Ground Station

General description of the ground station.

To access the user interface, the user needs to connect to the WiFi access point provided by the ground station. The network is called SkahaDrone, and the required password is printed on the ground station. A browser is required to connect to the network address on port 80. It is important to note that the user interface runs in HTTP, not HTTPS.

The ground station can be connected to a local area network (LAN) using its ethernet connector. By doing this, the user interface can be accessed at the IP address provided by the router. It should be noted that also here only http://xx.xx.xx.xx can be used, and not https://.

There are two indicator LEDs on the device. One is labelled Power and indicates that the internal processor is powered on. The other one is labelled Internet, which shows whether the ground station is connected to the Internet. However, this LED only confirms that the device is connected to the internet. It does not confirm whether the device is connected to the Skaha firmware or data server. This means that an ill-configured LAN firewall can block access to Skaha's server but still allow general internet traffic, which would result in the indicator LED being on.

Power Supply

The ground station requires a +5V power supply. It comes with a USB cable, but any power supply would work as long as the voltage does not exceed 5.3V and correct polarity is observed.

The ground station has an internal Li-Po battery installed to prevent data loss and avoid any sudden shutdowns or reboots in case of temporary power loss in the field. The battery gets charged when external power is supplied. If the external power source is disconnected, the ground station will shut down cleanly after a few minutes, and the LED indicator for power will turn off.

If the external power supply is disconnected for more than a few seconds and then reconnected, the shutdown process may have already begun. This could cause the internal processor to shut down, even if external power is still supplied. Although the Power indicator will still be on, giving the impression that the ground station is fully functional, the internal processor will not be running. To fix this issue, the user should reset the ground station using the reset button.

When external power is still supplied, the processor in the ground station may shut down under certain conditions. A reset may be necessary if the user interface becomes inaccessible or unresponsive.

Data Storage

The data is saved on the device in HDF5 file format and categorized into folders based on the creation date. Raw data is also saved in binary format in either the staging or archive folder. However, these raw data files are useless to the user as they are stored in an internal binary format. The user can access the folder containing the HDF5 files through the browser at port 8080.

Currently, file management is not available. Only downloads are possible. However, the ground station deletes the oldest files automatically when limited disk space is detected.

An hour of data collection typically produces 20 MB of data. The storage capacity is 5 GB, which can store over 250 hours of data.

The HDF5 files have identical information to the binary raw data files.

The entire disk can be wiped of any raw data and hdf5 files by pressing the "Erase All" button in the Internal tab. This will neither reset the ground station to a "factory" setting nor delete any other settings. It only removes data files in the staging, archive, and HDF5 folders.

Firmware Updates

When the ground station is connected to the Internet through its Ethernet connection, it establishes a connection with a server. This connection facilitates two things. Firstly, any firmware updates for the ground station and sensors are downloaded. Secondly, it permits Skaha to log in to the ground station and assist with debugging, sensor setup, or other related issues.

For the ground station to be able to connect to its firmware server, the following ports have to be allowed for outbound connections (and inward once the outward connection is established):

  • 443, 123, and 55

The following domains should be whitelisted:

  • *

  • *

The following DNS server is used if the local network provides no other:

  • Google's public DNS:

Data Upload

Data upload to Skaha's server and online data processing is optional and can be opted out of. Unless the data upload is deactivated, new raw data are stored in a staging folder on the ground station. After uploading to the server, files are moved into an archive. This happens in the background and should only be recognizable to the user through the staging and archive folder sizes shown in the Internal tab on the dashboard.

Data are uploaded to a server at the domain:

  • *

and port xxx has to be available for the MQTT protocol.

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