exefy;		/* cm */
+	int32_t		exefz;		/* cm */
+	uint32_t	pacc;		/* cm */
+	int32_t		exefvx;		/* cm/s */
+	int32_t		exefvy;		/* cm/s */
+	int32_t		exefvz;		/* cm/s */
+	uint32_t	sacc;		/* cm/s */
+	uint16_t	pdop;		/* * 100 */
+	uint8_t		reserved1;
+	uint8_t		numsv;
+	uint32_t	reserved2;
+};
+
+#define UBLOX_NAV_SOL_GPSFIX_NO_FIX		0
+#define UBLOX_NAV_SOL_GPSFIX_DEAD_RECKONING	1
+#define UBLOX_NAV_SOL_GPSFIX_2D			2
+#define UBLOX_NAV_SOL_GPSFIX_3D			3
+#define UBLOX_NAV_SOL_GPSFIX_GPS_DEAD_RECKONING	4
+#define UBLOX_NAV_SOL_GPSFIX_TIME_ONLY		5
+
+#define UBLOX_NAV_SOL_FLAGS_GPSFIXOK		0
+#define UBLOX_NAV_SOL_FLAGS_DIFFSOLN		1
+#define UBLOX_NAV_SOL_FLAGS_WKNSET		2
+#define UBLOX_NAV_SOL_FLAGS_TOWSET		3
+
+#define UBLOX_NAV_STATUS	0x03
+
+struct ublox_nav_status {
+	uint8_t		class;		/* 0x01 */
+	uint8_t		message;	/* 0x03 */
+	uint16_t	length;		/* 16 */
+
+	uint8_t		gpsfix;
+	uint8_t		flags;
+	uint8_t		fixstat;
+	uint8_t		flags2;
+
+	uint32_t	ttff;		/* ms */
+	uint32_t	msss;		/* ms */
+};
+
+#define UBLOX_NAV_STATUS_GPSFIX_NO_FIX			0
+#define UBLOX_NAV_STATUS_GPSFIX_DEAD_RECKONING		1
+#define UBLOX_NAV_STATUS_GPSFIX_2D			2
+#define UBLOX_NAV_STATUS_GPSFIX_3D			3
+#define UBLOX_NAV_STATUS_GPSFIX_GPS_DEAD_RECKONING	4
+#define UBLOX_NAV_STATUS_GPSFIX_TIME_ONLY		5
+
+#define UBLOX_NAV_STATUS_FLAGS_GPSFIXOK			0
+#define UBLOX_NAV_STATUS_FLAGS_DIFFSOLN			1
+#define UBLOX_NAV_STATUS_FLAGS_WKNSET			2
+#define UBLOX_NAV_STATUS_FLAGS_TOWSET			3
+
+#define UBLOX_NAV_STATUS_FIXSTAT_DGPSISTAT		0
+#define UBLOX_NAV_STATUS_FIXSTAT_MAPMATCHING		6
+#define UBLOX_NAV_STATUS_FIXSTAT_MAPMATCHING_NONE		0
+#define UBLOX_NAV_STATUS_FIXSTAT_MAPMATCHING_VALID		1
+#define UBLOX_NAV_STATUS_FIXSTAT_MAPMATCHING_USED		2
+#define UBLOX_NAV_STATUS_FIXSTAT_MAPMATCHING_DR			3
+#define UBLOX_NAV_STATUS_FIXSTAT_MAPMATCHING_MASK		3
+
+#define UBLOX_NAV_STATUS_FLAGS2_PSMSTATE		0
+#define UBLOX_NAV_STATUS_FLAGS2_PSMSTATE_ACQUISITION			0
+#define UBLOX_NAV_STATUS_FLAGS2_PSMSTATE_TRACKING			1
+#define UBLOX_NAV_STATUS_FLAGS2_PSMSTATE_POWER_OPTIMIZED_TRACKING	2
+#define UBLOX_NAV_STATUS_FLAGS2_PSMSTATE_INACTIVE			3
+#define UBLOX_NAV_STATUS_FLAGS2_PSMSTATE_MASK				3
+
+#define UBLOX_NAV_SVINFO	0x30
+
+struct ublox_nav_svinfo {
+	uint8_t		class;		/* 0x01 */
+	uint8_t		message;	/* 0x30 */
+	uint16_t	length;		/* 8 + 12 * numch */
+
+	uint32_t	itow;		/* ms */
+
+	uint8_t		numch;
+	uint8_t		globalflags;
+	uint16_t	reserved;
+};
+
+#define UBLOX_NAV_SVINFO_GLOBAL_FLAGS_CHIPGEN	0
+#define UBLOX_NAV_SVINFO_GLOBAL_FLAGS_CHIPGEN_ANTARIS	0
+#define UBLOX_NAV_SVINFO_GLOBAL_FLAGS_CHIPGEN_U_BLOX_5	1
+#define UBLOX_NAV_SVINFO_GLOBAL_FLAGS_CHIPGEN_U_BLOX_6	2
+#define UBLOX_NAV_SVINFO_GLOBAL_FLAGS_CHIPGEN_MASK	7
+
+struct ublox_nav_svinfo_block {
+	uint8_t		chn;
+	uint8_t		svid;
+	uint8_t		flags;
+	uint8_t		quality;
+
+	uint8_t		cno;		/* dbHz */
+	int8_t		elev;		/* deg */
+	int16_t		azim;		/* deg */
+
+	int32_t		prres;		/* cm */
+};
+
+#define UBLOX_NAV_SVINFO_BLOCK_FLAGS_SVUSED	0
+#define UBLOX_NAV_SVINFO_BLOCK_FLAGS_DIFFCORR	1
+#define UBLOX_NAV_SVINFO_BLOCK_FLAGS_ORBITAVAIL	2
+#define UBLOX_NAV_SVINFO_BLOCK_FLAGS_ORBITEPH	3
+#define UBLOX_NAV_SVINFO_BLOCK_FLAGS_UNHEALTHY	4
+#define UBLOX_NAV_SVINFO_BLOCK_FLAGS_ORBITALM	5
+#define UBLOX_NAV_SVINFO_BLOCK_FLAGS_ORBITAOP	6
+#define UBLOX_NAV_SVINFO_BLOCK_FLAGS_SMOOTHED	7
+
+#define UBLOX_NAV_SVINFO_BLOCK_QUALITY_QUALITYIND	0
+#define UBLOX_NAV_SVINFO_BLOCK_QUALITY_QUALITYIND_IDLE			0
+#define UBLOX_NAV_SVINFO_BLOCK_QUALITY_QUALITYIND_SEARCHING		1
+#define UBLOX_NAV_SVINFO_BLOCK_QUALITY_QUALITYIND_ACQUIRED		2
+#define UBLOX_NAV_SVINFO_BLOCK_QUALITY_QUALITYIND_UNUSABLE		3
+#define UBLOX_NAV_SVINFO_BLOCK_QUALITY_QUALITYIND_CODE_LOCK		4
+#define UBLOX_NAV_SVINFO_BLOCK_QUALITY_QUALITYIND_CARRIER_LOCKED_5	5
+#define UBLOX_NAV_SVINFO_BLOCK_QUALITY_QUALITYIND_CARRIER_LOCKED_6	6
+#define UBLOX_NAV_SVINFO_BLOCK_QUALITY_QUALITYIND_CARRIER_LOCKED_7	7
+#define UBLOX_NAV_SVINFO_BLOCK_QUALITY_QUALITYIND_MASK			7
+
+#define UBLOX_NAV_TIMEUTC	0x21
+
+struct ublox_nav_timeutc {
+	uint8_t		class;		/* 0x01 */
+	uint8_t		message;	/* 0x21 */
+	uint16_t	length;		/* 20 */
+
+	uint32_t	itow;		/* ms */
+	uint32_t	tacc;		/* ns */
+	int32_t		nano;		/* ns */
+
+	uint16_t	year;
+	uint8_t		month;
+	uint8_t		day;
+
+	uint8_t		hour;
+	uint8_t		min;
+	uint8_t		sec;
+	uint8_t		valid;
+};
+
+#define UBLOX_NAV_TIMEUTC_VALID_VALIDTOW	0
+#define UBLOX_NAV_TIMEUTC_VALID_VALIDWKN	1
+#define UBLOX_NAV_TIMEUTC_VALID_VALIDUTC	2
+
+#define UBLOX_NAV_VELNED	0x12
+
+struct ublox_nav_velned {
+	uint8_t		class;		/* 0x01 */
+	uint8_t		message;	/* 0x12 */
+	uint16_t	length;		/* 36 */
+
+	uint32_t	itow;		/* ms */
+
+	int32_t		veln;		/* cm/s */
+	int32_t		vele;		/* cm/s */
+	int32_t		veld;		/* cm/s */
+
+	uint32_t	speed;		/* cm/s */
+	uint32_t	gspeed;		/* cm/s */
+
+	int32_t		heading;	/* deg */
+	uint32_t	sacc;		/* cm/s */
+	uint32_t	cacc;		/* deg */
+};
+
+#endif /* _AO_GPS_UBLOX_H_ */
diff --git a/src/test/Makefile b/src/test/Makefile
index d4d98e54..08aa8cd5 100644
--- a/src/test/Makefile
+++ b/src/test/Makefile
@@ -1,7 +1,7 @@
 vpath % ..:../core:../drivers:../util:../micropeak:../aes
 
 PROGS=ao_flight_test ao_flight_test_baro ao_flight_test_accel ao_flight_test_noisy_accel ao_flight_test_mm \
-	ao_gps_test ao_gps_test_skytraq ao_convert_test ao_convert_pa_test ao_fec_test \
+	ao_gps_test ao_gps_test_skytraq ao_gps_test_ublox ao_convert_test ao_convert_pa_test ao_fec_test \
 	ao_aprs_test ao_micropeak_test ao_fat_test ao_aes_test
 
 INCS=ao_kalman.h ao_ms5607.h ao_log.h ao_data.h altitude-pa.h altitude.h
@@ -38,6 +38,9 @@ ao_gps_test: ao_gps_test.c ao_gps_sirf.c ao_gps_print.c ao_host.h
 ao_gps_test_skytraq: ao_gps_test_skytraq.c ao_gps_skytraq.c ao_gps_print.c ao_host.h
 	cc $(CFLAGS) -o $@ $<
 
+ao_gps_test_ublox: ao_gps_test_ublox.c ao_gps_ublox.c ao_gps_print.c ao_host.h
+	cc $(CFLAGS) -o $@ $<
+
 ao_convert_test: ao_convert_test.c ao_convert.c altitude.h
 	cc $(CFLAGS) -o $@ $<
 
diff --git a/src/test/ao_gps_test_ublox.c b/src/test/ao_gps_test_ublox.c
new file mode 100644
index 00000000..80671735
--- /dev/null
+++ b/src/test/ao_gps_test_ublox.c
@@ -0,0 +1,409 @@
+/*
+ * Copyright © 2009 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#define AO_GPS_TEST
+#include "ao_host.h"
+#include <termios.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#define AO_GPS_NUM_SAT_MASK	(0xf << 0)
+#define AO_GPS_NUM_SAT_SHIFT	(0)
+
+#define AO_GPS_VALID		(1 << 4)
+#define AO_GPS_RUNNING		(1 << 5)
+#define AO_GPS_DATE_VALID	(1 << 6)
+#define AO_GPS_COURSE_VALID	(1 << 7)
+
+struct ao_telemetry_location {
+	uint8_t			year;
+	uint8_t			month;
+	uint8_t			day;
+	uint8_t			hour;
+	uint8_t			minute;
+	uint8_t			second;
+	uint8_t			flags;
+	int32_t			latitude;	/* degrees * 10⁷ */
+	int32_t			longitude;	/* degrees * 10⁷ */
+	int16_t			altitude;	/* m */
+	uint16_t		ground_speed;	/* cm/s */
+	uint8_t			course;		/* degrees / 2 */
+	uint8_t			pdop;		/* * 5 */
+	uint8_t			hdop;		/* * 5 */
+	uint8_t			vdop;		/* * 5 */
+	int16_t			climb_rate;	/* cm/s */
+	uint16_t		h_error;	/* m */
+	uint16_t		v_error;	/* m */
+};
+
+#define UBLOX_SAT_STATE_ACQUIRED		(1 << 0)
+#define UBLOX_SAT_STATE_CARRIER_PHASE_VALID	(1 << 1)
+#define UBLOX_SAT_BIT_SYNC_COMPLETE		(1 << 2)
+#define UBLOX_SAT_SUBFRAME_SYNC_COMPLETE	(1 << 3)
+#define UBLOX_SAT_CARRIER_PULLIN_COMPLETE	(1 << 4)
+#define UBLOX_SAT_CODE_LOCKED			(1 << 5)
+#define UBLOX_SAT_ACQUISITION_FAILED		(1 << 6)
+#define UBLOX_SAT_EPHEMERIS_AVAILABLE		(1 << 7)
+
+struct ao_telemetry_satellite_info {
+	uint8_t		svid;
+	uint8_t		c_n_1;
+};
+
+#define AO_TELEMETRY_SATELLITE_MAX_SAT	12
+
+struct ao_telemetry_satellite {
+	uint8_t					channels;
+	struct ao_telemetry_satellite_info	sats[AO_TELEMETRY_SATELLITE_MAX_SAT];
+};
+
+#define ao_gps_orig ao_telemetry_location
+#define ao_gps_tracking_orig ao_telemetry_satellite
+#define ao_gps_sat_orig ao_telemetry_satellite_info
+
+void
+ao_mutex_get(uint8_t *mutex)
+{
+}
+
+void
+ao_mutex_put(uint8_t *mutex)
+{
+}
+
+static int ao_gps_fd;
+static FILE *ao_gps_file;
+
+#if 0
+static void
+ao_dbg_char(char c)
+{
+	char	line[128];
+	line[0] = '\0';
+	if (c < ' ') {
+		if (c == '\n')
+			sprintf (line, "\n");
+		else
+			sprintf (line, "\\%02x", ((int) c) & 0xff);
+	} else {
+		sprintf (line, "%c", c);
+	}
+	write(1, line, strlen(line));
+}
+#endif
+
+#include <sys/time.h>
+
+int
+get_millis(void)
+{
+	struct timeval	tv;
+	gettimeofday(&tv, NULL);
+	return tv.tv_sec * 1000 + tv.tv_usec / 1000;
+}
+
+static uint8_t	in_message[4096];
+static int	in_len;
+static uint16_t	recv_len;
+
+static void check_ublox_message(char *which, uint8_t *msg);
+
+char
+ao_serial1_getchar(void)
+{
+	char	c;
+	uint8_t	uc;
+	int	i;
+
+	i = getc(ao_gps_file);
+	if (i == EOF) {
+		perror("getchar");
+		exit(1);
+	}
+	c = i;
+	uc = (uint8_t) c;
+	if (in_len || uc == 0xb5) {
+		in_message[in_len++] = c;
+		if (in_len == 6) {
+			recv_len = in_message[4] | (in_message[5] << 8);
+		} else if (in_len > 6 && in_len == recv_len + 8) {
+			check_ublox_message("recv", in_message + 2);
+			in_len = 0;
+		}
+		
+	}
+	return c;
+}
+
+#define MESSAGE_LEN	4096
+
+static uint8_t	message[MESSAGE_LEN];
+static int	message_len;
+static uint16_t	send_len;
+
+void
+ao_serial1_putchar(char c)
+{
+	int	i;
+	uint8_t	uc = (uint8_t) c;
+
+	if (message_len || uc == 0xb5) {
+		if (message_len < MESSAGE_LEN)
+			message[message_len++] = uc;
+		if (message_len == 6) {
+			send_len = message[4] | (message[5] << 8);
+		} else if (message_len > 6 && message_len == send_len + 8) {
+			check_ublox_message("send", message + 2);
+			message_len = 0;
+		}
+	}
+
+	for (;;) {
+		i = write(ao_gps_fd, &c, 1);
+		if (i == 1)
+			break;
+		if (i < 0 && (errno == EINTR || errno == EAGAIN))
+			continue;
+		perror("putchar");
+		exit(1);
+	}
+}
+
+#define AO_SERIAL_SPEED_4800	0
+#define AO_SERIAL_SPEED_9600	1
+#define AO_SERIAL_SPEED_57600	2
+#define AO_SERIAL_SPEED_115200	3
+
+static void
+ao_serial1_set_speed(uint8_t speed)
+{
+	int	fd = ao_gps_fd;
+	struct termios	termios;
+
+	printf ("\t\tset speed %d\n", speed);
+	tcdrain(fd);
+	tcgetattr(fd, &termios);
+	switch (speed) {
+	case AO_SERIAL_SPEED_4800:
+		cfsetspeed(&termios, B4800);
+		break;
+	case AO_SERIAL_SPEED_9600:
+		cfsetspeed(&termios, B9600);
+		break;
+	case AO_SERIAL_SPEED_57600:
+		cfsetspeed(&termios, B57600);
+		break;
+	case AO_SERIAL_SPEED_115200:
+		cfsetspeed(&termios, B115200);
+		break;
+	}
+	tcsetattr(fd, TCSAFLUSH, &termios);
+	tcflush(fd, TCIFLUSH);
+}
+
+#define ao_time() 0
+
+uint8_t	ao_task_minimize_latency;
+
+#define ao_usb_getchar()	0
+
+#include "ao_gps_print.c"
+#include "ao_gps_ublox.c"
+
+static void
+check_ublox_message(char *which, uint8_t *msg)
+{
+	uint8_t	class = msg[0];
+	uint8_t	id = msg[1];
+	uint16_t len = msg[2] | (msg[3] << 8);
+	uint16_t i;
+	struct ao_ublox_cksum	cksum_msg = { .a = msg[4 + len],
+					      .b = msg[4 + len + 1] };
+	struct ao_ublox_cksum	cksum= { 0, 0 };
+
+	for (i = 0; i < 4 + len; i++) {
+		add_cksum(&cksum, msg[i]);
+	}
+	if (cksum.a != cksum_msg.a || cksum.b != cksum_msg.b) {
+		printf ("\t%s: cksum mismatch %02x,%02x != %02x,%02x\n",
+			which,
+			cksum_msg.a & 0xff,
+			cksum_msg.b & 0xff,
+			cksum.a & 0xff,
+			cksum.b & 0xff);
+		return;
+	}
+	switch (class) {
+	case UBLOX_NAV:
+		switch (id) {
+		case UBLOX_NAV_DOP: ;
+			struct ublox_nav_dop	*nav_dop = (void *) msg;
+			printf ("\tnav-dop    iTOW %9u gDOP %5u dDOP %5u tDOP %5u vDOP %5u hDOP %5u nDOP %5u eDOP %5u\n",
+				nav_dop->itow,
+				nav_dop->gdop,
+				nav_dop->ddop,
+				nav_dop->tdop,
+				nav_dop->vdop,
+				nav_dop->hdop,
+				nav_dop->ndop,
+				nav_dop->edop);
+			return;
+		case UBLOX_NAV_POSLLH: ;
+			struct ublox_nav_posllh	*nav_posllh = (void *) msg;
+			printf ("\tnav-posllh iTOW %9u lon %12.7f lat %12.7f height %10.3f hMSL %10.3f hAcc %10.3f vAcc %10.3f\n",
+				nav_posllh->itow,
+				nav_posllh->lon / 1e7,
+				nav_posllh->lat / 1e7,
+				nav_posllh->height / 1e3,
+				nav_posllh->hmsl / 1e3,
+				nav_posllh->hacc / 1e3,
+				nav_posllh->vacc / 1e3);
+			return;
+		case UBLOX_NAV_SOL: ;
+			struct ublox_nav_sol	*nav_sol = (struct ublox_nav_sol *) msg;
+			printf ("\tnav-sol    iTOW %9u fTOW %9d week %5d gpsFix %2d flags %02x\n",
+				nav_sol->itow, nav_sol->ftow, nav_sol->week,
+				nav_sol->gpsfix, nav_sol->flags);
+			return;
+		case UBLOX_NAV_SVINFO: ;
+			struct ublox_nav_svinfo	*nav_svinfo = (struct ublox_nav_svinfo *) msg;
+			printf ("\tnav-svinfo iTOW %9u numCH %3d globalFlags %02x\n",
+				nav_svinfo->itow, nav_svinfo->numch, nav_svinfo->globalflags);
+			int i;
+			for (i = 0; i < nav_svinfo->numch; i++) {
+				struct ublox_nav_svinfo_block *nav_svinfo_block = (void *) (msg + 12 + 12 * i);
+				printf ("\t\tchn %3u svid %3u flags %02x quality %3u cno %3u elev %3d azim %6d prRes %9d\n",
+					nav_svinfo_block->chn,
+					nav_svinfo_block->svid,
+					nav_svinfo_block->flags,
+					nav_svinfo_block->quality,
+					nav_svinfo_block->cno,
+					nav_svinfo_block->elev,
+					nav_svinfo_block->azim,
+					nav_svinfo_block->prres);
+			}
+			return;
+		case UBLOX_NAV_VELNED: ;
+			struct ublox_nav_velned *nav_velned = (void *) msg;
+			printf ("\tnav-velned iTOW %9u velN %10.2f velE %10.2f velD %10.2f speed %10.2f gSpeed %10.2f heading %10.5f sAcc %10.2f cAcc %10.5f\n",
+				nav_velned->itow,
+				nav_velned->veln / 1e2,
+				nav_velned->vele / 1e2,
+				nav_velned->veld / 1e2,
+				nav_velned->speed / 1e2,
+				nav_velned->gspeed / 1e2,
+				nav_velned->heading / 1e5,
+				nav_velned->sacc / 1e5,
+				nav_velned->cacc / 1e6);
+			return;
+		case UBLOX_NAV_TIMEUTC:;
+			struct ublox_nav_timeutc *nav_timeutc = (void *) msg;
+			printf ("\tnav-timeutc iTOW %9u tAcc %5u nano %5d %4u-%2d-%2d %2d:%02d:%02d flags %02x\n",
+				nav_timeutc->itow,
+				nav_timeutc->tacc,
+				nav_timeutc->nano,
+				nav_timeutc->year,
+				nav_timeutc->month,
+				nav_timeutc->day,
+				nav_timeutc->hour,
+				nav_timeutc->min,
+				nav_timeutc->sec,
+				nav_timeutc->valid);
+			return;
+		}
+		break;
+	}
+#if 1
+	printf ("\t%s: class %02x id %02x len %d:", which, class & 0xff, id & 0xff, len & 0xffff);
+	for (i = 0; i < len; i++)
+		printf (" %02x", msg[4 + i]);
+	printf (" cksum %02x %02x", cksum_msg.a & 0xff, cksum_msg.b & 0xff);
+#endif
+	printf ("\n");
+}
+
+void
+ao_dump_state(void *wchan)
+{
+	if (wchan == &ao_gps_data)
+		ao_gps_print(&ao_gps_data);
+	else
+		ao_gps_tracking_print(&ao_gps_tracking_data);
+	putchar('\n');
+	return;
+}
+
+int
+ao_gps_open(const char *tty)
+{
+	struct termios	termios;
+	int fd;
+
+	fd = open (tty, O_RDWR);
+	if (fd < 0)
+		return -1;
+
+	tcgetattr(fd, &termios);
+	cfmakeraw(&termios);
+	cfsetspeed(&termios, B4800);
+	tcsetattr(fd, TCSAFLUSH, &termios);
+
+	tcdrain(fd);
+	tcflush(fd, TCIFLUSH);
+	return fd;
+}
+
+#include <getopt.h>
+
+static const struct option options[] = {
+	{ .name = "tty", .has_arg = 1, .val = 'T' },
+	{ 0, 0, 0, 0},
+};
+
+static void usage(char *program)
+{
+	fprintf(stderr, "usage: %s [--tty <tty-name>]\n", program);
+	exit(1);
+}
+
+int
+main (int argc, char **argv)
+{
+	char	*tty = "/dev/ttyUSB0";
+	int	c;
+
+	while ((c = getopt_long(argc, argv, "T:", options, NULL)) != -1) {
+		switch (c) {
+		case 'T':
+			tty = optarg;
+			break;
+		default:
+			usage(argv[0]);
+			break;
+		}
+	}
+	ao_gps_fd = ao_gps_open(tty);
+	if (ao_gps_fd < 0) {
+		perror (tty);
+		exit (1);
+	}
+	ao_gps_file = fdopen(ao_gps_fd, "r");
+	ao_gps();
+	return 0;
+}