A virtual reality headset that tracks motion of a user relative to a moving vehicle in which the user is located. The system updates the headset's display based on relative motion, rather than on absolute motion due to vehicle movement. Data from sensors on the headset, the vehicle, or both is analyzed to determine the pose (orientation, position, or both) of the headset relative to the vehicle. Sensors may include headset-mounted cameras that observe the vehicle's interior from the user's viewpoint. Analysis of camera images may use optical flow or it may compare images to reference images captured from known poses. The system may also combine data from headset sensors and vehicle sensors to calculate the relative pose. Headset-mounted cameras may function both as relative pose sensors for virtual reality, and as image capture devices for display of the real environment on the headset.