Checking your GPS logger

This article is to assist you in checking that your RCLightSystems GPS Black Box is working correctly.

If you are using this as a requirement of the UK LMA Over 25Kg scheme you should check each year that your GPS logging mechanism is working and that you can access and read the data stored. Beyond that it is useful to check flights, you can see the maximum altitude and the path flown, all useful to understand the flights and ensure you are conforming to local rules or legal regulations. It can also be useful to refute any incorrect claims about a flight.

1 - Remove the card

You should make sure the unit is powered off before removing or inserting the SDCard. to remove, just press in slightly and it will pop out.

2 - Connect to your computer

The card is a micro SDCard, your computer might have a slot that accepts this style or card or you might have to use an adaptor (either converting it to a larger full SDCard size or a USB hub that accepts micro SDCards and connects to your computer).

3 - Find the files on the card

I'll assume Windows here, but it is similar for Macs. Open the file explorer and look for the SDCard as a drive. When you click on the drive you should see some folders with 6 digits. It will look something like this:

The 6 digits in the name represent the date, for example 250201 being the 1st Feb 2025 (01-02-25 but in reverse order). The GPS Black Box creates a folder for each day data is recorded.

Open the folder with the date you are interested in, for LMA annual certification pick the most recent folder.

Inside the date folder you will see files, one per power cycle of the GPS Black Box.

The files also have 6 digit names and these digits represent the time the flight started (specifically it's the timestamp that GPS data became available after power on). For example 164940 means 16:49:40 (so roughly ten to five in the afternoon). Note that the time is always in UTC so if the flight occurred during summer time then you need to add an hour to get the actual time.

4 - Viewing the flight data

Now that you can locate the flight files you can view the data. There are many online tools to view GPS NMEA data (that is what is stored in the files), we use one called GPSVisualizer.

Open this link https://www.gpsvisualizer.com/ and you will see the front page of the website.

Click on the 'Choose file' button and select your flight file from the SDCard

and click open. GPSVisualizer will generate a map with your flight overlaid.

This shows you the track flown, in the example above you can see it is hard to follow the flight. In the menu at the top left of the image (the three horizontal bars) you can click and select the option to 'Draw elevation profile'. This will place a graph at the bottom of the map the shows altitude during the flight. If you hover over the graph you will see a dot on the trace. As you move your mouse along the elevation profile the dot will move along the line on the map showing the flight path.

Once you have got to this point you can be sure your GPS logging is working and you will be compliant with the LMA regulations for Over 25Kg scheme.

Don't forget to put the SDCard back in the GPS Black Box!

5 - Advanced map display

This is a more advanced version of the map screen that allows you to display more information and change the map image size.

If you click on the 'Return to the GPSV map form' link to the right of the map you will see a more complex entry form. This form allows you to set the width and height of the map image, and 'Colorize by' for the track. Setting the width to 1024 and colorize by to Speed gives the following map:

Support / troubleshooting

If you have any questions please contact us and we will do our best to help. You can email to sales@rclightsystems.com or use messaging on our RCLightSystems Facebook page. We will respond as quickly as we can.