The ADS-B receiver's driver could not start

WarningRangefinder, optical flow, camera, OSD and other devices

What ArduPilot says:

ADSB: Unable to initialize ADSB driver
ADSB: Unable to initialize ADSB vehicle list

ADS-B is the radio system by which aircraft announce their position; with a receiver ArduPilot can show and avoid them. ADSB_TYPE is set, but no driver started (“Unable to initialize ADSB driver”), or there was no memory for the list of ADSB_LIST_MAX aircraft (“Unable to initialize ADSB vehicle list”). The aircraft flies, but sees no traffic. It does not try again until a reboot.

What to do, most likely first

The receiver speaks a serial protocol, and no port is set for it.
CheckADSB_TYPE 2, 3 and 4 (Sagetech, uAvionix UCP, Sagetech MX) need a port with SERIALn_PROTOCOL 35. Type 1 (uAvionix MAVLink, a pingRX) uses a MAVLink port instead.
FixSet SERIALn_PROTOCOL to 35 (ADSB) on the receiver's port and reboot.
No ADS-B receiver is fitted.
FixSet ADSB_TYPE to 0.
The firmware has no driver for that receiver, or memory is short.
CheckThe Firmware Inspector lists what a firmware file was built with.
FixBuild a firmware with the driver; if memory is the limit, lower ADSB_LIST_MAX or switch off features you do not use.

Parameters to look at

Parameter	What it is
`ADSB_TYPE`	ADSB Type
`ADSB_LIST_MAX`	ADSB vehicle list size
`SERIAL1_PROTOCOL`	Telem1 protocol selection
`SERIAL2_PROTOCOL`	Telemetry 2 protocol selection
`SERIAL3_PROTOCOL`	Serial 3 (GPS) protocol selection
`SERIAL4_PROTOCOL`	Serial4 protocol selection
`SERIAL5_PROTOCOL`	Serial5 protocol selection

Where to do it:Firmware Inspector Firmware Builder

The code that sends it

ADSB: Unable to initialize ADSB driver

libraries/AP_ADSB/AP_ADSB.cpp AP_ADSB::init() · Open in ArduPilot Copter-4.7.1

ADSB: Unable to initialize ADSB vehicle list

libraries/AP_ADSB/AP_ADSB.cpp AP_ADSB::init() · Open in ArduPilot Copter-4.7.1