Sunday, June 5, 2016

acarsdec on RPi3

Getting ACARS decoding going on a Raspberry Pi 3 turned out to be relatively trivial.  I followed the instructions here. (Cool site, poke around.) Note the current version of acarsdec is 3.2 and I had to edit Makefile as documented to use rtl decoding only.

Took less than an hour, even with my cat Dora's 'help'. 

Apparently acarsdec CPU use was a concern on the RPi2. Just for grins I started arcarsdec with 6 frequencies instead of 4 and the CPU isn't even breaking a sweat.


Some sample decodes:


[#1 (F:131.550 L:-38 E:0) 05/06/2016 19:31:28 --------------------------------
Aircraft reg: .N355NB Flight id: NW1597
Mode: 2 Msg. label: 30
Block id: 5 Ack: !
Msg. no: M25A
Message :
051930 KMSP KPHL3
          A
GOOD RIDE SOUTH OF CLE.
TOPS AROUND FL370


[#5 (F:130.450 L:-22 E:0) 05/06/2016 19:50:45 --------------------------------
Aircraft reg: .N913AN Flight id: AA1201
Mode: 2 Msg. label: H1
Block id: 9 Ack: !
Msg. no: D74A
Message :
#DFBTRP 195022  40.9289  -81.3999 369 145.4 451   1474 0.01376
  81.00 -104.06 1.008  0.976  0.000 -0.015 -46  0 00 01 248 8    1382


[#6 (F:131.125 L:-32 E:0) 05/06/2016 19:59:01 --------------------------------
Aircraft reg: .N362NW Flight id: NW2811
Mode: 2 Msg. label: 39
Block id: 4 Ack: !
Msg. no: M86A
Message :
051939 KDTW KDCA3
2040

WCHR
ELEC CART
AISLE CHR
UM


I'll let this cook for awhile and see what I can do with the output next week.

Saturday, June 4, 2016

More Fun with ADS-B and ACARS

The release of the Raspberry Pi 3 got me going with aircraft tracking via ADS-B again. I took down my outdoor active HF antenna (which didn't really do much for me) put my ADS-B antenna back up, got a FlightAware Pro dongle and reinstalled the FlightAware software on an RPi3. Works as designed. Lots of CPU headroom. I didn't install anything else, like VNC, and the RPi3 runs for weeks at a time. Probably longer if I'd leave it alone. The RPi2 I was using before had to be rebooted daily. I think dump1090 and the FlightAware software like to have the place to themselves.

I'm not sure if the FlightAware dongle made any difference in my particular case but for $17, what the hey. It's orange and that's enough for me.

The RPi3 fits in the fanned aluminum cases I like to use and the WiFi works through the case, at least at <30'.

RPi2 images do not work but I've done the install so many times another install was trivial. 

In the spirit of getting small, I acquired an Intel Compute Stick, second gen, w/Intel Atom x5 and Windows 10 32-bit. I put Virtual Radar Server to display aircraft tracks and ProScan scanner software on it. I run it headless and access it via VNC. It's a Windows PC, nothing special.  I tried SDR# but it pegged the CPU enough to make the Stick PC inappropriate.

But it has enough horsepower and connectivity for what I got it for.

I also run a client for adsbhub.net on it which allows me to display flights from various parts of the world. Very cool. If you have a VRS setup I encourage you to check out adshub. If you don't have a VRS setup I encourage you to get one and then check out adshub.

I whine, moan and bitch a lot so when something works I try to dwell on it. FlightAware, VRS, and adsbhub are free, easy to use, have friendly people involved and if you're an aviation and/or radio buff an absolute blast to use.

I've been playing with decoding ACARS on HF with PC-HFDL for awhile now. Works like a champ on HF but I haven't been able to decode VHF ACARS on it yet. I played around with ACARSD a little but it seems pretty hard to get it to decode consistently.

HF ACARS is interesting. Long range, I can decode transmissions from 100's of miles around. I'm still working on interpreting the messages. Here's a sample.

[HFNPDU ACARS FM GND TO AIR 59]
<SOH>2.G-VRAY9_<DEL>Y<ETX>;+<NUL>
[Preamble TS(4) 300  bps 1.8 sec Interleaver FREQ ERR 9.69 Hz Mag 30 Votes 8 ][OK]
[Preamble TS(0) 300  bps 1.8 sec Interleaver FREQ ERR 9.09 Hz Mag 22 Votes 32 ][OK]

[MPDU 01:01:19 AIR CPA890 SLOT 4 300 BPS ]
Nr LPDUs = 1 Ground station ID RIVERHEAD - NEW YORK NOT SYNCHED
Aircraft ID 3A
Slots Requested medium = 0 Low = 0
Max Bit rate 1800 bps U(R) = 0 UR(R)vect = 0
[HFNPDU PERFORMANCE]
01:01:16  UTC  Flight ID = CPA890  LAT 42 13 4  N  LON 81 3 59  W 
Performance version 18
Flight Leg 47
GS RIVERHEAD - NEW YORK
SYNCHED TO UTC
Frequency 6
Previous Leg lost count 0
Current Leg lost count 0
Previous Leg Number of sec disabled 1010
Current Leg Number of sec disabled 356
Number of MPDUS received O.K
1800 bps = 0
1200 bps = 0
600  bps = 1
300  bps = 56
Number of MPDUS received in Error
1800 bps = 0
1200 bps = 0
600  bps = 0
300  bps = 0
Number of Squitters received O.K = 131
Number of Squitters received in Error = 0
Number of MPDUS transmitted
1800 bps = 0
1200 bps = 0
600  bps = 1
300  bps = 5
Number of MPDUS received first time
1800 bps = 0
1200 bps = 0
600  bps = 1
300  bps = 5
Reason for last frequency change = No Change Since Last PD HFNPDU, vendor code 2


And then there's PlanePlotter. Real nice people, the support couldn't be better. But the software 'thinks' way different than me. The layout, the options, the dependencies all just confuse the crap outta' me. Even the web site makes me dizzy. And the end result once I got it going was a real let down.

But all the cool kids are using it so naturally I got a copy to abuse myself with.

I wanted to plot flights decoded with PC-HFDL with PlanePlotter. The end result was a crappy gif map image. Even freeware like DUMP1090 (which displays ADS-B information, not ACARS) does better than that.

In all fairness this is a relatively new area of interest for me so I'm sure I'm doing it wrong. (Relative to Marconi and the Wright brothers, but I'm trying to be kind.) I'll take another stab at it

My next project will be setting up a multi-channel ACARS decoder on an RPi3.

Ultimately I'd like to have  one display, like VRS, with HF and VHF ACARS data bolted on.

Links to my Virtual Radar Server and scanner web pages are on the right. VRS will load in most browsers but the customizations require Google Chrome. And since I'm on Time Warner Cable, please be patient. I have like a 1.1 Mbps upload speed for whatever reason.

Also, if there's a problem I may be 'tweaking'. 


Overall, much YAY!