RaceChrono logs

• File type: CSV v3 session exports from the RaceChrono / RaceChrono Pro lap-timing app (Android/iOS)
• Supported devices: Any session recorded in RaceChrono — phone GPS or external GPS receivers, phone accelerometer/gyroscope/magnetometer, and OBD-II / CAN-Bus channels from a connected adapter
• Features: All sources merged on one time axis, duplicate channel names disambiguated by source, multi-fragment (paused and resumed) sessions, GPS Track Map support out of the box

Supported File Format

RaceChrono CSV v3 files start with a banner and a metadata preamble, followed by a header row, a units row, and a sources row:

This file is created using RaceChrono Pro v10.1.3 ( http://racechrono.com/ ).
Format,3
Session title,"My Track Session"
Session type,Lap timing
...

timestamp,fragment_id,lap_number,elapsed_time,...,latitude,longitude,...,speed,...,rpm
unix time,,,s,...,deg,deg,...,m/s,...,rpm
,,,,...,100: gps,100: gps,...,calc,...,300: canbus
1785849363.002,0,,0.002,...,44.831825,11.224415,...,0.0,...,850.0

How to Export from RaceChrono

1. Open the session in RaceChrono
2. Tap the share/export button and choose CSV v3 as the export format
3. Load the resulting .csv file directly into UltraLog

Only CSV v3 is supported. The other RaceChrono export formats (.vbo, .rcz, CSV v1/v2) will not load — UltraLog shows a clear error asking for a CSV v3 re-export if it sees an older CSV version.

Supported Data

• GPS: latitude, longitude, altitude, speed, bearing, accuracy, satellites, fix type
• Phone sensors: accelerometer (x/y/z), gyroscope, magnetometer, and derived lateral/longitudinal/combined acceleration and lean angle
• Lap timing: lap number, fragment id, distance traveled
• OBD-II / CAN: every channel the session logged (RPM, engine oil temp, throttle, and more)

Channel Naming

RaceChrono exports the same column name once per source (for example speed from GPS and from the calculated pipeline). UltraLog disambiguates duplicates with the source label — speed (gps), speed (calc), device_update_rate (acc) — while unique names such as latitude, longitude, and rpm are kept exactly as exported.

Timestamp Handling

The timestamp column is unix time. UltraLog re-bases it so the first record is t = 0. The elapsed_time column resets to zero at every fragment boundary (each time the recording was paused and resumed), so it is kept as a regular channel rather than used as the time axis.

GPS Track Map

Because latitude/longitude arrive in decimal degrees under their standard names, the GPS Track Map works immediately: lap detection, channel-colored track polyline, and cursor sync.