User manual
MPTP | MPTP commands 15
The precision of the position given in the Position field.
The unit for the precision is always meters. The range of the field is 0…255
meters . Values more than 254 are always indicated with 255 in the field.
The precision is estimation calculated from multiple variables.
Note that this field is present only if the Position format is 2 (WGS-84 with
precision) (cf. above)
In this example, the position precision has been 37 meters.
08.07.2003
_17:44:23
Time stamp
Date and time of the position given in the Position field. UTC (Universal
Coordinated Time, or Greenwich Mean Time) is always used, so the receiving
instrument needs to do a conversion to local time. A single field separator
character (_) separates date and time sub-fields.
In this example, the position has been acquired on July 8
th
, 2003, at 17:44:23.
The GPS receiver also provides the UTC time.
081km/h
Speed
Instrument’s speed at the time when the position was acquired.
The last four characters indicate the units used for speed, while the remaining
three are used for the numeric speed value. The possible numeric values are
0-999.
Currently, TWIG instruments do not support units other than kilometers per
hour (km/h), so the receiving instrument needs to do the conversion to other
units.
This field is omitted if the position source is net, as speed cannot be calculated
from GSM network measurement data.
In this example, the instrument has been moving at the speed of 81 kilometers
per hour.
114deg
Heading
Three digits and the string deg, indicating the compass direction of movement
of the instrument at the time when the position was acquired.
This field is omitted if the position source is net, as heading cannot be
calculated from GSM network measurement data.
In this example, instrument has been moving to the compass direction 114°,
i.e. approximately Southeast.
The single field which follows is again specific to the !TRG command. Having identified the
command as !TRG, the instrument which receives the message can interpret the field as
Data with value “81”. In this example, this value indicates that the speed of the instrument at
the time of the exceeding of the speed limit was 81 km/h.