OpenPlotter3 Headless For GPS & RTL-SDR AIS on RPi4 – Telecommunications, Navigation & Electronics

Introduction

Recently I was asked a question about AIS & OpenPlotter. I looked at various aspects of OpenPlotter2 several years ago (Ref.1/11) so I thought it would be a good idea to revisit the latest version3 of the Program. I downloaded RPi4_32bit images for Starter & Headless.

Starter Image Setup

Fig.4 OpenPlotter3 Application SDRVHF Menu

I first downloaded the RPi4_32bit starter image 22_07_18. I used Windows Disk Manager to delete the boot/linux partitions on a spare 32Gbyte SD card (cuidado-don’t wipe the wrong disk) and wrote the image using Raspberry Pi Imager. I then inserted the SD card and connected the RPi4 to a mouse/keyboard/HDMI_TV/Internet connection. The boot up process went smoothly and I was prompted to download/install updates (Fig.1). After this process I used the RPi Configuration to enable SSH/VNC/I2C in order to control the RPi over a LAN and use the various I2C sensors as I did before (Fig.2).

After this, I used the Settings Menu to install SDR VHF/GPIO/I2C Sensors/PyPilot (Fig.3). After this I opened SDRVHF and installed Gqrx (Fig.4). Finally I copied my charts into “Documents” and loaded them into OpenCPN.

Headless Image Setup

Fig.5 OpenCPN Serial Connection for Trimble GPS NMEA0183

I followed the same procedure for the Headless image as the Starter. The exception being that I only connected a LAN to the RPi4. I allowed a minute for bootup, then located the OpenPlotter on my Laptop WiFi networks. I connected using the default password “12345678”. Then I used VNC viewer to connect over the WiFi with address 10.10.10.1. Finally I logged into the RPi4 as “pi” “raspberry”. As before there was a prompt to download and install updates.

I installed the same applications as before with the Starter image. I loaded my Charts for OpenCPN. Then I plugged in my Trimble GPS and setup a serial connection for NMEA0183 in OpenCPN. A NMEA debug screen is available on OpenCPN to check if the GPS is sending data (Fig.6). Finally I checked Marine weather on Gqrx at 162.4MHz. There are a series of preset marine frequencies already programmed into Gqrx which is very handy. Finally I headed down to Lake Ontario to receive some AIS signals.

Headless Operation

Fig.12 OpenCPN Showing GPS Location (Red Boat) & AIS Contacts

Setup in the field (Fig.9) was straightforward, I used a lithium battery to power the RPi4, GPS and RTL-SDR. In order to see AIS traffic, you have to go into SDR VHF, highlight the AIS, select “Processes” and activate it. Then check on SignalK to see activity. At this point you can see the GPS location and AIS traffic on OpenCPN. In OpenCPN there should be two connections, one Serial for the GPS and one Network for Signal K (TCP/Port 3000). You can also connect the GPS data into SignalK and only have one connection into OpenCPN as an option.

Fig.13 YouTube Video OpenPlotter3 Headless on RPi4

Please send your comments, questions and suggestions to:
jclark@clarktelecommunications.com

References

Introduction

Starter Image Setup

Headless Image Setup

Headless Operation

References

By Jeremy Clark