Portable ADSB receiver


#1

Here is the final(?) version (Version 2) of my portable ADSB receiver. The main design criteria was it had to be smallish and reasonably easy to deploy. Version 1 had a DVB-T dongle, I’ve recently upgraded it to the ProStick & Filter combo with quite pleasing results in terms of range increase.

Its powered by a TP-Link POE injector and hooks up to a TP-Link pocket router/WAP & 4G/LTE USB modem combo so it can get time sync and I can access it via wifi on my laptop or iPad.

I have a longer piece of conduit and coax if I want to get the antenna a bit higher.

Andrew

https://dl.dropboxusercontent.com/u/13402116/IMG_6217a.JPG

https://dl.dropboxusercontent.com/u/13402116/IMG_6218a.JPG

https://dl.dropboxusercontent.com/u/13402116/IMG_6233a.JPG

https://dl.dropboxusercontent.com/u/13402116/IMG_6234a.JPG


#2

Nice set up. I’ve started thinking of a portable setup myself as well.


#3

Nice. I have a similar case for portable AIS, but thinking of adding ADSB as well.

/M


#4

Add a GPS module (and run gpsd) and piaware will pick up the current location for mlat automatically


#5

My question and the admin’s response on another data sharing site XXXXXX:

My Question:
Would XXXXXX use my data for MLAT calculations if I add Adafruit GPS HAT to my Pi2?

XXXXXX Admin’s Answer:
No. We tried this in the early days and it was so variable that it had no benefit over the “clock” in the receivers.
We timestamp within the FPGA as soon as the signal hits the front end, same place, reliably every signal.


Plane Finder Radar Receiver - possible FPGA/GPS bargain?
#6

The USB bus is too variable for time stamping. Even GPS units that provide somewhat accurate NTP time use the serial port for accurate timing. I have done this with PCs and RPIs. It would help if the dongle connectivity had reliable timing (maybe PCI).

My radarcape is an FPGA unit. It uses the FPGA for GPS/GNSS decoding and ADS-B decoding. It has time stamps that are about 8-10 times better than the internal clock on the STD RTL-SDR Dongles.

I believe that version 3 can use GPS for position location.


#7

Not relevant, because you misunderstood what obj is saying. The GPS is just to automate the “own position”, so we don’t have to manually re-configure the receivers position. It can not be used for mlat timing.

/M


#8

You are right. GPS is used for
(1) Location of Receiver
(2) Time Stamp

What obj recommended is installing GPS for receiver’s position, as mobile receiver has dynamic location.
What the other site XXXXX referred to was time stamping by GPS.

I really appreciate Flightaware that they could manage to calculate quite accurate position of mlat planes (with very little jerky motion/zigzagging), using DVB-T dongle’s/Pi’s clock, without GPS support.


#9

Right, that’s exactly what I meant, sorry for the confusion there.


#10

How often does it update? Can we use it in a moving car? Boat ? (under way, I mean)

And, most importantly, could gpsd-support possibly find its way into mlat-client also… :slight_smile:

BR /M


#11

gpsd will give piaware updates once a second; piaware pushes them upstream every 5 minutes or after approx 0.1km movement, whichever happens first. It’s meant to handle the car/boat situation but so far it’s only been tested in stationary environments.

There’s no mechanism to push location updates in vanilla mlat-client / mlat-server at the moment.


#12

I had thought of that Oliver, trying to work out how to get the NMEA via GPSD to set the lat/lon in the dump1090 config. However, as this unit is purely for me to look at the local dump1090 webpage when I’m not at home (I haven’t got it runiing piaware or feeding either FA or FR24) its just as easy for me to quick SSH in and edit the config files.


#13

gud


#14

If you don’t have GPS and don’t care about MLAT, can you put a piaware feeder in your car and drive around with it feeding ADSB locations to FlightAware (through a cellphone hotspot for the data)?


#15

Sure, just disable mlat first so it doesn’t try to use an incorrect location.


#16

Just for kicks I think I’ll have to try this. What’s the best way to disable MLAT these days with dump1090-fa and piaware 3.3.0?


#17

piaware-config allow-mlat no && systemctl restart piaware

Or change the mlat setting on the stats page then restart piaware


#18

I’m thinking of making one myself one, do you have a link to the case and the instructions for the antenna?


#19

Hi,

The case is a cheap copy of a Pelican (http://www.pelican.com/us/en/product/watertight-protector-hard-cases/small-case/standard/1120/) .

Unfortunately, the antenna was one that came up on eBay in very limited numbers some time ago and hasn’t been seen since …

Cheers.


#20

Wow, I like those Pelican cases, never heard of them before. Pretty cool, but not exactly cheap. Made to protect expensive stuff, and in goes a rPi and a dongle :wink:

I always wonder how to make the holes for cables, with a standard drill?, and how are they waterproofed? And how do you secure stuff inside, hot glue, tape?