VRX Ground Unit Software Guide

Table of contents

1. VOXL SDK Support
   1. SDK Versions
2. Use Cases
   1. VTX to VRX Video Streaming over RF
      1. Using Multiple VRX to View Single VTX
      2. Viewing Multiple VTX from Single VRX
   2. VTX to VRX Video Streaming over IP
      1. Overview
      2. VRX Side Setup, with IP Over Ethernet
      3. VTX Side Setup, with IP Over LTE

VOXL SDK Support

SDK Versions

The VRX uses a different SDK than the drones at this time (5.4 kernel, Ubuntu20 rootfs):

Note: this version won’t work on drones yet.

Use Cases

VTX to VRX Video Streaming over RF

This is how systems are configured by default and use the integrated RF path to stream video.

Using Multiple VRX to View Single VTX

Multiple VRXs can view the stream from the same VTX (assuming they share encryption keys) and are on the same channel.

Viewing Multiple VTX from Single VRX

Again assuming the VTXs and VRXs share the same encryption keys, we can stream from multiple VTXs to a VRX (or again multiple VRXs…).

For this use case, we need to first configure the VTXs to be on different channels. The procedure is as follows:

Setup:

• Ensure VTXs/VRXs have same encryption key (or are all using the default)
• Power on one VTX at a time
• Change the frequency/channel of the VTX using the OSD menu (see this video at 223 seconds as to how to change frequencies/channels)
• Power off the VTX
• Set VRX back to default frequency/channel (5805/161)
• Power on next VTX to setup (assuming its out of the box, default frequency is 5805), and change frequency again off the default. Repeat for N VTXs.

Usage:

• All VTXs and VRX can be powered on now
• Using the Channel Scan buttons, you can scan through the available streams from the VTXs

VTX to VRX Video Streaming over IP

Overview

Another use case the VTX/VRX system supports is streaming over IP. Both drone and VRX are configured with VPN clients and can stream over through a network a VPN server facilitates. The pilot can view the low latency video via goggles connected to Display Port output.

NOTE: voxl-joystick-server is not shipping in SDK 1.4.5 and will ship in later release

VRX Side Setup, with IP Over Ethernet

The VRX is connected to the internet via a USB-to-ethernet adapter out of the utility USB port. In this case, the internal RF modem is not used at all.

To enable this use case, edit the /etc/modalai/voxl-vrx.conf file:

...
	"udp":	false,
	"udp_ip":	"",
	"udp_port":	-1,
...

For example, set udp_ip and udp_port to the IP/port address of the trasmitter/VTX/UAS

...
	"udp":	true,
	"udp_ip":	"100.ZZ.YY.XX",
	"udp_port":	50000,
...

VTX Side Setup, with IP Over LTE

On the “VTX” side (where in this case there is no M0185 VTX modem), we can use an IP based modem like the M0130 LTE modem/antennas/SIM card, e.g. similar to this.

To enable this use case, edit the /etc/modalai/voxl-vtx.conf file:

...
    "udp": false,
    "udp_transmitter_ip": "",
    "udp_transmitter_interface": "",
    "udp_receiver_configs": [
        {
            "ip": "",
            "port": -1
        }
    ],
...

For example, set udp_transmitter_ip and udp_transmitter_interface to the IP and interface name on the trasmitter/VTX/UAS side, and the reciever IP/ports that you want to send data to:

...
    "udp": false,
    "udp_transmitter_ip": "100.ZZ.YY.XX",
    "udp_transmitter_interface": "tailscale0",
    "udp_receiver_configs": [
        {
            "ip": "100.ZZ.YY.AA",
            "port": 50000
        }
    ],
...