Hello,
I am currently using the Quectel L26-DR (ADR version, not UDR) and I would like to clarify its dead-reckoning capabilities.
Specifically, I want to know if the ADR version can operate properly and maintain reasonable accuracy when no external vehicle speed input (wheel-tick or CAN) is provided, relying solely on its internal IMU sensors and GNSS data.
In other words, is an external speed source mandatory for ADR to perform dead-reckoning, or can it function autonomously in such a configuration?
Hi,
Quectel’s documentation clearly distinguishes between ADR and UDR by stating, “L26-DR (ADR) requires vehicle speed input; L26-DR (UDR) does not.” If no external speed is available (speed + FWD/REV via wheel-tick or CAN/UART), the DR algorithm is not activated; only standard GNSS is used, and the IMU alone does not provide “reasonable” speed/DR accuracy.
The hardware/specification sheet also specifies a speed feed for ADR via Wheel Tick/UART/CAN; while there is support for “free-mounting,” this does not eliminate the need for speed information.
Quectel’s DR application notes and general descriptions reiterate that ADR, by design, requires speed (and possibly reverse gear) data from the vehicle. UDR, however, does not require this.
