GI Labs · Ego 1 GS VIO accuracy benchmark · September 2026

Stereo-inertial tracking vs. Vive Tracker

Under 1% drift per meter moved.

Two global-shutter cameras and an IMU are all Ego 1 GS needs to track its own motion. Across 7,545 one-meter movements its estimate drifts 0.87% on average, and after 8 meters of motion the error is still only 14 mm.

Vive Tracker reference Ego 1 GS VIO

t 0.0 sSession 5 · grid 10 cm · drag to rotate

Drag or use arrow keys to rotate the trajectory.

0.87%

Drift per meter

average of 7,545 one-meter movements

0.18%

Drift over 8 meters

14 mm after 8 m of motion

0.47°/m

Rotation drift per meter

falls to 0.10°/m over 8 m

0.21%

Drift over 30 seconds

14 mm across 6.1 m moved

Drift per movement

8 meters of motion, 14 mm of error

Error hardly grows as Ego 1 GS keeps moving: every stretch of motion from 0.25 m to 8 m, measured against the reference.

All sessionsEach session

Position error after the movement mm · mean

Drift as a share of distance moved % · mean

Rotation drift per meter °/m · mean

Every movement counted

96% of 2-meter movements drift under 1%

Not an average: the share of all movements in each drift band.

Movements by drift band all sessions

Drift per time

1.4 cm after 30 seconds of motion

Every time window from 0.1 s to 30 s, across all sessions. From 5 seconds on, drift stays under 1% of the distance moved.

All sessionsEach session

Position error in the window mm · RMSE

Drift as a share of distance moved %

Rotation error in the window ° · RMSE

Session 5 · 114 s

Steady from the first meter to the last

Drift over the meter just travelled, at every moment the device is moving.

Drift over the last 1 m %

All five sessions

Five sessions, five minutes, 60 meters

Same device, same calibration, every benchmark session shown.

ReferenceEgo 1 GS VIO

Drift per meter % · mean

Rotation drift per meter °/m · mean

Same recordings, same time window

Up to 46% less drift per meter than Basalt

Sessions 2–4 were also processed with Basalt, a widely used open-source VIO.

Ego 1 GS VIOBasalt

Drift per meter % · mean

Drift over 5 seconds mm · RMSE

Also measured

Absolute accuracy

Position against the reference after one alignment in the first 5 seconds, never repeated.

Vive Tracker referenceEgo 1 GS VIO

Session 5 RMSE 10.4 mm · 0.66° All sessions RMSE 14.7 mm · 0.73° Poses within 2 cm 86%

Top view session 5 · grid 10 cm

Side view grid 10 cm

Close-up

Position error over time session 5 · mm

Position RMSE by session mm

Share of poses within an error all sessions

Results

Every number, per session

			Drift per movement			Drift per time		Absolute
Session	Duration	Distance	Per 1 m	Per 2 m	Rotation / 1 m	Over 1 s	Over 5 s	Position RMSE	Orientation RMSE
Session 1	41.6 s	10.4 m	0.85%	0.45%	0.47°/m	7.0 mm	8.8 mm	9.4 mm	0.67°
Session 2	39.7 s	9.3 m	0.92%	0.57%	0.38°/m	7.0 mm	9.5 mm	12.2 mm	0.52°
Session 3	54.5 s	11.1 m	1.32%	0.70%	0.52°/m	8.7 mm	14.3 mm	24.0 mm	0.72°
Session 4	51.2 s	10.0 m	0.73%	0.49%	0.46°/m	6.0 mm	7.4 mm	14.9 mm	1.02°
Session 5	113.9 s	18.9 m	0.67%	0.40%	0.48°/m	4.8 mm	8.0 mm	10.4 mm	0.66°
All sessions	300.9 s	59.7 m	0.87%	0.51%	0.47°/m	6.5 mm	9.6 mm	14.7 mm	0.73°

Method

How we measured

Ego 1 GS2 global-shutter cameras + IMU

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VIO trajectory6-DoF pose, 30 Hz

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Pose-by-pose comparison100% of VIO poses matched to the reference

Vive TrackerRigidly mounted on Ego 1 GS

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Reference trajectory6-DoF pose, 120 Hz

Drift per movementFor every stretch of motion of a set length, the motion Ego 1 GS measured is compared with the reference. The gap, divided by the distance, is the drift.

Drift per timeThe same comparison over every time window from 0.1 s to 30 s. No alignment is involved.

Absolute errorOne rigid alignment over the first 5 seconds, then never repeated. No scale fitting — distances are true metric.

Stereo-inertial VIOOpenVINS-based pipeline, run on the camera and IMU streams Ego 1 GS records.

Everything countedReported error also contains the Vive Tracker's own error and calibration and time-sync uncertainty.