TECHNICAL FIELD

The subject matter disclosed herein is directed generally to head-worn display (HWD) systems for aircraft pilots, and more particularly to alternative or backup systems for correcting drifting or misaligned headtracking systems.

BACKGROUND

Headtracking devices allow helmet-mounted or otherwise head-worn transparent display systems to provide pilots and crew of fightercraft or other aircraft with accurate enhanced vision (e.g., synthetic vision, augmented reality, mixed reality) by monitoring the position and orientation (“pose”) of the pilot's head relative to the aircraft with high accuracy, such that conformal information displayed to the pilot at any moment aligns precisely with what the pilot would otherwise be seeing when looking in that direction at that moment. Head misalignment errors may lead to misalignment of conformal critical flight information (e.g., conformal information displayed discontiguous with its actual location), with potentially catastrophic consequences.

SUMMARY

A high-assurance headtracking system for a head worn display (HWD) incorporating ground-truth fiducials is disclosed. In embodiments, the headtracking system includes a camera fixed to a mobile platform (e.g., an aircraft cockpit) and oriented toward a pilot wearing the HWD. Images captured by the camera detect fiducial markers attached to the HWD (and fixed in a device reference frame) and static fiducial markers fixed to the mobile platform, each static fiducial marker including a constellation of individual markers having a known position and orientation in the platform reference frame. The headtracking system include control processors for analyzing the images and identifying therein the device-frame and static fiducial markers. The headtracking system determines a device pose of the HWD relative to the platform reference frame and monitors the device pose for drift or error based on the known positions of the identified static fiducial markers.

In some embodiments, the device-frame fiducial markers and the platform-frame static fiducial markers include reflective markers or constellations thereof.

In some embodiments, the headtracking system refines the determined device pose based on the known positions of identified static fiducial markers (e.g., if the static fiducial markers indicate drift or error on the part of the device pose).

In some embodiments, the device-frame fiducial markers and the platform-frame static fiducial markers include light-emitting diodes (LED) or constellations thereof.

In some embodiments, the constellations of LEDs include constellations of individually addressable or programmable LEDs.

In some embodiments, the constellations of LEDs include pulse-width modulated (PWM) LEDs programmable by the headtracking system, e.g., at various brightness levels.

In some embodiments, the device-frame fiducial markers and the platform-frame static fiducial markers correspond to sets of unique encoded identifiers (e.g., constellation data or binary encoding).

In embodiments, the headtracking system encodes each constellation of markers (e.g., the device-frame fiducial markers and the platform-frame static fiducial markers) according to the sets of unique identifiers.

In embodiments, the unique encoded identifiers correspond to an orientation, or to a spatial extent, of a particular device-frame or platform-frame static fiducial marker, or to a marker constellation or subconstellation thereof.

In some embodiments, the headtracker system monitors the fixed alignment of the camera relative to the platform reference frame (in which it is fixed) based on the position and orientation information of identified platform-frame static fiducial markers within images captured by the camera.

This Summary is provided solely as an introduction to subject matter that is fully described in the Detailed Description and Drawings. The Summary should not be considered to describe essential features nor be used to determine the scope of the Claims. Moreover, it is to be understood that both the foregoing Summary and the following Detailed Description are example and explanatory only and are not necessarily restrictive of the subject matter claimed.

