Live aircraft tracking

  • A link to track the state police helicopter, ABLE7:
    • Tail N607SP: https://globe.adsbexchange.com/?icao=a7e2de
  • A link to track the local Los Alamos-based Classic Air medical helos (they have two in Los Alamos as of 1/24)
    • Tail N407TK: https://globe.adsbexchange.com/?icao=a4c855&lat=35.874&lon=-106.240&zoom=11.7&showTrace=2024-02-01
    • Tail N407MZ: https://globe.adsbexchange.com/?icao=a4c7cd

Here, we:

  • Explain ADS-B aircraft tracking
  • Explain the value for SAR
  • Present a custom ADS-B build that has been used successfully at Incident Base for tracking helicopters

There are three required components in our setup for live aircraft tracking in the most remote locations:

  1. Starlink system to provide internet access via wifi
  2. A portable ADSB receiver system, configured to connect to the starlink, feeding tracking data up to the internet
  3. SARtopo software running on a laptop, connected to the internet via starlink, pulling tracking data from the internet

ADS-B stands for Automatic Dependent Surveillance-Broadcast. All aircraft (including the helicopters that assist with SAR) are required to transmit their live position over the ADS-B system. The FAA maintains their own receiver network to monitor these transmissions. We (private citizens/SAR) do not have access to that FAA network. However, private individuals (hobbyists) can install their own receiver stations (e.g. on the roof of their house) and upload the same tracking information via the internet to one of several online aggregators. There are different aggregators, and they do not share data with each other. A single receiver system usually feeds a single aggregator, although it can often be configured to feed multiple aggregators.

Some examples of the aggregators include:

The SARtopo mapping software can access the Open-ADSB data and display live aircraft locations on top of the map that we use for search management. If you have a premium account, you can view all the aircraft flying in the country right on the caltopo map.

To repeat: as far as we can tell, as of the beginning of 2024, SARtopo uses ONLY the Open-ADSB service. If the aircraft info is being fed to any aggregator other than Open-ADSB, SARtopo won’t show it.

The receivers to collect the ADS-B data from the aircraft have very impressive range. However they are also, like VHF radio, fairly limited to line-of-sight (the primary channel is at 1090 MHz). If the aircraft goes on the other side of the mountains from the receiver, it will drop off the map. Or if it drops down low.

So, where are these receivers? Well—only in locations where hobbyists have set up tracking stations. There is not good coverage across northern New Mexico, especially in the remote areas that we regularly conduct searches. For jets flying at 30,000 ft, it’s easy to maintain line of sight from an urban area a hundred miles away. But when the helicopter drops down low to perform a search pattern in the backcountry, it’s not likely to be in range of any ADS-B receiver.

However, we now have the technology to remedy this. Following the existing instructional info available, we have built a portable ADS-B receiver system that can be deployed alongside the Starlink and SARtopo.

There are numerous advantages to having live tracking of the helicopter.

  • We can watch which areas the helicopter is searching.
  • We can direct them to search areas that haven’t been yet covered.
  • We can provide real-time feedback to the helicopter crew whether they’re searching the correct location.
  • If they find the subject or a clue, we will have their live location already on the map.
  • We can observe the inbound helo location in order to prepare teams or time the evacuation.
  • We can document their search track.

Custom Build Details

I modeled my build after one done by “Mavericknos”.

Before you undertake this project, remember that it is dependent on having a starlink system to provide internet access. The ADS-B system uses the starlink to upload the data to the internet (where anybody can view it), then SARtopo pulls the data from the internet to put it on the map.

Also, before you go full DIY, know that you can buy a kit basically ready to rock. It may not have an antenna that mounts how you want, or a nifty way to power it like I use in my custom build, but it gets you most of the bits. Just remember that you want to feed Open ADSB for the SARtopo. Using the “PiAware” system to feed Flight Aware will not work. You can still buy one of the nice kits, but you may have to erase the pre-configured SD card and load on the Open-ADSB software instead (which you’ll have to do anyway, if you build it all yourself).

Components:

  • Raspberry Pi
  • Software Defined Radio
    • This is the key technology, this is the actual radio. There are lots of these available, of different quality, and it can be hard to figure out what’s junk and what’s not. Peter gave me the one I used in this build, but if I had to buy one I would get the PiAware one, as being of dependable pedigree.
  • Antenna
    • Here, you get what you pay for. Again, I recommend the PiAware one. You want the 1090 MHz.
  • 5 V 3 A power supply
    • You’ll need to power your system with 5 V, 3 A. The raspberry pi kits usually come with a wall wart. Regardless the source, it goes into the RPi with a USB-C connector as 5 V.
    • I originally built my kit so that it could be mounted to the top of my 50 ft tall antenna mast. Getting the power up there requires some careful choices. I elected to use a PoE (power over ethernet) setup. Basically, I plug a black box into the generator, I plug a 50 ft ethernet cable into that box, the ethernet cable goes up the mast (together with the coax for the antenna), and plugs into my custom box. Inside my box, I have a PoE box that takes the ethernet connector and spits out 5V on a USB-C connector that powers the R-Pi. (The SDR is powered off one of the R Pi USB ports.) That system is great if I want to get the antenna way high in the air.
    • I have since decided that I don’t like putting the custom box at the top of my 50 ft mast. Even though it’s not that heavy, it makes the top of the mast sway way more. Also, I usually put up the mast with the radio antenna right away; it’s extra work to put up the ads-b setup if it’s not necessary; but I don’t know that it’s necessary until the mast is already in the air, at which point I am disinclined from lowering it to add the ADS-B setup to it.
    • Instead, I mount the antenna down at ground level, either on a cheap light stand, or on the vehicle. I have yet to settle on my favorite mounting system. But I’m willing to take the decrease in range for the setup convenience.
    • Without the need to put it up the mast, there is little need for the 50 ft long e-net cable power setup. The RPi can be powered with the normal wall wart power cable, connected to the generator power supply.
    • Most recently, I have added the possibility for powering the box off of a Li-Ion battery, so that I don’t even have to have AC power in order to get it operational. I’m excited about this modification, though I haven’t tested it yet.
  • Weatherproof enclosure
    • I wanted to be able to set this up and leave it out in the rain. With the RPi and SDR though, one has to consider overheating and frying them. So I hacked out some holes from the front of the enclosure and glued in some vents. If the rain comes from above, it will drain off without entering the enclosure. If it comes from below, no guarantees.
  • Mounting System
    • As mentioned, I originally designed this to mount on my fiberglass antenna mast. The easiest way to do that was with a piece of PVC pipe that slides over the top end of the mast. I am reconsidering mounting options more conducive for mounting on the car (maybe a magnet on the base, then slap it on the hood).

UPDATE 2023:

  • It proved cumbersome to put the unit at the top of the mast (45 ft up in the air) and also completely unnecessary. So now I just put it on top of a 6 ft tripod at base. The receiver + antenna is super sensitive.
  • It proved cumbersome to power the unit through the PoE ethernet cable + injector brick + AC power, so I switched over to a simple Li-Ion battery. To power it on now, one just plugs in the battery and that’s it. It will run for days on a single battery.
  • Apologies, the updates to the system are not reflected in the photos below.

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