|
@@ -0,0 +1,257 @@
|
|
|
|
+.TH GPSFS 8
|
|
|
|
+.SH NAME
|
|
|
|
+gpsfs, gpsevermore \- GPS time and position service
|
|
|
|
+.SH SYNOPSIS
|
|
|
|
+.B aux/gpsfs
|
|
|
|
+[
|
|
|
|
+.B -d
|
|
|
|
+.I device
|
|
|
|
+]
|
|
|
|
+[
|
|
|
|
+.B -b
|
|
|
|
+.I baud
|
|
|
|
+]
|
|
|
|
+[
|
|
|
|
+.B -s
|
|
|
|
+.I srvname
|
|
|
|
+]
|
|
|
|
+[
|
|
|
|
+.B -m
|
|
|
|
+.I mntpt
|
|
|
|
+]
|
|
|
|
+.PP
|
|
|
|
+.B aux/gpsevermore
|
|
|
|
+[
|
|
|
|
+.B -d
|
|
|
|
+.I device
|
|
|
|
+]
|
|
|
|
+[
|
|
|
|
+.B -b
|
|
|
|
+.I baud
|
|
|
|
+]
|
|
|
|
+[
|
|
|
|
+.B -n
|
|
|
|
+.I baud
|
|
|
|
+]
|
|
|
|
+[
|
|
|
|
+.B -l
|
|
|
|
+.I location
|
|
|
|
+]
|
|
|
|
+.SH DESCRIPTION
|
|
|
|
+.B Aux/gpsfs
|
|
|
|
+reads an NMEA-compatible serial GPS device and provides time and position
|
|
|
|
+through a file system, typically in
|
|
|
|
+.BR /mnt/gps .
|
|
|
|
+.PP
|
|
|
|
+It implements four files in the
|
|
|
|
+.B gps
|
|
|
|
+directory:
|
|
|
|
+.BR position ,
|
|
|
|
+.BR time ,
|
|
|
|
+.BR satellites ,
|
|
|
|
+and
|
|
|
|
+.BR raw .
|
|
|
|
+.PP
|
|
|
|
+The read-only
|
|
|
|
+.B position
|
|
|
|
+file contains one line of information in 9 tab-separated fields:
|
|
|
|
+.TP
|
|
|
|
+.I "fix quality
|
|
|
|
+0 means position data invalid, 1 means a 2D position is available, 2 means a 3D position is available.
|
|
|
|
+The value is 8, 9, or 10, respectively, when the fix data comes from a file rather than an actual GPS.
|
|
|
|
+.TP
|
|
|
|
+.I "zulu time
|
|
|
|
+universal coordinated time encoded as hhmmss followed by the character 'Z'.
|
|
|
|
+.TP
|
|
|
|
+.I "system time
|
|
|
|
+time and date converted to the format of
|
|
|
|
+.IR time (2).
|
|
|
|
+.TP
|
|
|
|
+.I longitude
|
|
|
|
+in degrees, east of Greenwich is positive, west negative.
|
|
|
|
+.TP
|
|
|
|
+.I latitude
|
|
|
|
+in degrees, positive is north, negative south of the equator.
|
|
|
|
+.TP
|
|
|
|
+.I altitude
|
|
|
|
+above sea level, in meters.
|
|
|
|
+.TP
|
|
|
|
+.I course
|
|
|
|
+degrees, clockwise from true north.
|
|
|
|
+.TP
|
|
|
|
+.I "ground speed
|
|
|
|
+in km/h
|
|
|
|
+.TP
|
|
|
|
+.I "magnetic deviation
|
|
|
|
+(not provided by all GPSs), in degrees, positive is westerly, negative easterly.
|
|
|
|
+.PP
|
|
|
|
+The read-only
|
|
|
|
+.B time
|
|
|
|
+file contains one line of information in 4 tab-separated fields:
|
|
|
|
+.TP
|
|
|
|
+.I "gps time
|
|
|
|
+in
|
|
|
|
+.IR time (2)
|
|
|
|
+format.
|
|
|
|
+.TP
|
|
|
|
+.I "gps time
|
|
|
|
+in
|
|
|
|
+.IR nsec (2)
|
|
|
|
+format (ms accuracy).
|
|
|
|
+.TP
|
|
|
|
+.I "system time
|
|
|
|
+in
|
|
|
|
+.IR nsec (2)
|
|
|
|
+format. This is the system time at the time of the
|
|
|
|
+.I "gps time
|
|
|
|
+sample. The difference between this and the previous field is used in clock
|
|
|
|
+synchronization. See
|
|
|
|
+.IR timesync (8).
|
|
|
|
+.TP
|
|
|
|
+.I validity
|
|
|
|
+the character
|
|
|
|
+.B A
|
|
|
|
+meaning sample valid and usable for clock synchronization. The other values are
|
|
|
|
+not usable for clock sync:
|
|
|
|
+.B B
|
|
|
|
+means valid sample from file playback,
|
|
|
|
+.B V
|
|
|
|
+means invalid sample, and
|
|
|
|
+.B W
|
|
|
|
+means invalid playback sample.
|
|
|
|
+.PP
|
|
|
|
+The read-only
|
|
|
|
+.B satellites
|
|
|
|
+file contains information about the current satellite constellation. It consists
|
|
|
|
+of one line of general information, followed by zero or more lines, one for each satellite in use.
|
|
|
|
+The first line contains two fields:
|
|
|
|
+.TP
|
|
|
|
+.I "fix quality
|
|
|
|
+same as in the
|
|
|
|
+.B position
|
|
|
|
+file.
|
|
|
|
+.TP
|
|
|
|
+.I "satellites in view
|
|
|
|
+number of satellites above the horizon
|
|
|
|
+.PP
|
|
|
|
+Subsequent lines have four fields:
|
|
|
|
+.TP
|
|
|
|
+.I prn
|
|
|
|
+satellite ID
|
|
|
|
+.TP
|
|
|
|
+.I elevation
|
|
|
|
+above the horizon, degrees.
|
|
|
|
+.TP
|
|
|
|
+.I azimuth
|
|
|
|
+direction, degrees from true north
|
|
|
|
+.TP
|
|
|
|
+.I snr
|
|
|
|
+Signal to noise ratio, 0 - 99 dB
|
|
|
|
+.PP
|
|
|
|
+The contents of these files are refreshed once per second when reading from an actual GPS,
|
|
|
|
+and once per 100 ms (giving a speed up of a factor 10) when playing back from file.
|
|
|
|
+.PP
|
|
|
|
+The read-only
|
|
|
|
+.B raw
|
|
|
|
+file can be read to obtain a copy of the raw NMEA GPS output.
|
|
|
|
+.I Gpsfs
|
|
|
|
+keeps an internal buffer of 8KB, so the reader must keep up with the output
|
|
|
|
+(typically 500 or so bytes per second).
|
|
|
|
+.PP
|
|
|
|
+The
|
|
|
|
+.B \-d
|
|
|
|
+flag establishes the device the GPS samples are read from. If the device file is not
|
|
|
|
+a serial interface,
|
|
|
|
+.I gpsfs
|
|
|
|
+assumes playback from file and modifies quality parameters as such.
|
|
|
|
+.PP
|
|
|
|
+The
|
|
|
|
+.B \-b
|
|
|
|
+flag specifies the baud rate of the serial line. The standard baud rate for NMEA
|
|
|
|
+GPS is 4800 baud, but many device allow changing to higher speeds.
|
|
|
|
+.PP
|
|
|
|
+The
|
|
|
|
+.B \-s
|
|
|
|
+flag specifies the name under which the
|
|
|
|
+.I gpsfs
|
|
|
|
+service is posted in
|
|
|
|
+.BR /srv .
|
|
|
|
+.PP
|
|
|
|
+The
|
|
|
|
+.B \-m
|
|
|
|
+flag specifies a mount mount other than
|
|
|
|
+.BR /mnt .
|
|
|
|
+.PP
|
|
|
|
+.B Aux/gpsevermore
|
|
|
|
+is used to configure GPSs using an Evermore chipset.
|
|
|
|
+.PP
|
|
|
|
+The
|
|
|
|
+.B \-d
|
|
|
|
+flag specifies the serial device to the GPS.
|
|
|
|
+.PP
|
|
|
|
+The
|
|
|
|
+.B \-b
|
|
|
|
+flag specifies the baud rate of the serial line. The standard baud rate for NMEA
|
|
|
|
+GPS is 4800 baud, but many device allow changing to higher speeds.
|
|
|
|
+.PP
|
|
|
|
+The
|
|
|
|
+.B \-n
|
|
|
|
+flag specifies the speed to set the GPS to. When the command finishes, the
|
|
|
|
+GPS should be read (and configured) at the new speed.
|
|
|
|
+.PP
|
|
|
|
+The
|
|
|
|
+.B \-l
|
|
|
|
+flag is sued to specify the location to initialize the GPS to. The format is
|
|
|
|
+.B dd:mm:ssX
|
|
|
|
+or
|
|
|
|
+.B dd:mm.mmmX
|
|
|
|
+or
|
|
|
|
+.BR dd.dddX ,
|
|
|
|
+where
|
|
|
|
+.B dd
|
|
|
|
+stands for degrees (one or more digits),
|
|
|
|
+.B mm
|
|
|
|
+for minutes and
|
|
|
|
+.B ss
|
|
|
|
+for seconds of arc.
|
|
|
|
+.B X
|
|
|
|
+is one of
|
|
|
|
+.BR W ,
|
|
|
|
+.BR E ,
|
|
|
|
+.B N
|
|
|
|
+or
|
|
|
|
+.BR S .
|
|
|
|
+Longitudes come with
|
|
|
|
+.B W
|
|
|
|
+or
|
|
|
|
+.BR E ,
|
|
|
|
+latitudes with
|
|
|
|
+.B N
|
|
|
|
+or
|
|
|
|
+.BR S .
|
|
|
|
+The
|
|
|
|
+.B \-l
|
|
|
|
+flag is followed by two such fields, one for longitude, one for latitude. They may be
|
|
|
|
+given in a single argument (separated by white space), or in two arguments, in either order.
|
|
|
|
+Initialization time is taken from
|
|
|
|
+.IR time (2).
|
|
|
|
+.SH "SEE ALSO
|
|
|
|
+.IR timesync (2),
|
|
|
|
+.IR time (2),
|
|
|
|
+.IR nsec (2).
|
|
|
|
+.SH FILES
|
|
|
|
+.TF /mnt/gps/satellites
|
|
|
|
+.TP
|
|
|
|
+.B /mnt/gps/position
|
|
|
|
+position, time, speed and heading
|
|
|
|
+.TP
|
|
|
|
+.B /mnt/gps/satellites
|
|
|
|
+satellites in view
|
|
|
|
+.TP
|
|
|
|
+.B /mnt/gps/time
|
|
|
|
+GPS time (millisecond accuracy)
|
|
|
|
+.TP
|
|
|
|
+.B /dev/eia0
|
|
|
|
+default GPS device
|
|
|
|
+.SH SOURCE
|
|
|
|
+.B /sys/src/cmd/aux/gps
|