SETTINGS

Sampling

Sample interval Each accepted fix is one integration step. Many vehicles deliver at most about 1 fix per second, so faster settings may repeat the previous values.

Dead reckoning

Apply MAG VAR (WMM2025 declination) to the heading On: the reported heading is treated as magnetic and the local declination is added before integrating. Off: the heading is used as reported (true). Watch the HDG−COG pill while driving straight: if it reads about −MAG VAR the heading is magnetic and this should be on; if it reads about 0 the heading is already true. Heading lag compensation Use the heading reported k samples ago for each step. The calibration panel's lag analysis suggests a value after enough turns have been observed. Apply calibrated heading correction Apply calibrated speed correction Each correction can be switched off independently to see how much of the error it removes. Collection is unaffected. Show dead-reckoned trace (red) Show GPS trace (green)

Display

Speed units Error chart window Readout size Chart label size Pixels per inch Cybertruck 18.5″ ≈ 122 · Model 3/Y 15.4″ ≈ 147 · adjust until the bar below is 1 inch wide

1 inch

Font Theme Map orientation (while following) Basemap

CALIBRATION

Status

Apply heading correction Apply speed correction

Collection is manual. While it runs, every straight, accurate, moving step compares the GPS course and distance with the heading and speed the engine used. Corrections are applied automatically once a table has at least 20 samples, and they persist in this browser until cleared.

Heading vs GPS course

Rolling comparison of the reported heading with the course over ground, straight segments only. About 0° means the browser reports a true heading; about −MAG VAR means it reports a magnetic heading (turn MAG VAR on before calibrating so the calibration stays valid when you drive somewhere with a different declination).

Global corrections

Heading deviation table (16 sectors, by reported heading)

Sector	n	Bias (raw)	Bias (true)	MAD

Bias is added to the reported heading. "Raw" is used when MAG VAR is off, "true" (declination removed) when it is on. Rows with fewer than 20 samples are shown dimmed and fall back to the global value.

Speed scale table

Speed bin	n	Scale	MAD

Heading lag analysis

RMS heading error during turns when the heading is taken k samples back. Apply the best k in Settings → Heading lag compensation. Needs at least 100 turning steps per lag.

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