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Uni Edition

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Linar Yusupov edited this page Sep 19, 2024 · 45 revisions



Uni Edition has taken it's name as an abbreviation of "Universal Access Transceiver" (UAT), which is one of ADS-B standards that operates at 978 MHz aviation radio band. Despite "transceiver" word being used in previous sentence, this particular SoftRF device does NOT transmit anything on the 978 MHz band (dedicated for certified aviation equipment). Only receiving capabilities of the device are in use.

Important

Purpose of this SoftRF Edition is NOT for new users!
Instead, Badge, Prime Mk II, Prime Mk III or Dongle Editions are recommended for you to start with.

Uni Edition is for those of current SoftRF users who are already familiar with other devices and ready to spend own time and efforts to evaluate if unique UAT ADS-B reception feature works appropriately for his or her needs.

Uni Edition is based on third-party's hardware - TI SensorTag LPSTK-CC1352R development kit, which is available for direct purchase from manufacturer at more or less reasonable price - 30 USD (plus shipping).

Compatibility 1

Type Protocol FLARM OGN tracker PilotAware Skytraxx SoftRF
Radio

UAT 978
ADS-B

2
  FLARM AIR V6

 

OGNTP

 

P3I

 

FANET+

3
 

SRD 860
ADS-L

Data FLARM NMEA

  Garmin GDL90

 

Dump1090  

1 - it is necessary for a reader to distinguish the difference between statement "compatible" and statement "fully compatible".
     SoftRF implements only a reasonable minimum of the protocols specs. No "bells and whistles" so far ;
2 - reception of traffic 'downlink' frames only ;
3 - valid for Uni Edition with optional SoftRF LoRa module.

Comparison with Prime Mark II

These are key features to distinguish Uni from other SoftRF Editions :

  • UAT (ADS-B 978 MHz) reception and decoding is it's built-in functionality ;
  • TI Sensortag is FCC, CE and IC certified equipment ;
  • it is manufactured and distributed by world famous Texas Instruments brand ;
  • LPSTK-CC1352R is a retail product that comes with a nice, factory made enclosure ;
  • it is designed to be powered by hazard-free AAA battery cells ;
  • easy to install or revert device firmware by means of Bluetooth LE OAD smartphone app.

However, there are few features missing, such as :

  • it does not have a built-in GNSS receiver ;
  • no built-in Wi-Fi nor 'classic' Bluetooth ;
  • unable to operate with FANET protocol (it uses LoRa modulation) 'out-of-the-box' .

Certificates

TI SensorTag has the following certificates of compliance :

It means that this device is approved by corresponding agencies for:

  • land use and
  • with genuine factory firmware only.

ADS-B Out remark

No doubts that an amateur-built non-certified low-cost ADS-B transponder is possible.
It was shown to public by our own "proof-of-concept" study for :

However, as a certified and instrument rated pilot with 20+ years of experience, in no way I will give a tool for every looser in the world, all he/she can afford is to spend 30 USD for the TI SensorTag, to abuse the ADS-B technology and compromise my own flight safety and flight safety of every other air law abiding pilot.

SoftRF firmware does intentionally exclude every possibilities to transmit anything on 978 MHz radio frequency.
Any attempt to contribute the transmit feature into SoftRF from aside will be blocked at very early stage.

Use cases

Receiver

UAT Receiver makes reception of UAT signals, then transmits serial data frames over UART @ 2 Mbps.
This data rate and format of the frames were choosen to be compatible with Stratux UATRadio, Low Power v3.



Receiver function is better explained on a separate page.

Bridge

Purpose of the UAT bridge is to receive ADS-B traffic information on UAT (978 MHz) aviation frequency,
then to re-broadcast the data using one of supported RF ISM band protocols.

Bridge function is better explained on a separate page.

Solo

We assume that you are already familiar with Dongle and Prime Mk II Editions.
In Solo use case the Uni is operating exactly the same way as other Editions do:

Radio UAT Air V6 OGNTP P3I FANET+ SRD 860
ADS-L
Receive

 4
Transmit

 

 4

4 - valid for Uni Edition with optional SoftRF LoRa module.


Data Stratux NMEA GDL90 Dump1090
Input

Output

Procedure of settings change is similar to that the Dongle has.
Settings description is located here.

Important

EASA ADS-L radio protocol selection is not applicable for current version of SoftRF Tool app for Android - use Online Tool method instead.

Hardware dependencies

Firmware variant USB to Serial adapter GNSS module Pressure sensor OLED display Wi-Fi or BT or BLE adapter
Receiver Required Not required Not required Not required Not required
Bridge Required 5 Highly recommended 6 Recommended Not required Not required
Solo Required 5 Required Recommended Recommended Recommended

5 - 'USB to Serial adapter' is in use by Bridge and Solo variants for the purpose of troubleshooting and settings change only ;
6 - bridging of UAT traffic into "Air V6" radio protocol needs accurate timing and true own position data to operate properly. It will NOT function in '"Air V6" option without a GNSS source. OGNTP, P3I and (optional) FANET bridging should be fine (in EU region) without GNSS.

Known limitations

  1. reception of UAT signals is currently limited to "downlink" (air-to-air) packets only. So, realtime weather and other "bells and whistles" of the UAT protocol are not available ;
  2. "Stock" TI SensorTag has built-in passive HF filter to meet FCC compliance. Because of that, sensitivity @ 978 MHz is a bit reduced.

Disclaimer

SoftRF firmware for Uni Edition is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Author of SoftRF firmware:

  • will reject any hardware related claims associated with TI SensorTag development kit. Ask for support from seller or manufacturer ;
  • reserves the right to suspend or terminate support of TI SensorTag in the firmware at any time.

For the time being ( July '20 ) there were no critical hardware issues reported for current version of the SensorTag kit. However things my change over the time...
If you have issues with bringing up your new TI SensorTag or just not happy with the board - be prepared to execute your Purchase Protection plan.

Bill of materials

Required

Number Part Qty Picture Source
1 TI SensorTag LPSTK-CC1352R 1 TI Store
2 CP2102 USB 2.0 to TTL UART serial converter 1 AliExpress

GNSS

Number Part Qty Picture Source
1 'noname' NEO-6M GPS module 1 AliExpress

This GNSS module is one of the most basic ones that is known to work good enough.
However, you may consider to read this guide while looking for an alternative.


Battery

AAA Ni-Zn (1.6 Volts) is the only battery type applicable for Uni Edition.
It is recommended to purchase an appropriate Ni-Zn charger as well.

Number Part Qty Picture Source
1 AAA Ni-Zn battery cell 4 AliExpress

Recommended

Number Part Qty Picture Source
1 TTGO 0.96" I2C OLED display 1 AliExpress
2 Bosch BMP280
pressure
sensor		 1 AliExpress
3 Bluetooth
HC-05		 1 AliExpress
4 Serial WiFi v1.0 1 AliExpress 1 2 3 4 5
5 Antenna
868 MHz 7 		1 EBay
AliExpress 1 2

7 - 868 MHz variant is applicable for these world regions: EU, RU, NZ, SA, IN ;
     915 MHz - US, CA, AU, IL, KR ;
     433 MHz - CN .

Wiring

Receiver

This use case needs no changes to be applied to the SensorTag's PCB.

Bridge

It is recommended to solder a wire between pins 21 and 1 of SensorTag's pin header in order to supply 3.3 Volts power to a GNSS module.

Solo

Solder additional power supply and ground wires in accordance with this illustration:


Periphery connections

Type Thumbnail Details
Serial Full picture
USB Full picture
Bluetooth Full picture
I2C Full picture
OLED Full picture
Sensor Full picture

Firmware

Depending on your use case, you need to choose an appropriate file from Receiver, Bridge or Solo SoftRF firmware binaries.

SoftRF firmware installation and update is performed by Bluetooth Low Energy "over-air-download" (OAD) method from a smartphone/tablet with Simplelink SensorTag (Android) or TI SensorTag (iOS) application.




For details, please, read this page.

Antenna

Sensortag's 'stock' antenna is definitely NOT the best one for 868-915 MHz band:

It is Ok to begin with but it makes sense to further transit onto a better one.
Depending on your geo location and protocol preference you may think about to use a dedicated 868, 915 or 978 MHz antenna from a trustworthy source.

Enclosure

TI Sensortag comes with nice molded plastic case and rubber-like dust cover :



However, if you need more space for your external hardware options - please, consider to use 3D design of 'Sleeve' extension for the SensorTag enclosure :



STL files of this enclosure are available. For details, please, read this page.

Battery life

Major power consuming component of the Uni Edition is a GNSS module being used.
Below are measurements have been taken with ublox 8 based GG-1802 GNSS module :

GNSS Not connected Acquisition Mode Power Save Mode
Avg. current

10-15 mA

50-60 mA

25-35 mA

Operating time from a full charge depends on your actual battery capacity.

Optional equipment

SkyView EZ is a DIY companion device for SoftRF Uni Edition.

   


Hardware

SoftRF

SkyView

Flight Recorder

Adapters

Software

Firmware

Tools

Protocols

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