Somat eDAQlite, Руководство пользователя

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I2773-4.
4
en 97
Somat eDAQ
lite
Notes on the Old GPS Module
The old GPS module has an antenna connection routed to the ELDIO front panel. This GPS module is a low-power
consumption 12-channel GPS receiver that is WAAS-enabled. Navigational updates are fixed at a rate of 1 Hz.
At highway driving speeds, this older GPS module does not always maintain sufficient communications lock on the GPS
satellites to consistently acquire GPS updates at a reasonable rate. This results in the GPS data going stale with invalid data
fills brought into play. This appears to happen more frequently at highway speeds, but has been observed in other test
scenarios. Furthermore, it can sometimes take a very long time for the GPS module to re-acquire satellite communications
lock (several minutes in some cases).
5.7.1 Available Inputs
GPS
Available GPS channels include latitude, longitude, altitude, speed (m/s, mph or
knots), heading, year, month, day, hour, minute, second, nanosecond, number of
satellites, fix quality and FAA mode. For more information on setting up GPS inputs,
see
“Bus-Oriented Input Channels” on page 121 .
NOTE
Position accuracy varies with several factors including, but not limited to, GPS receiver
configuration, location (geographic latitude, as it influences HDOP, and surrounding
objects possibly blocking reception or causing multi-path reception), satellite
constellation status and ionosphere conditions.
NOTE
There is an anomaly in the acquisition or processing of the GPS time that results in
some small discontinuities in the absolute GPS time data. This occurs when the “nsec”
channel rolls over and persists for about 20% of the time until the “nsec” channel rolls
over again (which takes about 4 hours). As such, there is at least one second of
uncertainty in the GPS time data stored in the data file whether or not the “nsec”
channel is stored.
5.7.2 Configuration Options
Hardware Interface
Select the desired GPS hardware interface.
Databases
Select one or more database files from the presented list. The selected databases
determine the channel types available when adding a GPS channel to the test setup.
5.8 EGPS-200 (Precision GPS Module)
The EGPS-200 module, part of the Somat Sensors product line, is a GPS receiver
designed for non-contact speed measurements in vehicle testing applications such as
braking and acceleration. The EGPS-200 module includes a 200 Hz combined speed
channel that combines three-axis acceleration and raw GPS speed readings for a
high-accuracy and fast updating output. The module includes an SMA connection for
HBM: public