ADSB.md

ADS-B

Automatic Dependent Surveillance Broadcast is an air traffic surveillance technology that enables aircraft to be accurately tracked by air traffic controllers and other pilots without the need for conventional radar.

Current state

OSD can be configured to shows the closest aircraft.

OSD ADSB Info element

• "-" no ADSB device detected
• "H" IMU heading is not valid
• "G" no GPS fix or less than 4 stats
• "[Number]" count of ADSB aircrafts

OSD ADSB Warning element

OSD can be configured to simple view (one line) or to extended view (two lines) by
set osd_adsb_warning_style=EXTENDED

Simple view

{distance to vehicle} {direction to vehicle} {altitude diff}

Extended view

{distance to vehicle} {direction to vehicle} {altitude diff}
{Emiter Type} {Vehicle direction} {Vehicle Speed}

Hardware

All ADSB receivers which can send Mavlink ADSB_VEHICLE message are supported

• PINGRX (not tested)
• TT-SC1 (tested)
• ADSBee1090 (tested)

TT-SC1 settings

• download software for ADSB TT-SC1 from https://www.aerobits.pl/product/aero/ , file Micro_ADSB_App-vX.XX.X_win_setup.zip and install it
• connect your ADSB to FC, connect both RX and TX pins
• in INAV configurator ports TAB set telemetry MAVLINK, and baudrate 115200
• go to CLI in inav configurator and set serialpassthrough for port you connected ADSB serialpassthrough [PORT_YOU_SELECTED - 1] 115200 rxtx and close configurator
• open ADSB program you installed, got to settings and set "telemetry" = MAVLINK,

PCB board for TT-SC1-B module https://oshwlab.com/error414/adsb-power-board

ADSBee 1090 settings

• connect to ADSBee1090 via USB and set COMMS_UART to mavlink2
  AT+PROTOCOL=COMMS_UART,MAVLINK2
AT+BAUDRATE=COMMS_UART,115200
  It's recommended to turn of wifi
  AT+ESP32_ENABLE=0
AT+SETTINGS=SAVE
• in INAV configurator ports TAB set telemetry MAVLINK, and baudrate 115200
• https://pantsforbirds.com/adsbee-1090/quick-start/

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Alert and Warning

The ADS-B warning/alert system supports two operating modes, controlled by the parameter adsb_calculation_use_cpa (ON or OFF).

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ADS-B Warning and Alert Messages (CPA Mode OFF)

The ADS-B warning/alert system supports two operating modes, controlled by the parameter adsb_calculation_use_cpa (ON or OFF).

When adsb_calculation_use_cpa = OFF, the system evaluates only the current distance between the aircraft and the UAV. The aircraft with the shortest distance is always selected for monitoring.

• If the aircraft enters the warning zone (adsb_distance_warning), the corresponding OSD element is displayed.
• If the aircraft enters the alert zone (adsb_distance_alert), the OSD element starts blinking, indicating a higher-priority alert.

This mode therefore provides a simple proximity-based warning determined purely by real-time distance.

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ADS-B Warning and Alert Messages (CPA Mode ON)

When adsb_calculation_use_cpa = ON, the system evaluates aircraft using the Closest Point of Approach (CPA) and predicted trajectories, not only the current distance.

1. Aircraft already inside the alert zone
   If one or more aircraft are currently inside the alert zone (adsb_distance_alert), the closest aircraft to the UAV is selected and the OSD element blinks.

2. Aircraft in the warning zone, none predicted to enter the alert zone
   If aircraft are present in the warning zone (adsb_distance_warning), but none of them are predicted to enter the alert zone (their CPA distance is greater than adsb_distance_alert), the closest aircraft to the UAV is selected and the OSD element remains steady (no blinking).

3. Aircraft in the warning zone, one predicted to enter the alert zone
   If at least one aircraft in the warning zone is predicted to enter the alert zone, that aircraft is selected and the OSD element blinks.

4. Aircraft in the warning zone, multiple predicted to enter the alert zone
   If multiple aircraft are predicted to enter the alert zone, the system selects the aircraft that will reach the alert zone first, and the OSD element blinks.