C-Nav FAQ

C-Monitor® Application

I receive a Windows error when running C-Monitor after installation/upgrade.

After installing or upgrading C-Monitor, an error may appear when running the application: "The application failed to start because the application configuration is incorrect. Reinstalling the application may fix the problem." or "The application has failed to start because its side-by-side configuration is incorrect. Please see the application event log or use the command-line sxstrace.exe tool for more detail."

Solution: Download and install the Microsoft Visual C++ 2008 Redistributable Package from https://www.microsoft.com/en-us/download/details.aspx?id=29

What do I do if I receive an error stating “Warning: There is no authorized dongle connected. Please connect one immediately.”?

Ensure that the C-Nav dongle is securely connect to the computer’s USB port and the LED on the dongle (if applicable) is illuminated. You will also want to ensure that your dongle is license for C-Monitor by running the C-Nav Dongle Check. Lastly, the latest C-Nav Dongle Driver must be installed. The C-Nav Dongle Driver and C-Nav Dongle Check can be found in the Customer Support section of our website https://www.oceaneering.com/positioning-solutions/customer-access-and-resources

C-Nav Corrections Services

What is CCS Over-the-Air Almanac?

CCS OTA Almanac is a convenient way to update a C-Nav receiver's internal table of CCS correction satellites and frequencies. This is accomplished by transmitting the almanac over the CCS correction satellites at the top of each hour. Upon receipt of a new almanac with a constellation or frequency change, the receiver can automatically update its internal table to match the new changes. The operator can choose to automatically apply the update, wait for user intervention, or auto-switch at a user-defined time.

What is a SATDEFS file?

 A SATDEFS file is a small configuration file that defines the current C-Nav Corrections Satellite and SBAS constellations.  The file is used by C-Nav controller software and refreshes the list of available when applied.  It is especially useful for discontinued products, such as the C-Nav2000, C-Nav1010, and C-Nav2050 receivers, as it allows the operator to simply select a correction satellite from a list instead of manually tuning the receiver.  

How to upload a new SATDEFS file?

A SATDEFS file is typically only updated when there is a change to the C-Nav Corrections Service satellites, such as a constellation or frequency change.  Instructions to update the file can be found below.

C-Setup/C-Monitor/C-Scape

  • In the Main Window, select Update Corrections Satellite Configuration... from the Settings drop-down menu.
  • Press Browse then select the SATDEFS file that you wish to upload.
  • Press Update to load the new configuration.
  • The controller software will now use the updated file when selecting a C-Nav Correction Satellite in the Corrections Receiver page.

C-NaviGator II and III

  • Attached a USB drive (formatted as FAT) to the Windows PC.
  • Save the current SATDEFS configuration file to the top-level directory of the USB drive.
  • Ensure the computer has finished writing to the USB drive (use the Safely Remove Hardware tray icon if necessary) before removing the USB drive from the computer.
  • Access the Corrections Satellite Configuration page from Settings menu
    • C-NaviGator II: Press Scan USB to scan the USB drive for available configuration files. Tap to highlight the appropriate file and press Load File to load the new configuration.
    • C-NaviGator III: Press Load Configuration. Tap to highlight the USB drive and press Select Drive. Available Corrections Satellite Configuration Files will be listed. Tap to select the file then press Select File to load the new configuration.
  • Access the Corrections Receiver page to select a new corrections satellite.
To what datum is C-NavC1 corrections referenced?

C-NavC1 uses the latest realization of the International Terrestrial Reference Frame (ITRF). In other words, the C-NavC1 corrections are based upon ITRF14, and are adjusted on a daily basis (at UTC midnight) to account for minute shifts in velocity attributed to continental shifts on a global basis.

To what datum is C-NavC2 corrections referenced?

C-NavC2 uses the latest realization of the International Terrestrial Reference Frame (ITRF). In other words, the C-NavC2 corrections are based upon ITRF14, and are adjusted on a daily basis (at UTC midnight) to account for minute shifts in velocity attributed to continental shifts on a global basis.

How frequently do the C-Nav Corrections Service updates need to be received?

Unlike conventional Ground Based Augmentation Systems (GBAS) which determine highly temporal signal corrections, the C-Nav Corrections Service corrections are derived for satellite key parameters of orbit and clock. This is a more fundamental method of correction and as a result the accuracy degrades much more slowly with time. Excluding any sudden GNSS satellite anomalies, the last set of valid corrections will provide decimeter accuracies for up to and beyond 10 minutes. This is a setting made allowable to the user, which permits many accuracy tolerances dependent upon the application.

What is C-NavC2?

C-NavC2 includes GLONASS and a GPS (GNSS) clock, as well as orbit correctors. It provides a fully independent suite of clock and orbit correction algorithms, and fully independent servers in geographically separated processing centers. Features also include a second independent global network of C-Nav dual frequency GPS/GLONASS reference stations equipped with Sapphire based technology, and simultaneously broadcasts from two independent satellite networks (Net-1 and Net-2).

What is C-NavC1?

C-NavC1 is the World's first commercial Global Satellite Based Augmentation System (GSBAS). C-NavC1 uses a global tracking network of approximately 90 reference stations and software originally developed by NASA's Jet Propulsion Laboratory to calculate very precise and accurate real-time orbits and clocks for all the GPS satellites. These are transmitted via Geo-Stationary communication satellites to C-Nav receivers who use the corrections with C-Nav geodetic quality L1/L2 GPS engine measurements and proprietary C-Nav positioning algorithm. Real-time positioning accuracy is typically a decimeter horizontally and two decimeters vertically. Performance may be better depending upon the local conditions.

Will I be notified when a C-Nav Correction License is nearing expiration?

The C-Nav AuthCode System will automatically notify the original recipients of an AuthCode (C-Nav Correction License) that a license is nearing expiration. All email addresses associated with the original AuthCode, including all carbon copied (CC) recipients, will be notified.  

The following tables outline the interval at which a notification email is sent.

First Notification
>=daysNotify at days
18030
9014
307
31
Second Notification
>=daysNotify at days
18014
907

Examples:

  • A 280 day AuthCode will get a notification when 30 days remain and another when 14 days remain.
  • A 45 day AuthCode will get a single notification when 7 days remain.
  • A 3 day AuthCode will get a single notification when 1 day remain.

 

DISCLAIMER: Although C-Nav strives to notify AuthCode recipients in a timely manner, delivery of email messages cannot be guaranteed due to factors beyond our control.

How to manually tune a receiver to use an alternate C-Nav Corrections Satellite frequency?

This FAQ describes the steps to manually tune a C-Nav GPS/GNSS receiver to an alternate C-Nav Corrections Satellite frequency using C-Nav controller software and display units.

Important information for some versions of C-Nav controller software.

C-NaviGator III v7.0.7 and higher
C-NaviGator II v6.2.11 and higher
C-Monitor v7.1.0 and higher
C-Setup v7.1.0 and higher

Functionality has been added to update the list of available C-Nav Corrections Satellites via a small configuration file (SATDEFS). This allows the operator to simply select an appropriate C-Nav Corrections Satellite from a list rather than manually defining one. This is especially useful for discontinued products such as C-Nav2000, C-Nav1010, and C-Nav2050 receivers. Please refer to the FAQ How to load a SATDEFS file? for instructions

IDSatLonFreq MHzFreq MHzNet
4034F398W1,545.96751,545,967.51
5263F525E1,545.88501,545.885.01
6444F1143.51,545.97751,545,977.51
4473F454W1,545.97751,545,977.52
4853F315.5W1,545.98751,545,987.5 2
5654F164E1,545.96751,545,967.5 2
6794F3178E1,545.98751,545,987.52

C-Tides® Software Package

When I try to extract an Area of Interest, why do I get the error message "Can't find "TideAmp.mat" on path"?

This error occurs when the Area of Interest (AOI) is too large. Ideally, the AOI should be as small as possible around the desired location. Select a smaller bounding area and press Extract again.

When I try to extract an AOI, why do I get the error message “Can’t find ’XXXX.mat’ on path”?

There are three possible reasons for this error.

  1. The C-Tides Data package was not properly installed. Please read the section Install C-Tides Data(Page 12) of the C-Tides Quick Start Guide. Ensure that the C-Tides Data is installed into the same directory as the C-Tides® application.
  2. The Area of Interest is too large. Ideally, the AOI should be as small as possible around the desired location. Select a smaller bounding area.
  3. The MATLAB runtime has run out of system memory. Restart the C-Tides® application.
My computer made a ding sound while C-Tides was running, and now the application doesn’t seem to be doing anything.

The ding sound indicates that the MATLAB Runtime has triggered an unexpected error that caused the C-Tides® software to stop execution. It is best to close the application and send the error to C-Nav™ Support for further troubleshooting. To close the application, press Ctrl + C in the busy dialog window. This will allow you to then close the main C-Tides® application window.All errors are logged to a diagnostic log file. The most recent diagnostic log file can be found at:C:\Users\{USERNAME}\AppData\Local\C-Nav\C-Tides\

When I start the PVT1B input, why do I get the error message “PVT1B data timeout”?

This occurs when the C-Tides® Online application does not receive enough data to properly decode. Check the C-Nav3050® receiver output settings and ensure PVT1B is scheduled for at least 1Hz and that the baud rates match.

When I start the PVT1B input, why are there gaps in the output time?

This occurs when the C-Nav3050® receiver has more messages scheduled on the serial port than the PVT1B.  Check the C-Nav3050® receiver output settings and ensure that only PVT1B is scheduled for at least 1Hz.

Why is there no predicted data in my AOI?

The predicted tide values are derived from an independent solution that is detailed in the paper "FES 2004 Modern Insights". The values are based on a combination of MSS and tide gauge values around the world.

The predicted tide data are not available on land or in some areas near land. The easiest method to determine if the predicted tide data is available in your Area of Interest is to Plot Constituents. The last constituents graph—"ISLW: Approximately LAT w.r.t. MSL (m)"—will be non-white in areas with predicted tide data.

Why is the tidal height not the same as the predicted tide height?

The predicted tide is a 14-year average of model data. The tidal height is based off of real values which are open to influence by local conditions such as weather, GPS errors, or offset errors.

In certain areas there may be significant differences between the EGM and MSS model results. The MSS model should give a better correlation to the predicted tide beyond 10 km from shore. If both models are significantly different to the predicted tide, check the COG offsets.

Why is the tidal height not the same as the tide gauge in my area?

C-Tides is not a replacement for a tide gauge system. If the user is close enough to shore that tide gauges are available, then the user is too close to shore to be using C-Tides.

  • To use the MSS model, the vessel must be 10 kilometers from the nearest land mass.
  • To use the EGM model, the vessel must be in water with a depth of at least 10 meters. It is preferable to have a depth of at least 25 meters.

Using these models near-shore or in shallow water will affect the results due to land mass.

How do I get LAT from C-Tides?

Currently, C-Tides is not able to generate an LAT solution. We hope to be able to provide an update with LAT support soon.

C-Nav2050 Receiver

What Geoid Model is used in C-Nav2050 Receivers?

The legacy generation of C-Nav GPS products use a table of geoid-ellipsoid separation values to convert the computed GPS height (relative to the WGS84 ellipsoid) to height relative to mean sea level. The grid points of the table are spaced at two degrees of latitude and longitude. A four point interpolation is performed to predict the geoid-ellipsoid separation for the current navigation solution latitude and longitude. The table values are based on the geoidal model described in NIMA Technical Report 8350.2 which combines the Earth Gravitational Model 1996 (EGM96) with the WGS84 G873 datum. Because of the resolution of the grid table and statistical properties of the EGM96 model, there may be a few meters of error in the predicted geoid-ellipsoid separation value for a specific latitude and longitude. Typical errors are on the order of one meter.

C-Nav3050® Receiver

How do I get the C-Nav3050 WebUI?

The C-Nav3050 receiver must be running firmware version 3.3.x or later. A web server file is uploaded to the receiver using C-Setup, C-Monitor, C-NaviGator, or C-Scape. Please contact C-Nav Support for additional information.

What is a software upgradeable receiver?

Software upgradeability means that every C-Nav3050 already contains the hardware and software needed to support every possible combination of features. This makes the C-Nav3050 adaptable and customizable to meet changing application needs through software optioning alone. At purchase the receiver can be configured with any combination of options and later in order to meet the changing application needs, new options can be purchased and installed onsite without any hardware modification. What this means is any C-Nav3050 box can be upgraded from a basic GNSS Navigation receiver, to a RTK sensor.

Does the C-Nav3050 support RS-422 serial communication?

Yes, the C-Nav3050 DGNSS receiver’s COM2-USB interface port supports either RS232 or RS422 serial modes. The receiver’s default serial mode is RS232, but is switchable via the controller software.

What is Over-the-Air C-Nav licensing?

Over-the-Air (OTA) C-Nav Licensing is the easiest way to install a C-Nav Corrections license in a C-Nav3050 receiver. The installation of a purchased license is accomplished via radio broadcast. The C-Nav3050 receiver must be powered on and tracking a C-Nav Correction Satellite at the broadcast times.

C-Setup Installation

I receive a Windows error when running C-Monitor after installation/upgrade.

After installing or upgrading C-Monitor, an error may appear when running the application: "The application failed to start because the application configuration is incorrect. Reinstalling the application may fix the problem." or "The application has failed to start because its side-by-side configuration is incorrect. Please see the application event log or use the command-line sxstrace.exe tool for more detail."

Solution: Download and install the Microsoft Visual C++ 2008 Redistributable Package from https://www.microsoft.com/en-us/download/details.aspx?id=29

Miscellaneous

What are the C-Nav286 Phase Center Offsets?

Below, are the values of interest from the NGS site. The G01 values are the L1 values the G02 values are the L2 values.

CONVERTED FROM RELATIVE NGS ANTENNA CALIBRATIONS
G01
0.980.1383.15
G02
1.42-3.3983.35
What is P3QC and which C-Nav receivers support it?

In short, within every P3QC enabled C‐Nav receiver lies the ability to detect outliers, reject those that fall outside acceptable UKOOA and IMO confidence levels, and then report pertinent information about all accepted and rejected measurements, allowing the user to achieve an unprecedented level of positioning confidence.

C-Nav2050 receivers with firmware version 5.x.x and C-Nav3050 receivers support this technology.

What is Snapshot?

A Snapshot is a file containing the current state of C-Monitor, C-Setup, or C-NaviGator, including pertinent information about each connected device, to a standard HTML file that can easily be read. This file can also be sent to C-Nav Support for troubleshooting purposes.

 

To save a Snapshot...

 

C-NaviGator III

  • Insert a USB stick into an available USB port on the C-NaviGator.
  • Select Menu >> File >> Save/Load Settings.
  • At the bottom of the page, press the Save Snapshot button.
  • Tap to highlight/select the USB stick, then press the Select Drive button.
  • Wait several seconds for the file to be saved.
  • To retrieve the Snapshot, remove the USB stick from the C-NaviGator and insert it in a PC.
  • Navigate to the cnav/snapshot directory on the thumbdrive.
  • The file can be viewed in a web browser or emailed to C-Nav Support for troubleshooting purposes.

 

C-NaviGator II

  • Insert a USB stick into an available USB port on the C-NaviGator.
  • Select Menu >> File >> Take Snapshot.
  • Tap to highlight/select the USB stick, then press the Take Snapshot button.
  • To retrieve the Snapshot file, remove the USB stick from the C-NaviGator and insert it in a PC.
  • Navigate to the cnav/snapshot directory on the thumbdrive.
  • The file can be viewed in a web browser or emailed to C-Nav Support for troubleshooting purposes.

 

C-Monitor/C-Setup

  • In the Main Window, select File >> Save Snapshot.
  • Locate a convenient folder to save the file.
  • In the File name: text box, enter a descriptive name for the file.
  • Click the Save button.
  • The file can be viewed in a web browser or emailed to C-Nav Support for troubleshooting purposes.

 

What are Satellite-Base Augmentation Systems (SBAS)?

SBAS provide orbit and clock corrections for the GPS satellites and an Ionospheric model. These were initially developed for civil aviation use to augment L1 Coarse Acquisition Code receivers, but have since been developed for alternate markets such as offshore positioning and agriculture. Correctional data are transmitted on the GPS L1 frequency from Geo-stationary communication satellites. Examples include the Wide Area Augmentation System (WAAS) for USA and Puerto Rico, the European Geostationary Navigation Overlay Service (EGNOS) for Europe, the Multi-Function Satellite Augmentation System (MSAS) and the Satellite Navigation Augmentation System (SNAS) for China. Corrections can be received outside their network but should only be used within their designated operational area due to accuracy and reliability measures. All C-Nav receivers are capable of receiving and using SBAS signals.