We are developing a communications system for an UAV helicopter using mikrotik boards. The heli is equipped with a SR2 with two antennas, one located at the left side of the UAV an the other at the right side, so regardless of heli orientation, we have at least one antenna with clear line of sight.
We use a simple script that is monitoring signal strength, and when it’s not a value below zeor, we switch antennas.
Here is the code of the script that makes the switching…
:global radio "wlanSR2";
:global countdown 0;
:global signal;
:global ant;
:log warning "Connection Lost on $radio";
:set ant [/interface wireless get $radio antenna-mode];
:if (ant = "ant-a") do={
/interface wireless set $radio antenna-mode=ant-b;
}
:if (ant = "ant-b") do={
/interface wireless set $radio antenna-mode=ant-a;
}
:set countdown 10;
:set signal 0;
:while ((countdown != 0) && (! (signal<0))) do={
:delay 500ms;
/interface wireless monitor $radio once do={:set signal $"signal-strength";}
:set countdown ($countdown-1);
:log warning "Waiting connection on $radio. Countdown # $countdown . Signal:$signal";
}
}
It just changes the antenna-mode value, and if I run this script manually,antenna switch and reconnection is made in less than a second.
The problem is when I try to call this Script from the Monitor script… here’s the monitor script code.
Configure the AP as bridge, with WDS.
The heli antennas as wds too.
Try to connect both antennas to the AP.
The bridge mode only accepts 1 remote connection at the same moment. When the heli turns, the other WDS will connect to the AP, but only one at the same time.
@Restebabez : i plan to use WIFI for telemetry (and perhaps later video link) for an aircraft UAV.
I have found your discussion
I would be very interested in having details about your hardware setup on your helicopter and Ground station.
Do you use your WIFI link also for telemetry only or other like control or video link?
What were the antennas you used on your UAV and Ground station?
What range were you able to fly?
Are you using Linux and with board did you use ?
Also could you share with me your latest script ?
I hope both you will read my message and i will appreciate to discuss with you
You could cover all the air with some sector antenas putted in the ground, but I think it will be very difficult.
You need to try if you have connectivity at such speed with one antena and one client in the aircraft and how many KM you can reach, and later try to cover all the zone.
I think the problem is the type of antena in the client side.
Hello Martin,
Thanks for you reply.
I would like to establish a WIFI link between an UAV(aircraft or helicopter)
About the range i would like to try between 3 and 5 km.
This is what i was thinking about :
on the UAV, having a Bullet2 running Linux RouterOS with a 2,4 Ghz 9dB antenna.
I can have a Bullet 2 with up to 1 W power in Xmit
On the ground side, connected to a laptop running Linux, an Alpha WIFI to USB adapter (1W)
For the antenna i was planning to have a Patch antenna on a tracking system to follow the UAV.
What do you think about this setting?
Is there some kind of QoS in RouterOS if i want to add Video to telemetry link?
(of course i will start with telemetry which has a “small” bandwith)
What kind of latency range can i expect if you have an idea?
Could i benefit from using on the UAV two antenna’s and a script like described by restebanez?
Do you have any remarks our suggestions ?
I don’t have a free mini-PCI slot in my Laptop for the XR2 card
So i plan to have a bullet2 connected to my Laptop
Could you help me for the antenna choice
-for the airplane bullet2 (i will remove plastic case and heavy N connector and solder in a 90 degree RP-SMA connector to have a light weight)
-For the bullet2 on the ground connected to the laptop?
