Greetings.
Im a noob here, and found this place oddly attractive as it has grown on me in the last hour or two.
I think this place is a positive thing for people like me with reticent yet burning ideas and thoughts on building and integrating systems and physical devices to achieve tasks and goals we have subsequently generated throughout the years.
In the short time Ive been loitering around and reading stuff here, things I have thought of or wanted to do but never reached the initialization stage now seem to be spawning again in my mind like mushrooms fertilized with magic poop.
So, what lead me here in the 1st place is my current activities in aviation and science involving UAV/UAS operations, an offshoot of decades of interest and involvement flying RC aircraft and rockets.
In recent years the RC world has been rapidly set aflame by the advent of cheap, readily available, and previously out-of-reach electronic components that enable piloting RC aircraft from a ‘pilots perspective’ or ‘first person view’ (FPV)
This involves mounting one or more cameras on the aircraft, installing video transmitters for the downlink to ground station (GS) monitor screens so you are looking out the front of the craft as would a pilot, offering breathtaking and entertaining flight experiences. Increasingly, the onboard gear includes telemetry data fed into the video downlink as an overlay, much like any ‘heads up display’ (HUD) would…Altitude, Airspeed, Temperatures, Battery or fuel remaining, Compass heading, GPS lat/lon, Attitude (bank,pitch,yaw) indication… you get the picture.
Its all so incredibly dynamic and enjoyable…until…you lose telemetry link, loss of command control, or any other combination of link-loss up to full blackout and the feeling of pissing your pants.
No I havent lost anything due to these circumstances, but have encountered the glitches and momentary scares of video loss or other ‘single subsystem failures’ that have halted the heartbeats for several seconds until system status normalizes and the aircraft is back safely on the ground again.
AS you can probably discern by now, integration and communication link quality between various subsystems is paramount. Most of the commercially available FPV gear currently available to the general public is proto-typey or otherwise rife with inconsistencies and associated bugs or characteristic limitations.
Now, about my approach and intentions to FPV operation…
Ive flown RC since I was a kid, and flown RC helicopters since 1987 when I was the ripe old age of 17…when the cheapest and easiest was a $1000 GMP cobra or cricket, powered by nitro burning piston engines, rather big, and made mostly of metal still. So Ive got skills to pilot, and fly full-sized helicopters these days as well ( the RC choppers are harder to fly )
This advent of FPV has recaptured my intrest in flying the little stuff again, as this FPV stuff was the stuff of fantasy back in prior years. The gear is light enough, cheap enough (but, you still “get what you pay for”), and available enough to attract many newcomers, spawning a brisk and vibrant new quasi-industry rooted in the old world of hobby RC.
Now, enough prefacing and rambling, lol, I will turn heading to get to the crux of this post here.
The failure rates, crashes, lost aircraft, bad experiences experienced by the minority percentage of FPV hobbyists mostly revolve around (you coulda guessed it) com link failures… loss of radio signals to or from (or both) ground station (GS) and aircraft.
With the FAA considering seriously the operation of small federal, commercial, and private (its true) UAV aircraft within controlled US airspace, with target date for implementing the rules and regs (limitation) of this coming phenomenon being 2014-2015, a groundswell of interest and lobbying is starting.
A vest, previously non-existent commercial industry is exploding right before us in the form of aerial surveys and aerial photography previously limited to manned aircraft, and associated expenses induced by limited availability of such services.
With small UAVs, these cost and availability limitations are quickly overcome, and will drive down the costs of such photography or survey jobs…opening up a much wider demand and market.
Now to turn heading directly to the target here…
Early adopters, those who get their s#!t together, integrate their systems and have the highest safety and reliability ratings will quickly become leaders in the market, able to get whatever certifications and ratings that will be required by federal authorities to commercially operate in this new arena.
Reduction of risk, minimizing sub-system failures, and maximizing operational range and scope of our UAVs becomes apparent to success here.
Most equipment available, as stated earlier, has the biggest limitations from legal limits of transmitter power and frequency scope. In the US, legal wattage for RC transmitters remains below 1 watt, limited also by the relatively small noisy segments of radio bands allotted for civilian RC use.
What struck me early on in my budding enthusiasm for FPV and possibly operating UAVs as a commercial operation, was the fact that Licensed HAM radio operators get a cornucopia of benefit in the form of greatly expanded radio spectrum options, and much higher legal transmitter power levels.
Being the old crusty Ham radio fanatic I have been (since the earths crust finally cooled) now suddenly brings unexpected and exciting returns. AS such, the knowledge of the fundamentals and dynamics of radio Hams inherently acquire give clear directions to solutions involving anything radio…and more important than raw TX power, is the generally misunderstood fact that your antenna design, implementation, and tuning -far far outweighs brute TX strength when considering signal quality;
So my project during this critical build-up phase involves setting up and operating Ham radio quality antenna arrays and supporting radio equipment, to provide range and operation scope magnitudes higher than anything available to regular hobbyists, even with their sometimes deep pockets.
Gosh! That silly Ham radio license finally pays off! lol
The central target to this improved coms link, and improved operating range is not just the increased power and capability of the various TX/RX gear I can legally use, but most importantly the antennas used to actually keep it all connected.
My current methodology involves some omni-directional antennas (always have omni’s ready even when using directionals)
plus the backbone supported by a directional “beam” antenna array. Using directional beam antennas obviously increases range big-time, but also includes the requirement of aiming the array constantly at a moving object…in the sky…
My prototype array now used to be on my roof used for talking to UHF and VHF stations, repeaters, and low earth orbit (LEO) Ham relay satellites. (AMSAT.ORG) …but now…oh boy! …they have a much more prolific opportunity as parts of the developing quasi-mobile GS equipment that is tracking and controlling my UAVs. Now to finally focus in close on the holy-grail of this endeavor… the use of a dependable and accurate antenna tracker to automate the positioning of the beam array becomes my priority, as I already have the selection of supporting radio gear for the GS and UAVs picked.
On youtube there are many varying grades of homebrew and commercial antenna trackers to be seen. Many even feature ,as their central character, Arduino based controllers stepping motors for X/Y pointing of directional antennas.
Some are pretty cobby, a few are fking brilliant, and the rest are commercial/military grade that cost more than my car.
Ive got the fabricating skills and electronics background to weld up a really nice 360 degree-H / 180 degree-V pan and tilt mount with belt driven stepper motors, and work out the best antenna arrangement possible (within my budget)…but it depends on a couple variables here. I know what bands of operation I will use already, and roughly the combination and phasing of the mix of antennas in the proposed array, but the positioning / aiming architecture to be chosen is still pretty foggy. Its going to depend on a couple things…will the onboard GPS telemetry sent back from the aircraft be used for positioning the array? … or will some other form of passive vectoring based on detection of signal heading be used?
Of course, Im just a little bit ahead of myself here asking about ideas, I 1st have to decide these last questions before anyone can be expected to make useful suggestions. It seems though that 1st determining what options I can generate for this aiming system might nudge the final choices into place.
So, since I absolutely love the employment of micro controllers for any form of useful real world work, and currently have a crush on the little Arduino controllers, Im leaning toward creating something novel and clever to get this job done.
As most of you already must know, creating or at least spinning a solution thats not exactly provided by someone else is indeed a savory and attractive conclusion to any need. Especially if you get a real great flash in the pan, and do something really unique…
As most know, theres always a different or alternate solution to any problem.
So…thats how I wander into this unexpectedly delightful den of grinders and hackers that has also re-incubated the latent yearnings of long fossilized curiosities and seeds of invention. My problem now is keeping my focus firmly on this antenna tracking goal, and not allowing myself to be overcome by sudden urges of going in too many directions with too many non-related automation / electronics distractions bubbling to the surface…heh
So, if you’ve read along to this point, I appreciate that!
And, knowing basically this solution required, and the way Im wanting to lean with it, maybe some Arduino mavens or even arm-chair spectators might know of related software / hardware configs they might have seen or experienced 1st hand that you may be able to mention. This would greatly improve my guidance and choices.
Really, its looking like if I dont figure out a neat passive tracker that wiggles around at intervals to determine best signal strength from some beacon or aux telemetry source on the aircraft, it will end up being something to take GPS lat/lon from the commercial Telemetry unit onboard UAV and point the antennas with it…
Lots of that out there, but I like the idea of not as much dependence on fickle Telemetry as that sub-system is one that fails quite often…leading to more critical situations as the antenna tracking is central to everything else too, including commands from the GS, and the ability to even take manual control of the aircraft in the event of a cascading comms / command failure.
Again, thanks for even reading this. As you can tell, this is something Im deeply involved in and even more enthusiastic about… or I wouldnt write multi page documents about.
Keep the solder on the target, and the bridges across the river… and not the other way around!