Full sky camera for aerodromes

[RFguy]

I am building a full-sky camera for YCWR. 

It comprises of a 200 deg fish eye lens 5 MP camera (AUD$50)

and a Raspberry PI 3 or greater. ($50)

and a small fan .  

It mounts in a radome- PVC pipe and neutral density filter so the sun doesn't kill it. 

We'll see how that goes WRT sun blooming. 

The 200 deg camera permits it to slightly below horizon. this assists calibration. 

I'll put a graticule on it in squares of something like 15 degrees. 

got to work on the ND filter to get that right- compromise in light level sensitivity and getting blown away by the sun.

with a 200 deg elevation x 360 azimuth  coverage, that is  23,000 'square' degrees. A 5 MP sensor will yield pixel resolution of approx 20 seconds (I think). depends on what the lens does, cheap lens it wont be perfect.

Because it is a Bayer colour mosaic, there the colour of a single pixel is made up of at least the surround 9 pixels, (3 in any direction), resolution is about a third, or 1 minute of arc. And in practice, because it is a 1/4" sensor and cheap lens, probably a few minutes of arc. Still good enough !

 

but it will be good enough to figure out cloud coverage and heights because it can see the horizon and it can see the hills (of known heights) (or not see them) .

 

https://www.aliexpress.com/item/32847072721.html?spm=a2g0o.store_pc_groupList.8148356.24.62d34fddaPjzf1

 

this is not a USB camera- has a MIPI interface for direct cable connection to the PI or Nvidia Nano .

 

going to have to find a suitable > hemispherical ,ND filer,  UV proof dome for it. 

 

For connectivity :  Ideally we would use a PoE (power over ethernet cable) so it could be plugged into the office internet and get power up the cable. It will need ferrite beads on the cable at each end (6 of them) so it doesnt generate RF interference. 
.

there is a raspberry PI poe HAT

https://www.raspberrypi.org/products/poe-plus-hat/

 

OR a wifi Dongle ($5)plugged into USB  and run power up to it, so that it can just need 12VDC run up to it, and it can connect to any WIFI without wires. 

 

or a 4G modem and power run up . (more expensive solution.....)

 

Edited July 5, 2021 by RFguy

[Old Koreelah]

If you need somewhere to test it, YQDI needs a camera and our neighbour is building a new hangar, the perfect mounting point.

[Kenlsa]

Good one Glen,

Airfield cameras are great for us.
Early in my flying, unless I could phone the strip so as to ascertain local conditions, I was hesitant to visit.

With more and more cameras installed it will sure help safety.

Ken

 

[mkennard]

Once you have it working, don't forget to submit them to Avplan and Ozrunways.

 

There is also this if you didn't know.

 

https://myairportcams.com

[RFguy]

In theory, and this is what I used to do in other fields, the RaspPi could transmit a picture using SSTV on 123.45 etc so you could see the image on your radio using a tablet, phone (audio in , or other display...) take about 24 seconds for a  colour image.... (Y, CrCb)

 

 

Edited July 6, 2021 by RFguy

[Kyle Communications]

Not sure you will be allowed to do that Glenn. I dont believe data type signals are allowed on the band

 

[RFguy]

hmm that is true. UHF CB then . 

[Kyle Communications]

Cant do it n UHF cb either...ch23 is for data only but must be in selcal format

 

[RFguy]

Actually Mark, that is not  quite true.  Ch 22 and ch23 are available.  and you could wing it to fit within the definition of " telemetry and telecommand:" . The latest act https://www.legislation.gov.au/Details/F2017C00476 just says non voice only, the references to telecommand and data are on the ACMA website but they didnt change when the act changed from the 2011 version... HOWEVER, there are strict duty cycle limits. But I never heard them enforced. UHFCB is the wild west

Anyway, the discussion here is about  remote , viewable full sky cameras. 

The hardest thing I can finding is a suitable hemispherical ND filter, that is also UV stable. The ND filter dome cameras do not light UV....
Ideas ?

[Kyle Communications]

I have been getting stuff together to make the airband voice recorder for Caboolture airfield. Its been a interesting time looking at all this stuff. if most of it was arduino based it would be a lot better for me because the Pi stuff I dont like at all. Its all ok for you software gurus but it just doesnt stick in my head

 

 

[RFguy]

Some experiments performed.
I am going to use exposure stacking to deal with the sun.
We do about 10 frames over a second, each at different exposures.
An HDR algorithm weights and combines each one to maximise dynamic range.

Should look pretty good. even with the sun boring down a few of the pixels. 

 

Will be mounted in a 6" poly pipe , and some drainpipe clamps.. 

 

found some 150mm tinted domes. The trick will be finding a dome material that minimises blooming and flare from the sun.  some video/camera people might chime in here with suggestions ?