Practical answer

Dual-band reception can reduce some ionospheric error and improve resilience, but it does not guarantee centimetre accuracy. Verify the chosen lap-timing app, permissions, recorded rate and export before track use.

What to verify before track use

Position
Delivered and recorded update rate, fix quality and timestamp basis
Motion
Which sensors are exposed, axes, rate and raw versus fused values
Files
CSV, VBO, GPX, FIT, video metadata or proprietary session
Reliability
Background recording, heat, power, storage and interruptions
Do not infer a fixed GPS rate.

No fixed motorsport logging rate is claimed unless the device and app documentation explicitly provide it.

Phone + external GNSS

Improve position recording.

Phone + OBD-II

Add vehicle channels.

Primary sources