NAVconfig User Guide

On the Home page there are 3 options to choose from. 

1. New Configuration: This options allows you to create a new configuration file that can be used to process data with in NAVsolve. It can be done without an INS device connected. 
2. Modify Configuration: This option allows you to take a configuration file that already exists and edit it. This can be used in post-processing if you made a mistake in configuring your device or to edit the configuration in real time with a device connected. More on this in the next section.
3. Improve Configuration: This option will tighten the uncertainties on values that you have entered for the physical setup using values that the INS has calculated during a warmup period. While the device is running it is constantly updating the values you have entered using the data coming in to make them more accurate. This option will save these values making it much quicker to achieve the highest performance when the device is next booted up in the same physical setup.
   
   After choosing this option you can choose which parameters are improved.
   

Hint: Selecting 'Modify configuration' is often the quickest way to alter the current configuration stored on a device to what you require.

Hint 2: Perform a short warm up after booting up the device by manoeuvring in various ways and then select 'Improve configuration' to save many of the calculations the INS does while working. 

If you choose a new configuration in the home tab you will see a 'Start Configuration page and if you choose modify configuration you will see a 'Read Configuration' page.

There are two sets of options here, where your file is coming from and what type of vehicle you are using. 

Start Configuration: Choose if you are connected to a device or not and select it from the drop-down if you are. Ensure your IP addresses are configured correctly for the software to pick up the device (ie make sure your ethernet connection is on the same IP range as the INS). Secondly, choose your vehicle type.

Read Configuration: Select where the file is being read from, whether it is a live device, a folder or if you want the config file that is stored within an RD file. Secondly, choose the type of vehicle you are using. 

Here is where you must input your measurements for the hardware setup of the INS in relation to the vehicle.

IMU orientation: Specify the orientation of the INS axes. This is easiest done using 90 degree rotations with respect to the vehicle axes however you can specify the angles exactly if you cannot do this. During operation, the INS will constatnly update the angles but you must ensure they are within 5 degrees of the true value (this tolerance can be altered). You can see physically on the device where the axes are facing or in the manual. 

You can then select the data rate you would like. 100Hz is the default.

Primary Antenna: Measure the relative 3D position along the vehicle axes of the antenna that is connected to the primary (left) antenna connector on the INS. 

Secondary Antenna: Measure the position of the secondary antenna relative to the primary antenna. This should ideally be displaced along a single axis. Try to make these antennas facing in the same direction (ie they are level within 15 degrees), if you cannot do this you can input an exact angle. 

Lateral No-slip: Lateral no-slip will improve the heading performance of the device and reduce position drift. Give the indicated measurements and also the type of surface being used.

Vertical No-slip: This will similarly improve your heading and drift performance. 

GNSS Differential Corrections: If you have an internal NTRIP client then you can enter the details in on this tab to get differential corrections in real time. If you are using a Base-station to achieve RTK position mode then this is where you set this option.

SBAS can be enabled on this page also.

LiDAR Scanner: This tab can quickly fill in some options that can be configured in later sections. Choosing the Velodyne VLP-16 LiDAR type will allow you to quickly configure sending NMEA messages over ethernet and serial depending on your setup and data logging.

You can input the IP address of the LiDAR device or choose a broadcast address of 255.255.255.255 to send data over ethernet to (the latter option may cause complications with network traffic). 

A Feature Code can be purchased to allow your xNAV650 device to log Ethernet traffic directly onto the unit. This allows you to bypass the need to monitor and record your files in real time. Files can be retrieved from the device in the same way as RD files via FTP interfacing.

You can log LiDAR data and telemetry  by choosing the correct ports and selecting the boxes. The default ports are used for the Velodyne LiDAR.  

When LiDAR data is logged in this way it is recorded as .lcom which is identical to a .pcap except without Ethernet headers. LCOM and PCAP files work identically in OxTS Georeferencer.

Please note that data logging does not work for all LiDAR. Data rates from LiDAR devices can be very large which can be overbearing for the CPU of the xNAV650. For Velodyne LiDAR usage, a 16 laser LiDAR will log comfortably onto the xNAV but a 32 laser LiDAR will not log correctly onto the xNAV.

Hint: For use with a LiDAR you can configure settings here and in the Interfaces page. You will need to send NMEA information over either serial or ethernet depending on your physical setup and you will need to send time synchronisation information. PPS can be sent over he digital I/O interface. Alternatively, PTP can be used to send time synchronisation information over ethernet.

In the Interfaces section you can configure the settings for a number of interface options on your device, including Ethernet and CAN Output and CAN Acquisition. It is also in this section where you set the IP address for a Driving Robot.

Ethernet: Ethernet data output can be enabled or disabled. You can choose NCOM or MCOM (specific for marine applications). The data rate can also be chosen between 1 and 100Hz.

The outputs for the triggers are configurable here also. If you configure your device to receive trigger messages you can output an NCOM message  on the falling or rising edge of the trigger or on the camera output trigger. 

Serial input: You can enable serial input commands on this tab. Selecting commands gives you a box with several options including the Baud rate, data bit length, the parity and the number of stop bits. Ensure these are compatible with the third party device you use. 

Serial 1 Output: There are various options for the serial output of the INS. You will have to choose the packet type, the Baud rate and the data rate.

If you choose NMEA packet type you must be more specific in which messages you require. You can also configure when they are output on triggers and at what periodic output they are output. 

Hint: If you are using multiple third party devices to receive NMEA messages on the same serial connection ensure that they are all compatible with the same Baud rate.

PPS/Triggers: PPS output can be configured to the falling or rising edge.

2 triggers can be configured to be received from other devices. The trigger type can be an input trigger, an output trigger or an IMU sync.

CAN output: CAN Output is disabled by default. Configure the navigation and status messages you want to output from your device and export a DBC file.

On the environment page you can choose initialisation settings, GNNS environment, vibration level, local coordinates and surface tilt.

Initialisation: For initialisation you can choose static or dynamic initialisation. If using a UAV, select static initialisation. If using a land vehicle, dynamic initialisation is ideal if you can begin moving in a straight line. Choose the target speed for initialisation also. 5m/s is the default. Choose also if you are initialising on level ground or not.

Local Coordinates: Enable or disable local coordinates. This will output trajectory measurements relative from a local origin that you can set here or in post-processing using NAVSolve. Local coordinates is necessary for Georeferencer. 

Measurement drift reduction: Several options are available to limit GNSS drift while stationary.

Surface tilt: Measurements for the tilt of the surface can be input on this tab.

GNSS environment: If you are testing in good open sky conditions with no or very little trees or buildings, then the default setting 'Open skies (no trees of buildings) is suffice. If you are driving in urban environments or expect frequent GNSS obstructions from trees, bridges etc. during data collection, then it is recommended to set the 'Frequent obstructions (many trees or buildings). In this case the device will trust the IMU sensor more than the GNSS receivers to calculate a reliable position.

Commands: Enter advanced commands into the box.

Accuracies: This tab allows you to alter the tolerances set on each measurement. These are tightened when you choose 'improve configuration' on the home page. The tighter you set these the quicker the device will be performing at its highest level but you must be certain of the uncertainty you can measure to. 

During operation, the INS will search the tolerances of all parameters and determine the values that best fit the incoming data. The purpose of a warmup is to tighten these tolerances. When you choose 'improve configuration' you are saving these values and you will notice that the accuracies tab will have changed. Default values are displayed here and these are recommended but you can alter them to suit your measurements particularly if you know some of them more confidently.

Hint: If you are consistently getting values after a warmup that you know are wrong, it might be that the original measurements were outside of the tolerance.

Slip points:

Displace output: This tab lets you output navigation data that is displaced from the true INS position. If you want the position of a camera or other device for example then you can use this.

GNSS Recovery: Various options allow you to tailor how the INS deals with unexpected GNSS measurements in both position and velocity. 

GNSS Control: Depending on the GNSS environment and the constellations you are using you can tailor the GNSS algorithm to best suit your application gx/ix is recommended especially for poor GNNS conditions.

Global Coordinate System: There are several different datums that are available to use. These use different models of the Earth to give navigation data in coordinate systems that are better suited to different geographic locations. Geoid altitude settings can also be configured here. 

Wheel Speed Input: To use a wheelspeed, enter the measurements required and calculate the pulses per metre. You will need to consult the datasheet of the wheelspeed device for this parameter. 

Acceleration filters: Acceleration Filters can be applied for angular and linear acceleration outputs.

Output Smoothing: This determines how fast the Kalman filter corrections are applied to the outputs from the device. When the Kalman filter determines that there is an error to correct, this error is applied smoothly rather than as a jump.  This option is particularly useful for autonomous vehicles or path-following robots as a rapid change in position can lead to a large change in the steering angle.

Now that you have entered your configuration settings you are ready to commit the settings to the device. This can be done via an Ethernet connetion from your PC, or over Wi-Fi if you are using the RT-XLAN Wi-Fi network.

Committing the configuration to a device will replace the config file stored on that device. 

You can choose to save the configuration or save and reset the INS. Choosing the former will mean that the new configuration will not take effect until the device is next restarted. 

If you wish to begin data collection immediately, reset the device and choose to automatically launch NAVdisplay with the warm-up template and NAVassist. THIS IS APPLICABLE TO AUTOMOTIVE TESTING CUSTOMERS ONLY.

This section displays information about the device that is connected to the application, including the feature codes that are enabled and the hardware and firmware device status.

 The Features Codes table shows the features that are enabled on your device

System Information shows: Product Information (product type), Hardware Configuration and Firmware Information.

This section contains global settings for the application, including Language, measurement units and the folder where configurations are saved to your PC.

Application settings include Language and Measurement unit type. You can also change where configuration files are saved on your PC.