This document leads you through the efficient use of the u-center
evaluation software, the powerful and easy to use tool from u-blox for
evaluating, performance analysis and configuration of u-blox GNSS
positioning chips and modules.
u-blox reserves all rights to this document and the information contained herein. Products, names, logos and designs
described herein may in whole or in part be subject to intellectual property rights. Reproduction, use, modification or
disclosure to third parties of this document or any part thereof without the express permission of u-blox is strictly prohibited.
The information contained herein is provided "as is" and u-blox assumes no liability for the use of the information. No warranty,
either express or implied, is given with respect to, including but not limited to, the accuracy, correctness, reliability and fitness
for a particular purpose of the information. This document may be revised by u-blox at any time. For most recent documents,
please visit www.u blox.com.
1.2 Using this guide.......................................................................................................................................5
1.3.2 By email............................................................................................................................................ 5
1.3.3 Helpful information when contacting technical support....................................................... 5
3.4 Connect to the receiver......................................................................................................................... 8
3.4.1 Select the port................................................................................................................................ 8
3.4.2 Select the baud rate (only for COM ports)................................................................................9
4 Concept and philosophy................................................................................................... 10
4.1 Color and satellite coding scheme....................................................................................................11
4.2.3 Record mode................................................................................................................................. 13
4.2.4 Play mode.......................................................................................................................................13
4.2.5 Relations between modes..........................................................................................................13
5.2.3 Text console.................................................................................................................................. 29
5.2.4 Icons and text field of console views.......................................................................................30
u-center is u-blox's powerful GNSS evaluation and visualization tool which can be downloaded freeof-charge from our website (www.u-blox.com). This user guide provides a description of the features
of this software. It allows end users to assess and test u-blox GNSS positioning chips and modules
for navigation and positioning performance.
The purpose of u-center is to enable users to:
• Conduct performance tests on u-blox and other GNSS devices.
• Configure u-blox GNSS positioning chips and modules.
• Update the firmware on GNSS modules.
• Test the added performance provided by u-blox's AssistNow service.
1.2 Using this guide
This guide assumes that the user has basic computer skills and is familiar with the Windows
Graphical User Interface (GUI) and GNSS receiver environments.
The following symbols are used to highlight important information:
An index finger points out key information pertaining to integration and performance.
A warning symbol indicates actions that could negatively impact u-center behavior.
1.3 Technical support
If you have questions about installing or using u-center:
• Read this user guide carefully.
• Check our homepage (https://www.u-blox.com) to ensure that your GNSS device, firmware and
the u-center software are the latest versions.
• Refer to our web based information service.
1.3.1 Worldwide Web
Our website (www.u-blox.com) is a rich pool of information. Product information and technical
documents can be accessed 24/7.
1.3.2 By email
If you have technical problems or cannot find the required information in the provided documents,
contact the closest technical support office. To ensure that we process your request as soon as
possible, use our service pool email addresses rather than personal staff email addresses. Contact
details are at the end of the document.
1.3.3 Helpful information when contacting technical support
When contacting technical support, have the following information ready:
• Receiver type (e.g. NEO-7N), firmware version (e.g. 1.00), u-center release (e.g. u-center 8.00).
• Receiver configuration and short description of the application.
• Your complete contact details.
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u-center-User guide
2 Features
u-center evaluation software provides system integrators and end users with a quick and simple
way to interface with u-blox GNSS chipsets, modules and boards. It enables easy evaluation,
performance testing, development and debugging of GNSS positioning chips and modules. u-center
allows easy connection to u-blox products and provides a suite of features to view, log, and analyze
performance. The features include:
• Support for u-blox's receivers using u-blox positioning technology. u-center can communicate
with these receivers using either the UBX protocol or the NMEA-0183 standard protocol.
• Support for receivers that utilize standard NMEA strings.
• u-center presents all the information collected during the operation of the GNSS device. All
aspects of GNSS data (position, velocity, time, satellite tracking, etc.) can be monitored and
logged under various test scenarios for the evaluation of a receiver. u-center software allows
analysis of the collected data in order to investigate performance issues such as accuracy, road
test position and trajectory, satellite tracking, time to first fix, etc. All processed data can be
captured in ASCII format and ported into popular spreadsheets for creating additional plots
and statistics.
• Camera View: photographic data can be stored in the log file together with the navigation data
and later be replayed in the application.
• Export data files to Google Earth and Google Maps.
• Supports (Multiple GNSS) AssistNow Online and AssistNow Offline.
• Data recording and playback function.
• Structural and graphical data visualization in real-time.
• Export functionality to standard PC applications.
• Docking views (real-time cockpit instruments): Satellite constellation, compass, clock,
altimeter, speedometer, GNSS and satellite information views.
• Download firmware updates to GNSS positioning modules.
• Support for NTRIP server and NTRIP client functionality.
• Google Earth server support.
• SQLITE database support
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3 Getting started
3.1 General information about displayed values
• Longitude and latitude are displayed according to the datum selected in the GNSS device
(either the default WGS-84 or based on user-defined parameters). This option can be polled
and set using the UBX-CFG-DAT message.
• Time is displayed with reference to UTC.
• Elevation is displayed with reference to either MSL (Height above Mean Sea Level or
Orthometric Height) or to HAE (Height Above WGS-84-Ellipsoid). The reference is controlled by
the GNSS configuration.
3.2 Connecting an u-blox evaluation kit to the PC
This section assumes that you have purchased an u-blox evaluation kit. Should you try to connect a
module or IC receiver directly to the PC, make sure you use appropriate RS-232 level shifters.
The evaluation kit can be connected to the PC by using either an USB or a serial cable. In case of using
the USB port, a driver is required (installed by the u-center for Windows installer or downloadable
from our homepage). Be sure to install the driver before connecting the evaluation kit to the
computer.
3.3 Installing u-center
The installation program guides you through the necessary steps for a successful program
installation. During the installation, you can choose the destination folder for the program.
u-center uses dynamic link libraries (DLL). The installation program will automatically install
the required DLL's into the u-center program directory. Should you try to copy a u-center
installation from one location to another after the installation, make sure you copy the DLL
files as well.
After a successful installation, u-center can be started from the Start Menu (All Programs > u-blox
> u-center > u-center) and will start up as shown in Figure 1.
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Figure 1: Start display
3.4 Connect to the receiver
3.4.1 Select the port
Locate the communication toolbar (Figure 2) and click on the arrow beside the icon. This will show
a list with all available COM ports (Figure 3). Select the corresponding COM port where the receiver
is connected. If a link could be established, the icon will turn green and the text in the status bar
changes from to (in this example u-center is connected to COM6). This does
not mean that the communication already works but only that the port could be opened.
Figure 2: Communication Toolbar
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Figure 3: List of available COM ports
3.4.2 Select the baud rate (only for COM ports)
Again in the communication toolbar, click on the arrow beside the icon. This will show a
list with all available baud rates (Figure 4). Select the correct baud rate on which the receiver is
communicating (typically 9'600 baud). If u-center is able to decode data from the receiver, the status
bar begins to blink in green as shown in the following icon: . This means that the connection is
established successfully and the communication between the receiver and u-center is working.
Figure 4: List of available baud rates
Now you are ready to use the receiver.
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4 Concept and philosophy
Understanding the basic concept behind u-center is important in order to get the highest benefit out
of this powerful evaluation software. Figure 5 depicts the architecture of the software. The program
gets a data stream from either a communication port or a log file and splits this stream into protocol
messages. From the messages, relevant parameters are extracted and inserted into the current
dataset of the database that is used by the display and analysis features of the application.
In the current dataset, statistical values of the parameters are calculated. Average, minimum,
maximum and standard deviation are calculated for most parameters. If the available messages do
not provide a parameter, u-center tries to calculate the parameter from the ones that are available.
For example if velocity-north and velocity-east are available, u-center calculates the speed over
ground and course over ground, unless this data is already available in other messages.
Figure 5: Engine architecture
The u-center database size may be adjusted. If the size is exceeded u-center keeps only the latest
datasets and the oldest ones are removed. Refer to Database limitations for the details.
Very long recordings may decrease performance of u-center.
u-center provides various view classes (described below) for display and presentation. Most views
take their data from the database, but some get their data directly from the message without using
the database at all. The other views are updated when the database changes.
• Message Views display and decode a copy of every known message. These views allow observing
a single message in detail and they may also be used to configure the GNSS device. Refer to
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Messages view for details. The configuration view is a subset of the message view and only
displays message to configure the receiver.
• Console Views display the messages in text form. There is also a wide range of information
available which is useful for evaluation and testing. Refer to sections Packet console, Binary
console and Text console for details.
• Graphical Views display parameters from the database in graphical form. Charts (see Chart
view), histograms (see Histogram view) and a map view (see Map view) can be created. There are
two more views (deviation map and sky view, see Deviation map and Sky view) that may be used
for statistical performance and antenna pattern analysis.
• Tabular Views show the parameters of the database in tabular form. They can be freely
configured to allow customized tables. Refer to Table view and Statistic view for details.
• Docking Windows can be docked to the frame of u-center. An analog watch, compass, world
map, altitude and speed meter are available. There are also docking windows showing the current
signal power and the constellation of the satellites received by the device as well as a summary
of the GNSS status.
Displaying various views and docking windows requires computing power. Minimizing or
closing them may significantly reduce CPU usage.
4.1 Color and satellite coding scheme
In the graphical views and some docking windows, colors are used to indicate data quality. Table 1
shows the color codes for graphical views depending on the quality of the navigation solution.
ColorMeaning
Yellow
Orange
Green
Cyan
Magenta
Blue
Red
Table 1: Color-coding scheme for graphical views
Current value
Valid 3D navigation fix + Dead Reckoning
Valid 3D navigation fix
Valid 2D navigation fix
Dead Reckoning fix
Degraded navigation fix
No or invalid navigation fix
Table 2 gives the color-coding scheme for the docking windows and sky view. It indicates the state
of each satellite.
ColorMeaning
Green
Olive
Dark Green
Satellite used in navigation (with Ephemeris)
Satellite used in navigation (with Ephemeris and PPP)
Satellite used in navigation (with aiding data: AssistNow Autonomous, AssistNow Online/Offline)
Cyan
Blue
Red
Table 2: Color-coding scheme for the docking windows and sky view
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Satellite signal available, available for use in navigation
Satellite signal available, not available for use in navigation
Satellite signal not available
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Table 3 gives the satellite-coding scheme for the docking windows and sky view. It indicates to which
GNSS a satellite belongs.
CodeSystem
GxxGPS
RxxGLONASS
BxxBeiDou
ExxGalileo
SxxSBAS
QxxQZSS
Table 3: Satellite-coding scheme for the docking windows and sky view
Figure 6 shows the Status Color configuration. This is available under: Tools > Preferences > Status
Colors.
Figure 6: Color-coding configuration
4.2 Operating modes
u-center has different operating modes (see Figure 7). The mode changes when you open or close
a log file or when you invoke the player. To be able to use the record mode you have to create a new
file, save to a new file or open an existing file. The record and play mode are only available if you have
created a new file or when you have opened a writable file.
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Figure 7: Relation between operating modes
u-center-User guide
4.2.1 Online mode
In this mode a GNSS device is directly connected to u-center via a COM port. u-center can control
and configure the receiver and it will display the data that the receiver is sending periodically.
4.2.2 Stop mode
In this mode no data from a receiver or a log file is forwarded to the database and views. u-center is
in this mode when a log file is open but player and recorder are not active.
4.2.3 Record mode
Record Mode is the same mode as the Online Mode, except u-center additionally creates a log file,
concatenating all the messages sent by the receiver. You enter this mode by creating a new log file
or opening an existing log file without write protection and pressing the record button. An example
of using this mode would be to make overnight measurements and evaluate the data at a later time.
u-blox customer support may request a log file from you when you are experiencing a problem with
one of our receivers and will usually need this to be recorded with debug data enabled (see Receiver).
4.2.4 Play mode
The Play Mode allows replaying a previously recorded log file step by step, in real-time or at an
accelerated rate. You enter this mode by opening a file and pressing the play, step or scan button.
4.2.5 Relations between modes
The operating mode depends on the status of the log file player. Modes are changed by user actions.
Each mode has different states that are changed by a user action or by an event (see Figure 7). In
Online mode and Record mode, u-center displays data from the receiver. In Play mode data from a
log file is displayed. Play mode has different states:
• Play reads and displays messages periodically from the log file. The user interface is derived from
that of a CD player. u-center updates the views after each message.
• Step gets one message from the log file and immediately returns to paused Play state.
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• Scan reads messages periodically but the display is only updated when paused or by changing
the state.
Position can be set in a log file. This behaves differently in Play mode and Stop mode. In Stop mode
the position is just set and no data is read and displayed. u-center will start recording or playing from
that position when changing the mode. If position is set in Play mode, u-center will load the data up
to this position from the log file and display the contents.
4.2.6 Database limitations
The number of epochs displayed by views that show history (Table, Chart, Histogram, Sky, Satellite
level history etc.) can be limited in order to allow an efficient analysis of large log files and not to
consume too much disk space. There is a setting which controls this history database limit, which
is available under: Tools > Preferences > General. By default the value for the number of epochs is
set to 0, which means the database size is not limited. Any other number higher than 0 will limit the
size of this history database. When this limit is set, then the oldest values will be discarded after the
database reaches this limit size. Data stored to a log file is not affected by the database limitation.
Also controlled in Tools > Preferences > General is the max number of messages stored. This limit
applies to how many messages from a log file can be loaded and are playable. The default value for
this is set very high, but can be reduced to save disk space, or increased if a very large log file cannot
be fully loaded.
Figure 8: Example of setting maximum number of epochs to keep in database
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For long-term observations, it is recommended to record the messages to a log file.
If a high value of epochs is selected, the display of data in real-time cannot be guaranteed,
especially when graphical views are open.
4.2.7 Receiver information
u-center will try to retrieve some information about what kind of receiver is connected by sending
UBX-MON-VER message on every successful connection. In this way certain functionality can
automatically be disabled if it is not supported by the connected receiver. In some cases this might
not be the desired behavior as it might hinder some other operation where these extra messages
are not desired. There is a setting that controls if receiver information is auto-retrieved or not, and
that is available under: Tools > Preferences > General. By default the auto retrieval is enabled.
Figure 9: Enabling/disabling automatic receiver information retrieval
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5 u-center menus and windows
5.1 Main frame and toolbars
The main frame is the primary display screen of u-center. It displays all tool bars and some of the
information provided by the device. In the standard status bar, information about communication,
UTC time, connection time, used protocol (NMEA or UBX), used file, etc. is shown.
Button tool tip: A description about each button in the toolbars can be obtained by holding the
mouse cursor over the button for a few seconds. A tool tip message will appear near the icon with
additional information while a detailed description is displayed in the status display.
Figure 10: u-center main frame and toolbars
5.1.1 Standard menu bar
All u-center functions can be accessed through the standard menu bar. Commands can also be
accessed by shortcuts that are listed in the menus. Some often used operations are also available
in the different toolbars.
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5.1.1.1 File
Figure 11: File menu entries
u-center-User guide
FunctionDescriptionShortcut /
New...Creates a new log file. No data is yet written but only the file is opened. The
duration of the logging time is displayed in the status bar field Operating time.
Save...Creates a new log file, saves the data from the internal database to the log file and
starts immediately recording all new data from the receiver. This is useful when an
error or an unexpected event occurred and no log file was recorded. The size of the
ring buffer (4 MB) is large enough to retain the data for the last hour (approx.).
Open...Opens a stored log file to be replayed.Ctrl+O
CloseCloses the active file.
Database EmptyDeletes the internal database and all saved values.
Database ExportExports the internal database into HTML or KML data formats for displaying with
Google Map or Google Earth.
Google Map Html...Exports the internal database into HTML data format for displaying with Google
Map.
Google Earth Kml...Exports the internal database into KML data format for displaying with Google
Earth.
Google Earth Server...Starts u-center's Google Earth server which allows continuous and real time
tracking to be visualized in Google Earth.
Print...Prints the active document.
Print PreviewShows a preview of the print output.
Print Setup...Shows the setup dialog of the printer.
Recent FilesLists all recently used files.
Toolbar icon
Ctrl+N /
Ctrl+S /
Ctrl+E /
ExitExits u-center.Ctrl+F4
Table 4: File menu entries
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5.1.1.2 Edit
Figure 12: Edit menu entries
u-center-User guide
FunctionDescriptionShortcut /
CutCut the current selection and put in to the clipboard.Ctrl+X / Shift
CopyCopy the current selection to the clipboard.Ctrl+C / Ctrl-
PastePaste the clipboard content to the current position.Ctrl+V / Shift
DeleteDelete the current selection.Del
Select AllSelect all in the current view.Ctrl+A
Clear AllClear all in the current view.Ctrl+Del
Table 5: Edit menu entries
Toolbar icon
+Del /
Insert /
+Insert /
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5.1.1.3 View
u-center-User guide
Figure 13: View menu entries
FunctionDescriptionShortcut /
Packet ConsoleOpens the packet console.
Binary ConsoleOpens the binary console.
Text ConsoleOpens the text console.
Messages ViewOpens the dialog with all supported messages.
Configuration ViewOpens the dialog with all configuration messages. This is a subset of the
Generation 9
Configuration View
Statistic ViewOpens the statistic view with all data from the internal database.
Table ViewOpens the empty table view. All values from the internal database can be
Recent Table ViewLists all the table views that have been opened. This information comes from the
Map ViewOpens a window allowing to display a map.
Recent Map ViewLists all the maps views that have been opened. This information comes from the
Messages View.
Opens the dialog for Generation 9 Advance configuration view. All the Generation
9 receivers should be configured with this new dialog.
displayed individually.
Windows registry and is also valid after a restart of u-center.
Windows registry and is also valid after a restart of u-center.
Toolbar icon
F6 /
F7 /
F8 /
F9 /
Ctrl-F9 /
F10 /
F11 /
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FunctionDescriptionShortcut /
Chart ViewOpens a window with chart functionality. All values from the internal database can
be displayed individually.
Recent Chart ViewLists all the chart views that have been opened. This information comes from the
Windows registry and is also valid after a restart of u-center.
Histogram ViewOpens a window with histogram functionality. All values from the internal
database can be displayed individually.
Recent Histogram View Lists all the histogram views that have been opened. This information comes from
the Windows registry and is also valid after a restart of u-center.
Camera ViewOpens a window allowing to connect to a web cam and visualize and save the
image.
Deviation MapOpens a window with a position deviation map.
Sky ViewOpens a window with the sky view. The current position of the satellites and their
values from the internal database are shown.
Docking WindowsOpens a list with all available docking windows that can be shown.
Satellite PositionShows or hide the current satellite positions.
Satellite LevelShows or hide the current satellite levels.
Satellite Level HistoryShows or hide the history of the satellite levels.
World PositionShows or hide the current position on the world map.
DataShows or hide data from the navigation solution (like position, TTFF, accuracy and
DOPs).
Altitude MeterShows or hide the altitude meter.
Toolbar icon
F12 /
CompassShows or hide the compass.
Speed MeterShows or hide the speed meter.
WatchShows or hide the clock.
ToolbarsOpens a list with all available toolbars that can be shown.
Standard ToolbarShows or hide the standard toolbar.
Views ToolbarShows or hide the views toolbar.
Receiver ToolbarShows or hide the receiver toolbar.
Player ToolbarShows or hide the player toolbar.
Action ToolbarShows or hide the action toolbar.
Table 6: View menu entries
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5.1.1.4 Player
Figure 14: Player menu entries
u-center-User guide
FunctionDescriptionShortcut /
EjectCloses the active log file.
PausePauses reading or recording from the active log file.
RecordStarts recording to a new or already opened log file. Any data in the internal
database will not be written to the file. If you want to save this data into a log file,
open the File menu and click Save. To stop recording, press the same button.
StepbackSingle step function. The previous message is read.
StepSingle step function. The next message is read.Ctrl+Space /
PlayStarts reading from the active log file. The speed of the action can be chosen on
the sub-menu.
ScanReads the entire log file into the database and updates the display at the end of
the scan period.
Goto BeginSets the read position to the beginning of the log file.
Goto EndSets the read position to the end of the log file.
Table 7: Player menu entries
Toolbar icon
Ctrl+E /
Ctrl+P /
Ctrl+R /
Ctrl+B /
Ctrl+G /
Ctrl+F /
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5.1.1.5 Receiver
u-center-User guide
Figure 15: Receiver menu entries
FunctionDescriptionShortcut /
ConnectionDefines the port u-center connects to. The list is generated automatically using
the enumeration method under Tools > Preferences > Generic > Serial ports. The
currently used port will be indicated.
DisconnectDisconnects from a connected receiver.
COMxConnects to COMx with the current baud rate.
Network connectionConnects to a receiver through network.
Location APIConnects to the receiver using the Location API available in windows 7 onwards.
Sensor APIConnects to the receiver using the Sensor API in Windows 7 and Windows 8 (the
USB Sensor driver is required in this case) but not in Windows 10.
Baud rateDefines the baud rate of the communication. The list is predefined and cannot be
changed. The currently set baud rate will be indicated.
NTRIP Server/CasterEnables u-center to act as a NTRIP server.
NTRIP ClientEnables u-center to act as a NTRIP client.
AutobaudingEnables or disables autobauding for the current communication with the receiver.
Debug MessagesEnables all debug messages in the receiver. Can be requested from u-blox
support.
GenerationDefines the generation of the attached u-blox GNSS receiver. u-center also tries to
detect automatically the correct generation.
Protocol FilterSets the message filter against versions of protocol specification.
ActionLists all possible actions that can be performed with the u-blox GNSS receiver.
Toolbar icon
Ctrl+[1...9]
(if available)
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