The Data Logging pages are used to manage the logging of
GPS observation data to internal memory. These pages are
used to manage Sessions,
enable or disable the
AutoDelete and
Power Saving modes,
and view, download, or delete
logged data files.
The Status page provides the Session Status Table
if any sessions have been defined, provides the status of
AutoDelete Mode and
Power Saving Mode, and provides links to
edit these modes and create or edit sessions.
Sessions
A session is a process that logs data to one or more files. A new session is
created from the Status page by clicking on "Create a New Session". An existing
session may be modified by selecting the Session Name entry in the
Session Status Table or by selecting "Edit Sessions".
Any number of sessions may be defined, and multiple sessions may be active at
the same time. The following parameters are defined when creating or editing
a Session.
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Name/Enable - Each session has a name consisting of up to 10 characters.
This name appears in the session status table. Any enabled session will perform
data logging according to its schedule and other controls. Sessions are enabled
by default but may be disabled at the time of creation for future activation.
For example, a high rate session may be created, disabled, then be enabled at a
future date when high rate data is required.
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Schedule - Four session scheduling modes are available: Manual, Once Only,
Daily, and Continuous Logging. Additional controls are provided based on the
scheduling mode selected. The File or Session Duration is a common parameter
to all modes and is specified in minutes.
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Manual mode allows creation of a single file of a specified duration.
A Manual session may be re-enabled to create a new file at any time.
(Note that the File Duration range allows the creation of multi-day files
if desired, although this is appropriate in very limited situations.)
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A Once Only session has a start time specified to the minute.
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A Daily session will repeat every 24 hours.
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Continuous Logging creates consecutive data files with continuous phase
at a rollover interval specified by the File Duration. This is the most
common mode for a continuously operating reference station.
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Data Format - Currently, only T00 format files may be logged.
Options shown are appropriate for the type of data being logged.
The Measurement Rate defines the epoch interval for GPS code and carrier
phase logging. It may be set to "Off" when position only logging is desired.
The Position Rate specifies the interval for GPS position logging. It may
be set to "Off" if no positions are required. Check "Smooth Code Phase"
for carrier smoothed code observations. Check "Smooth Carrier Phase" to
log filtered carrier phase observations.
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File Naming - A Session Identifier is a single character that will
be appended to the names of files created by a session. A unique character
should be used for each session. By default, files are logged in a directory
structure organized by the year and month with a "YYYYMM" naming format.
Checking "Create Per-Day subdirectories" will log all data files for each
day in a single additional subdirectory. Checking the "Create Per-SessionId
subdirectories" will log all data files with the same Session Identifier
character in a single subdirectory under the date based directory,
either "YYYYMM" or "YYYYMM/DD".
EXTREMELY IMPORTANT - If any combination of sessions is defined where
more than one session may be started at the same time, make sure to use a
different Session Identifier character for each session.
(See File Naming in the list above.)
Note that there is no design imposed limit on the number of sessions that may
be created, but it is possible to exceed system performance limits by creating
a large number of high data rate sessions that are active at the same time.
A session may be deleted by editing the existing session and selecting the
"Delete" button at the bottom of the page.
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Session Status Table
The Session Status Table shows the current state of all sessions defined on the system.
This table shows the following parameters.
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Session Name - The name defined when the session was created.
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Schedule - Scheduling mode: Manual, Once Only, Daily, or Continuous.
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Duration - Session/File Duration in minutes.
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Status - If enabled, the status may be "Pending" if waiting for the
start time, active and indicated as "logging to " followed by the full directory
and file name of the file being logged, or "Completed". Otherwise, the status will
be indicated as "Disabled".
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Enable - Shows the status, which is "Enabled" if data logging is currently
active or scheduled for a future time, or "Disabled" if inactive. Clearing the
check in this control will immediately disable a session and terminate any currently
active logging. Entering a check in this control will activate a session for
immediate or future logging, depending on the scheduling mode.
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