In military aviation, head tracker technologies have become increasingly important to track the pilot's head position and
orientation, allowing the user to quickly interact with the operational environment. This technology allows the pilot to
quickly acquire items of interest and see Fighter Data Link type information. Acquiring the target on a helmet-mounted
tracker/display which can automatically slew a weapon's seeker is far more efficient than having to point at the target
with the nose of the aircraft as previously required for the heads-up display (HUD) type of target acquisition. The
United States Air Force (USAF) has used and evaluated a variety of helmet-mounted trackers for incorporation into their
high performance aircrafts. The Dynamic Tracker Test Fixture (DTTF) was designed by the Helmet-Mounted Sensory
Technology (HMST) laboratory to accurately measure rotation in one plane both static and dynamic conditions for the
purpose of evaluating the accuracy of head trackers, including magnetic, inertial, and optical trackers. This paper
describes the design, construction, capabilities, limitations, and performance of the DTTF.
The United States Air Force (USAF) uses and evaluates a variety of helmet-mounted trackers for incorporation into their
high performance aircraft. The primary head tracker technologies commercially available are magnetic trackers, inertial
trackers, and optical trackers. Each head tracker has a unique method of determining the pilot's head position within the
cockpit of the aircraft. Magnetic trackers generally have a small head mounted size and minimal head weight. Because
they sense a generated magnetic field, their accuracy can be affected by other magnetic fields or ferrous components
within the cockpit. Inertial trackers cover the entire head motion box but require constant motion in order to
accommodate drifting of the inertial sensors or a secondary system that updates the inertial system, often referred to as a
hybrid system. Although optical head trackers (OHT) are immune to magnetic fields some of their limitations may be
daylight/night vision goggle (NVG) compatibility issues and, depending on system configuration, may require numerous
emitters and/or receivers to cover a large head motion box and provide a wide field of regard. The Dynamic Tracker
Test Fixture (DTTF) was designed by the Helmet Mounted Sensory Technology (HMST) laboratory to accurately
measure azimuth rotation in both static and dynamic conditions for the purpose of determining the accuracy of a variety
of head trackers. Before the DTTF could be used as an evaluation tool, it required characterization to determine the
amount and location of any induced elevation or roll as the table rotated in azimuth. Optimally, the characterization
method would not affect the DTTF's movement so a non-contact method was devised. This paper describes the
characterization process and its results.
The Dynamic Tracker Test Apparatus (DTTA) was designed by the Helmet Mounted Sensory Technology (HMST)
laboratory to accurately measure azimuth rotation in both static and dynamic conditions. The DTTA was characterized
for static position data at various increments through a 360° sweep and for speeds up to 1000°/sec or 17.45 rad/sec. This
paper describes the design, construction, capabilities, limitations, characterization and performance of the DTTA.
Evaluating a system in flight poses challenges that are not found in a laboratory type environment. This paper discusses some of the issues in conducting an in-flight test to evaluate tracker accuracy,
such as head movement, synchronization of time, changing coordinate systems and interpolating data. The paper's technical approach outlines one possible solution to deal with in-flight challenges.
The Visually Coupled Acquisition Targeting System (VCATS) was initiated by the Air Force Research Laboratory (AFRL) and the Air Combat Command (ACC) to perform the risk reduction activities for developing a helmet-mounted tracker/display (HMT/D) in the air-to-air engagement arena. VCATS started as a one-year Operational Utility Evaluation (OUE) at Nellis Air Force Base (AFB), but expanded into a seven-year OUE, examining the human performance issues and the operational impacts of using an HMT/D for aircrews (See Figure 1). The VCATS system was designed and built with foresight and flexibility to allow upgrades more easily as technology and operational concepts evolved. This paper will trace this evolution of the VCATS system through initial design concept, system upgrades, technology transitions, and lessons learned.
In the last few years, airlines, commercial air carriers and the military have begun to introduce electronic tools into the cockpit to replace paper versions of flight publications, flight plans, departure and approach plates, maps, etc. These devices have varied from the common laptop to the smaller pen-tablet type computers. In some instances these devices have been connected to aircraft data buses to collect maintenance data, fault codes and other useful information. None of these devices, however, have been found satisfactory in ejection seat aircraft due to their size, weight, and dynamic characteristics when subjected to the inertial and aerodynamic forces that occur during an ejection. This paper describes an electronic digital kneeboard suitable for use in an ejection seat aircraft. The kneeboard consists of a look at helmet-mounted display, a small streamlined kneeboard input device, a carry-on/carry-off computer and its associated support interfaces.
This paper describes a method for evaluating helmet-mounted tracker accuracy installed in an aircraft sitting stationary on the ground. A test measurement test space is established by surveying numerous targets and ground control points with a laser surveying instrument. An aircraft is inserted arbitrarily into this test space and key points on the aircraft are surveyed along with the same ground control points originally surveyed. Mathematically, the two spaces are made to coincide at the ground control points, and then the entire space is transformed to place the aircraft so that the surveyed aircraft key points are located at their manufacture specified position. The helmet operator then looks at each target while other test operators record tracker output data. Data is subsequently analyzed.
The objective of this paper is to present an overview of the active matrix organic light emitting diode (OLED) microdisplay used in the integrated panoramic night vision goggle (IPNVG). These devices will be used to insert independent and overlaid video imagery into the IPNVG. Interface and operational details of the microdisplay relative to the IPNVG implementation in military aircraft will be discussed.
Modern fighter aircraft windscreens and canopies are typically made of curved, transparent plastic for improved aerodynamics and bird-strike protection. Since they are curved these transparencies often refract light in such a way that a pilot looking through the transparency will see a target in a location other than where it actually is. This effect has been known for many years and methods to correct the aircraft head-up display (HUD) for these angular deviations have been developed and employed. The same problem occurs for helmet-mounted displays (HMDs) used for target acquisition. However, for this application, correction of these errors is more difficult due to the fact the pilot can look through any part of the transparency instead of being constrained to just the forward section as in the case of the HUD. To determine the potential impact of these refractive errors on HMDs six F-15 windscreens and four F-15 canopies were measured from twelve different possible eye positions and a wide range of azimuth and elevation angles. These measurements were then used to develop 'best fit' curves that could be used to partially correct for the refractive effects of the transparencies.
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