Cool Pixhawk-compatible long-distance directional radio

Pharos matches a dynamic directional (beam shaping) radio on the air with another on the ground, with the two tracking each other for multi-mile range for video and telemetry. Coming to Kickstarter in 2-3 weeks. 

The Pharos is a newly-developed smart antenna. Unlike conventional omni-directional antennas that waste energy in all directions, the Pharos concentrates the available power where you need it most. Working in conjunction with the Pixhawk autopilot (a version with its own autopilot is being also developed), the antenna activates the side facing your UAV, boosting reception and range. A second Pharos can also be used on the aircraft, quadrocopter or UAV, keeping ground control in aim at all times.  The Pharos is also circular-polarized, granting immunity to polarization losses and multipathing signals, an optimum choice for challenging environments.

Air:

Ground:

Views: 4673


Moderator
Comment by Vladimir "Lazy" Khudyakov on May 5, 2016 at 3:51am

Interesting news.

Comment by JB on May 5, 2016 at 5:02am

EIRP?

Comment by Art on May 5, 2016 at 7:35am

The technical data is pretty limited, but based on what I see and data available, I don't think it is a "beam shaping 'radio'" As well as the statement on their web site: "high gain beam and keeps it always pointed to the drone control station" doesn't seem correct. It looks like an antenna diversity radio (just like RFD900+  The only difference is that they use 4 or 5 circular polarized patch antennas instead of 2 omnis.  It is interesting they don't advertise radiated power.  It would be interesting to know.   Another issue is that by switching from 900Mhz to 5.8Ghz at longer distances  you pretty much loose all the benefits of the higher gain antennas due to the free space path loss

Comment by Monroe King on May 5, 2016 at 5:54pm

IMO pretty much a gimmick I agree with Art +1 

It looks cool but... to me it's just a heavy (weight) diversity patch antenna.

Comment by MAGnet Systems on May 6, 2016 at 3:30pm

Chris,

Thank you for bringing the Pharos antenna to the blogs’s attention. We really hope this will be a useful product for the upcoming generations of drones.

 @Art, We thought that the web page we did to explain this new antenna concept of operations was simple enough in order not to confuse the user with too many technical details at this point. But most of the required specs are included there as this is a very straight forward system. If you need more information we’ll be glad to add them and you’ll find more on the upcoming kickstarter page that we plan to release by the end of the upcoming week.

First of all, a radio is not included into this antenna, so there is no point of mentioning EIRP (effective isotropically radiated power) on the specs. Users will plug their own 5.8GHz radios and then they will be able to calculate the EIRP for the radios they are using.

The Pharos antenna combines an antenna controller and 4 directional Xair antennas (10dBic each) as mentioned at the specs. Each antenna has a beam width of 90x90 degrees so the 4 of them cover all the 360 bearings around the antenna and +/- 45 degrees above/below the horizon.

The antenna controller works in parallel and gets information from the Pixhawk autopilot in order to continuously calculate the bearing from the drone to ground station (actually the Home Point) and activate the antenna that faces towards that direction each time.  

In the same principal, this antenna can be used on the ground station side and activate the antenna element that points to the drone.

This is graphically represented to the 2 animations we have included. You will see a couple of videos as well on the upcoming kickstarter page.

 

@ Monroe King, Personally, I wouldn’t use the term “diversity” antenna as the diversity antennas mostly refer to radio receivers but Pharos is used on both the receiver and the transmitter sides. The Pharos antenna is a tracking antenna system but with no moving parts. To that extend its 65 grams are several orders of magnitude less than comparable tracking antenna systems with moving parts i.e. servo motors. Not to mention that a tracking antenna system for the drone side does not currently exist but only for the ground station side (at least to my knowledge).

 

Evangelos 


Developer
Comment by Bill Bonney on May 6, 2016 at 7:25pm

Interesting. As always better at listening is more useful than shouting louder. Being able to to direct the sensitivity of the antenna array towards the transmitting station helps. This means higher bandwidth ground to drone connections, but as others have said, drone to ground is limited by the effective radiated power. This array could help with a lower power transmitter on the drone. But that's not really the bottleneck. transmitted power for the drone

On the ground it really could be an effective and small antenna tracker. that can be easily connected to a mobile GCS. I see that potentially more useful. 

Comment by Monroe King on May 6, 2016 at 7:36pm

Evangelos

Show me something that proves your antenna is better than a single CP?

You have not got my vote yet.

Diversity would work just as well if not better than using the flight controller to determine the GCS transceiver/receiver location.

A high gain directional antenna has a narrow beam that needs to point within at least 15 degrees in 2 planes to be effective.

Yes we need to see the radiation patterns and specifications of the antenna.

 

Comment by Hugo Chamberland on May 6, 2016 at 7:53pm

I am (TrueRC Canada) part the development of the Pharos antenna (not a radio but an antenna). It contain 4 especially modified x-air antennas and a very low loss switching circuit.  Switching is controlled by the autopilot (pixhawk) by way of IMU/GPS/MAG in the drone and/or as a GS. This make possible the scenario where the GS is moving in a vehicles or on a hand-held device. Switching is fast enough to be seamless and transparent to an analog video link or a digital modem. Having both air/ground antennas give a massive help not only by the gain, but the directivity and front/back ratio that reduce reflections on the drone itself and reduce the noise figure at the reception end.

-Hugo

Comment by Monroe King on May 6, 2016 at 7:58pm

Hugo

What is the gain and beamwith of the x-air antenna?

Comment by Hugo Chamberland on May 6, 2016 at 8:18pm

9.7dBic to be precise and 90deg on the horiz. axis, little less on the vert. as to make it so the beams overlap nicely

-Hugo

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