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.
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Ground:
Comments
Looks interesting. I have been waiting for a phased array antenna but this doesnt look to be it.
There are some switching losses I presume?
Did you consider a single antenna on a gimbal?
What are the dimensions?
@Spencer Yes, this is how the Pharos antenna works. Everything is based on code running on the Pixhawk that defines the bearing from the drone to the GCS (and vice versa) and RF switching circuitry used inside the Pharos that activates the corresponding antenna within a few microseconds.
Please see the video posted in the previous page. It shows our drone flying at 350 ft, reaching a range of 10.6Km. It was streaming uninterrupted video to the GS and 2-way MAVLink telemetry the whole time. You can see the RSSI at the top right, just below the artificial horizon to get an idea of the quality of the link.
The set up used was a microhard modem connected to the Pixhawk directly through its TTL level serial port and an IP camera directly connected to the modem through the modem’s IP port. Very straight forward set up. The Pharos Antenna was used on both ends of the link (drone and GS) but with a single Pharos you should also get the range you seek for as Hugo mentioned.
It can be done using just one Pharos on either GS or aerial vehicle.
-Hugo
The goal of the Pharos antenna is to support not only aerial vehicles but any robotic platform that employs a 5.8GHz video streaming wireless data link. The outcome is that instead of getting a gain of (max. 1-1.5dBi) with your current omni 5.8GHz antenna (i.e. cloverleaf) you now get a gain of 10dBi. An additional outcome is that you can also stream telemetry through the same miniaturized modem (if you use the microhard modems) but this is optional.
The video below shows a 10.6 Km range for combined video and telemetry using the Pharos antenna and the 5.8GHz digital data link modem. There are many benefits using digital datalinks Vs Analogue but the one that works optimally for us is that we are able to perform various video processing techniques. For example, on the footage below we “georegister” the live video from the drone for improving the pilot’s spatial perspective of where the drone camera is looking at.
@Jason K The first units for Kickstarter backers are planned to ship October but we have included some contingency planning into the timeline. If the units are ready earlier (highly possible) we will ship them immediately.
@ Thomas Stanley-Jones From the dragonlink page you’ve submitted:
“NOTE: The Dragon Link system is for RC control only, it does not transmit or affect video transmission in any way.”
The Pharos antenna with the Microhard modem is a combined telemetry PLUS video streaming solution and fully compatible with the Pixhawk equipped drones. This is the smallest and lighter set up available that provides 10+Km of (telemetry AND video) range with minimized power requirements (current draw). The direct outcome is an increased flight time due to the compact set up and reduced weight.
I was wondering how your setup compares to the Dragonlink system?
@ Art The reduction in complexity is that you use a single radio (5.8GHz Microhard) and a single antenna (Pharos) on the drone side and exactly the same set up on the GC side for streaming both video and telemetry.
Every other set up requires one radio for telemetry and a separate radio for video on each side of the data link (a total of 4 radios and 4 antennas). Plus the link is digital now vs analogue video transmission allowing additional video processing applications to be performed (i.e. video tracking).
Another reduction in complexity is that you don’t need to use a motorized antenna tracker on the GS side as this is a fully digital tracking antenna.
So what you probably mean by “increased complexity” is the fact that you now have to plug a servo cable from the antenna to the Pixhawk AUX port (as what happens inside the antenna is transparent to the user).
The set up above will give you 10+ Km for both telemetry and digital video. This is a fact.
The biggest weakness of the 900 MHz frequency is the limited amount of unlicensed bandwidth in the spectrum. There is only 26MHz of available spectrum, where other frequencies have as much as 3 times the amount of available spectrum. In some cases, this will result in a lot of noise from other products operating in this spectrum range. Additionally, 900MHz is not an open public spectrum in most countries outside of North America.
You may transit 54mbps with the 900mhz radio, given you are the only one doing it in the area.
-Hugo
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