The Three-Dimensional Landing Zone (3D-LZ) Joint Capability Technology Demonstration (JCTD) is a 27-month program to develop an integrated LADAR and FLIR capability upgrade for USAF Combat Search and Rescue HH-60G Pave Hawk helicopters through a retrofit of current Raytheon AN/AAQ-29 turret systems. The 3D-LZ JCTD builds upon a history of technology programs using high-resolution, imaging LADAR to address rotorcraft cruise, approach to landing, landing, and take-off in degraded visual environments with emphasis on brownout, cable warning and obstacle avoidance, and avoidance of controlled flight into terrain. This paper summarizes ladar development, flight test milestones, and plans for a final flight test demonstration and Military Utility Assessment in 2014.
A joint-service team led by the Air Force Research Laboratory's Munitions and Sensors Directorates completed a
successful flight test demonstration of the 3D-LZ Helicopter LADAR Imaging System. This was a milestone
demonstration in the development of technology solutions for a problem known as "helicopter brownout", the loss of
situational awareness caused by swirling sand during approach and landing. The 3D-LZ LADAR was developed by
H.N. Burns Engineering and integrated with the US Army Aeroflightdynamics Directorate's Brown-Out Symbology
System aircraft state symbology aboard a US Army EH-60 Black Hawk helicopter. The combination of these systems
provided an integrated degraded visual environment landing solution with landing zone situational awareness as well as
aircraft guidance and obstacle avoidance information. Pilots from the U.S. Army, Air Force, Navy, and Marine Corps
achieved a 77% landing rate in full brownout conditions at a test range at Yuma Proving Ground, Arizona. This paper
will focus on the LADAR technology used in 3D-LZ and the results of this milestone demonstration.
Two topics are discussed in this paper. The first is the Integrated Multi-sensor Synthetic Imagery System
(IMSIS), being developed under an Army SBIR contract. The system updates on-board, pre-stored, terrain
elevation data with 3D terrain elevation sensor data (such as radar). The system also merges 2D image
contrast sensor data (such as infrared imagery) with the updated 3D terrain elevation data to render a
synthetic image of the terrain on the rotorcraft pilot's display. The second topic is the testing of a new flight
path marker, to show the pilot the predicted location of the aircraft with respect to the synthetic terrain (at
100m distance), as well as the predicted height above the terrain, the desired height above the terrain, and the
point on the terrain the aircraft is expected to fly over. The Altitude and ground Track Predicting Flight Path
Marker (ATP-FPM) symbol takes advantage of knowledge of terrain elevations ahead of the aircraft from a
synthetic vision system, such as IMSIS. In simulation, the maximum low altitude error and maximum ground
track error were both reduced by a factor of 2 with the ATP-FPM compared to the traditional instantaneous
flight path marker. Pilot-to-pilot variations in performance were reduced and workload decreased with the
ATP-FPM.
A series of studies was conducted to improve the Army aviator's ability to perform night missions by developing innovative symbols that capitalize on the advantages of new wide field-of-view (WFOV) helmet-mounted displays (HMDs). The most important outcomes of the research were two new symbol types called the Cylinder and the Flight Path Predictor. The Cylinder provides a large symbolic representation of real-world orientation that enables pilots to maintain the world frame of reference even if the visibility of the world is lost due to dust, smoke, snow, or inadvertent instrument meteorological conditions (IMC). Furthermore, the Cylinder is peripherally presented, supporting the “ambient” visual mode so that it does not require the conscious attention of the viewer. The Flight Path Predictor was developed to show the predicted flight path of a maneuvering aircraft using earth-referenced HMD symbology. The experimental evidence and the pilot interview results show that the new HMD symbology sets are capable of preventing spatial disorientation, improving flight safety, enhancing flight maneuver precision, and reducing workload so that the pilot can more effectively perform the critical mission tasks.
The U.S. Army Aviation mission includes flying helicopters at low altitude, at night, and in adverse weather. Night Vision Devices (NVDs) are used to supplement the pilot's visual cues for night flying. As the military requirement to conduct night helicopter operations has increased, the impact of helicopter flight operations with NVD technology in the Degraded Visual Environment (DVE) became increasingly important to quantify. Aeronautical Design Standard-33 (ADS- 33) was introduced to update rotorcraft handling qualities requirements and to quantify the impact of the NVDs in the DVE. As reported in this paper, flight test methodology in ADS-33 has been used by the handling qualities community to measure the impact of NVDs on task performance in the DVE. This paper provides the background and rationale behind the development of ADS-33 flight test methodology for handling qualities in the DVE, as well as the test methodology developed for human factor assessment of NVDs in the DVE. Lessons learned, shortcomings and recommendations for NVD flight test methodology are provided in this paper.
The effect of night vision devices and degraded visual imagery on self-attitude perception is unknown. Thirteen Army aviators with normal vision flew five flights under various visual conditions in a modified AH-1 (Cobra) helicopter. Subjects estimated their altitude or flew to specified altitudes while flying a series of maneuvers. The results showed that subjects were better at detecting and controlling changes in altitude than they were at flying to or naming a specific altitude. In cruise flight and descent, the subjects tended to fly above the desired altitude, an error in the safe direction. While hovering, the direction of error was less predictable. In the low-level cruise flight scenario tested in this study, altitude perception was affected more by changes in image resolution than by changes in FOV or ocularity.
The work reported in this paper examines the effect of restricting visual field-of-view (FOV) on rotorcraft pilot head movement. To simulate the FOVs of current and future helmet mounted displays (HMDs) used for night vision pilotage, a FOV restrictor was attached to the helmets of the test subject pilots. The restrictor limited horizontal FOV to 100, 80, 60, 40, and 20 degrees. Ten test subject pilots executed a set of low altitude flight maneuvers in an instrumented NAH-1S helicopter at the NASA Crows' Landing Airfield Head movement was measured with an IR head tracker for those pilots who flew in the rear seat and by a video camera for those who flew in the front seat. Test data indicated that pilots responded to restriction sin horizontal FOV by changing their pattern of head movement, both in azimuth and elevation. These compensation strategies change as FOV decreases and vary from pilot to pilot. Test results reported in this paper, in conjunction with referenced data outlining FOV effects on flight performance, handling qualities, and visual cue ratings, give visionic system designers and users predictive information on pilot workload and performance.
The Aeroflightdynamics Directorate of the US Army's Aviation Research, Development and Engineering Center initiated a study to determine the effects of limiting a rotorcraft pilot's field-of-view (FOV) on performance and workload. Pilot FOV was restricted to simulate current and next generation helmet mounted display FOVs used in night vision systems. A helmet visor was constructed for this test to restrict the horizontal peripheral limits of the square shaped FOV to values of 100, 80, 60, 40, and 20 degrees. The vertical limits and overlap were held constant to 40 degrees (except for the 20 degree FOV). Six pilots executed a series of prescribed low altitude maneuvers with an instrumented NAH-IS (Cobra) rotorcraft at the Crows Landing Airfield located in California. The aircraft flight path was measured with a laser tracker. On board data was recorded, as well as pilot handling quality ratings and visual cue ratings. This test is not yet complete, but some preliminary observations and results are provided. It was observed that reducing FOV increased the difficulty of controlling the aircraft and altered head movement. Reducing FOV also diminished the pilots' situational awareness. The reduction in situational awareness affected the ability of the pilots to provide an accurate report of their own flying performance, and the ability to observe warning indicators inside the cockpit.
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