This month’s update is hereby christened the update of “soon”, after all the stuff that is almost (but not quite) ready for primetime. Here’s what we’ve been up to this month!

• Hardware
  • GS3M PoE Preorders Shipping Soon
  • ADSBee m1090 Eval Boards Available for Backorder
• Firmware
  • Firmware 0.9.0 RC4
  • 0.9.0 Stable (Soon)

🔧 Hardware

📦 GS3M PoE Preorders are Shipping Soon!

After some final tweaks to the IP65 enclosure design, initial preorders for the GS3M PoE are on track to begin shipping this week!

I’ve had an early prototype of the GS3M PoE on my roof for a few weeks, and it’s been doing quite well with the standard set of 2.2dBi waterproof dipole antennas. I’ve seen ranges in excess of 150 nautical miles and over 100 aircraft tracked simultaneously, which isn’t bad considering that it’s on top of a single story house with some pretty substantial hills and structures in the surrounding area. Long coax cables really do stack up quite a lot of loss at the frequencies used for ADS-B (1090MHz / 978MHz), so putting the receiver right at the source like the GS3M PoE does provides quite a bit more flexibility for meeting antenna gain requirements.

I’m looking forward to seeing how GS3M PoE units fare in the field! If you pre-ordered a device, keep your eyes peeled for additional installation information (including tips about waterproofing cable runs) that will be posted and forwarded to you before your unit ships. New orders placed today are expected to ship by mid to late December.

🧩 ADSBee m1090 Eval Boards Available for Backorder

Demand for the ADSBee m1090 Eval boards has temporarily outpaced my ability to assemble them, but we have another batch coming together in the next week or so. If you’d like to try out an ADSBee m1090 module, don’t hesitate to place a backorder! Units will be shipped in early to mid December.

💾 Firmware

Firmware Version 0.9.0-RC4

ADSBee firmware 0.9.0-rc4 is currently live! The release notes bury the lede a bit on how much has improved since last month’s release candidates, since RC4 is a quick hotfix applied over RC3, where the real meat and potatoes were cooked.

I spent a solid week retooling much of the ADSBee’s preamble detector and demodulator architecture, and made some key improvements to both the PIO assembly performing demodulations (limitations on maximum clock skew, faster recovery time while matching preambles), and the overall PIO architecture (a whole extra high power preamble detector / demodulator state machine added to both the ADSBee 1090U and ADSBee 1090). Collectively, these improvements have created a moderate but noticeable improvement in valid packets received per second for a number of our beta testers, including fewer packets dropped at close range (this is where the extra high power preamble detector / demodulator pair helps out most).

In addition to the PIO improvements, firmware versions RC3/RC4 introduce a new position filter for TIS-B (Traffic Information Service – Broadcast) aircraft positions received via 978MHz. I originally operated under the assumption that TIS-B positions would be quite reliable, since they are generated from radar tracks received by FAA ground stations, but in practice these positions tend to jump around quite a bit, causing aircraft to “hop” around on local receiver maps fed by the ADSBee. This hopping issue was only relevant to maps being fed with decoded locations by the ADSBee, like Foreflight and Avare, and is not present in online receiver maps like whereplane.xyz or airplanes.live, since those maps use readsb as a backend, which receives raw packets instead of decoded locations and performs its own filtering.

Firmware versions RC3/RC4 fix this issue by implementing the same velocity-based position filter introduced way back in firmware version 0.7.4 (architecture originally designed by @error414), and adapting the filter to work with UAT formatted aircraft positions instead of Mode S formatted aircraft positions. From my testing, this has quite nicely solved the hopping issue, and aircraft tracks received via TIS-B over UAT are now displayed with consistent trajectory updates on local maps.

Firmware Version 0.9.0 Stable

0.9.0 stable is still on the way! The original hope was to get it out the door in mid November, but some of the retooling for RC3/RC4 took longer than expected. The good news is that it should be ready this month. Here’s what’s left on the to-do list:

• GDL90 forwarding of UAT uplink packets (allows FIS-B data to be forwarded to Foreflight for tablet users in aircraft with UAT transponders).
• 1090MHz Mode S ground position decoding (so local map users can see aircraft that are taxiing).
• Web UI local map

Stay tuned for one or more release candidates before the official stable dual band firmware release! 🎉