Getting Started Guide: RTCM Base Station

Overview

This guide is intended for first time RTCM Base Station users and provides an overview of how to handle with the required software, connect to and configure the RTCM Base Station.

 

Content

    1. Powering RTCM Base Station
    2. Connecting the RTCM Base Station
    3. The ANavS® Wizard to configure the RTCM Base Station

 

Powering RTCM Base Station

The RTCM Base Station can be powered with standard 230V AC-Voltage plug. Please use the delivered (orange) cable with the appropriate connector for the power supply input as marked in figure 1.

 

Connecting the RTCM Base Station

FIgure 1 shows the standard connections for the typical RTCM Base Station setup:
* Please connect the GNSS antenna with the marked SMA connector to the RTCM Base Station. The GNSS antenna must stay outside with open-sky environment (see figure 2).
* Bring your RTCM Base Station to the internet. For this, please connect the station to a router. Further instructions and other connection possibilities are given in article Publishing RTCM-Data for MSRTK Modules

Fig. 1: RTCM Base Station connections

 

Recommendation: The GNSS antenna should be fixed mounted on position outside with best possible satellite visibility (see figure 2). A recommended place would be the roof of a high building or similar places. The correction data of the RTCM Base Station are highly accurate for rovers with a distance of up to 15 km. So it makes sense to fix the RTCM Base Station on a location where you can calibrate the position once a time and don’t change the position again.

Fig. 2: RTCM GNSS antenna placement guideline

 

The ANavS® Wizard to configure the RTCM Base Station

For a precise absolute/relative position solution and to define the credentials for your RTCM Base Station, you need a one-time calibration before using the RTCM Base Station. The configuration will be saved and starts always after booting. The ANavS® Wizard includes this functionality with the following steps. To do the calibration steps, please connect to the WiFi Access-Point “ANavS_RTCM_service” (Password: anavsrtk) of the RTCM Base Station.

Figure 3 shows Step 1 of the ANavS® Wizard for RTCM Base Station calibration:
Please select the option “CALIBRATE ANavS RTCM Base Station”.

Fig. 3: Select the desired Modus (1. Step)

 

Figure 4 shows Step 2 of the ANavS® Wizard for RTCM Base Station calibration:
Your Laptop/PC is streaming sensor data of the RTCM Base Station to recognize the correct baudrate of the used sensor-setup in the RTCM Base Station. Only when sensor-setup can be recognized of the ANavS® Wizard, the user is able to go to the next step. If not, please check your WiFi-connection to the RTCM Base Station. Should the WiFi-connection be ok but no green picture appears after one minute, please restart the RTCM Base Station (Power-OFF/Power-ON).

Fig. 4: ANavS RTCM Connection (2. Step)

 

Figure 5 shows Step 3 of the ANavS® Wizard for RTCM Base Station calibration:
The user has two options for calibrating the stationary position of the RTCM Base Station:
* NTRIP-Client Connection: Please use this option to calibrate your RTCM Base Station with centimeter-accurate position. To do this, you need an external RTCM input-stream from an appropriate correction-data service-provider with centimeter accuracy. Depending on your service-level, ANavS® can do this also for you. The advantage of this modus is a precise relative and absolute position estimation of your rover equipt with MSRTK Module and ANavS® sensor fusion.
NOTE: To stream the correction data from external provider, one need internet-access. But you are already connected with WLAN to the RTCM Base Station and the connection must continue for the calibration process. The solution for this connection problem is either the use of ethernet connection of your Laptop/PC or to use a 4G or Wi-Fi-dongle on your Laptop/PC to get internet-access.

* Filtered Least-Squares Position-Solution: This is the standard way to calibrate a rough position estimation for the RTCM Base Station. You can do this without the need of additional services. It has no influence on the accuracy of the relative position-solution between rover (MSRTK Module) and RTCM Base Station, but the absolute position includes an position-offset depending on the accuracy of the position of the RTCM Station.

Fig. 5: Select Modus for RTCM Base Station calibration (3. Step)

 

Figure 6 shows Step 4 of the ANavS® Wizard for RTCM Base Station calibration when using the previous option NTRIP-Client Connection. After starting the software, the ANavS® Wizard is streaming the GNSS sensor data from the ANavS® RTCM Base Station and per internet-connection correction-data from an external service-provider. With this data, the ANavS® Wizard is trying a so called RTK ambiguity fixing. Each successful fixed RTK baseline is listed in the Table of RTK-Solutions. Please let this calibration run a reasonable time, that means more than 30 minutes. After having some solutions, please select the most reliable one (Count defines recurrent RTK-Fixings). A recommendation is that the same RTK-fixing should repeated three times. With clicking on the most relibale RTK-solution in the table, an averaging-process is started. After reaching the lower-bound of deviation, the light shown in the ANavS Wizard switch from red to green. Now you can stop the process (red stop-button) and enter your credentials for your own RTCM-stream with the ANavS® RTCM Base Station (figure 7).

Fig. 6: Starting Calibration with RTK Ambiguity Fixing with external source of correction data

 

Fig. 7: Define credentials and port number for RTCM Base Station

 

Figure 8 shows Step 4 of the ANavS® Wizard for RTCM Base Station calibration when using the previous option Filtered Least-Squares Position-Solution. After starting the software, the ANavS® Wizard is streaming the GNSS sensor data and estimates a rough position solution with averaging. After reaching the lower-bounds for standard-deviation and averaged samples, the light switch from red to green. With green light you can stop the software and a input-box for defining your credentials appears (figure 7). Please submitt your credentials, make a note of it, and wait for the Success-Message. After this, your ANavS® RTCM Base Station is ready for use.

Fig. 8: Starting Calibration with Least-Squares Position Estimation

 

An Example of a defined RTCM-stream with default settings:
Username:                               RTCM_User
Password:                                anavs123
Port for RTCM-Service:           2101

This results in the following ntrip input stream for your MSRTK Board:
RTCM_User: anavs123@<IP-Address-of-ANavS-RTCM-Station>: 2101/ANAVS