Integration of radar altimeter, precision navigation, and digital terrain data for low-altitude flight

Zelenka, Richard E.

doi:10.2514/6.1992-4420

“…TRN is also used to augment other sensor systems, for example to suppress false alarms in ground proximity warning systems (GPWS) or to improve the confidence in GPWS algorithms or to identify GPS failure modes. TRN systems are also combined with radar altimeter systems to confirm database integrity by matching altimeter returns with terrain profiles' 25 '.…”

Section: Terrain Reference Navigation (Trn)mentioning

confidence: 99%

Avionics, systems design and simulation

Allerton¹

1996

Aeronaut. j.

3

0

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The paper reviews the developments in avionics over the last seventy years, focusing on the impact of computer technology during the last ten years. The development of aircraft navigation systems is described, including present day satellite navigation and terrain reference navigation. The techniques used in aircraft displays are outlined including CRTs and LCDs and covering head up displays, helmet mounted displays and synthetic displays. The systems architecture which forms the basis of modem avionics is described, covering the major aircraft databuses in use including recent developments in integrated modular avionics. Developments in real-time software, which has become a major cost in many programmes, are covered, leading to the techniques used to ensure aircraft reliability, particularly fault tolerant architectures and also safety systems for health monitoring and recent research in ‘pilot associates'. The paper also summarises developments in flight control systems for both civil and military aircraft. The paper concludes with a brief review of future developments in avionics, speculating on the role of pilot in future aircraft.

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“…TRN is a navigation technology that estimates the aircraft's precise position by comparing the altitude measured by an altimeter with the loaded digital elevation model (DEM) [8,9]. Existing TRN techniques use a radio altimeter to measure the distance between the ground level and the aircraft [10]. If a radio altimeter (RA) is used at a low altitude, a precise altitude measurement can be obtained because the radio wave reflection area is narrow, but if the altitude is higher than 800 m, the radio wave reflection area is wide, which increases the uncertainty of the reflected location of the wave and errors in the measured altitude increase.…”

Section: Introductionmentioning

confidence: 99%

A Pragmatic Approach to the Design of Advanced Precision Terrain-Aided Navigation for UAVs and Its Verification

Lee

¹

,

Sung

²

,

Oh

³

et al. 2020

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Autonomous unmanned aerial vehicles (UAVs) require highly reliable navigation information. Generally, navigation systems with the inertial navigation system (INS) and global navigation satellite system (GNSS) have been widely used. However, the GNSS is vulnerable to jamming and spoofing. The terrain referenced navigation (TRN) technique can be used to solve this problem. In this study, to obtain reliable navigation information even if a GNSS is not available or the degree of terrain roughness is not determined, we propose a federated filter based INS/GNSS/TRN integrated navigation system. We also introduce a TRN system that combines batch processing and an auxiliary particle filter to ensure stable flight of UAVs even in a long-term GNSS-denied environment. As an altimeter sensor for the TRN system, an interferometric radar altimeter (IRA) is used to obtain reliable navigation accuracy in high altitude flight. In addition, a parallel computing technique with general purpose computing on graphics processing units (GPGPU) is applied to process a high resolution terrain database and a nonlinear filter in real-time on board. Finally, the performance of the proposed system is verified through software-in-the-loop (SIL) tests and captive flight tests in a GNSS unavailable environment.

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“…TRN is a navigation technology that estimates the aircraft's precise position by comparing the altitude measured by an altimeter with the loaded digital elevation model (DEM) [8], [9]. Existing TRN techniques use a radio altimeter to measure the distance between the ground level and the aircraft [10]. If a radio altimeter (RA) is used at a low altitude, a precise altitude measurement can be obtained because the radio wave reflection area is narrow, but if the altitude is higher than 800m, the radio wave reflection area is wide, and that increases the uncertainty of the reflected location of the wave, and errors in the measured altitude increase.…”

Section: Introductionmentioning

confidence: 99%

A Pragmatic Approach to the Design of Advanced Precision Terrain Aided Navigation for UAVs and Its Verification

Lee¹,

Sung²,

Oh³

et al. 2020

Preprint

1

0

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Autonomous unmanned aerial vehicles (UAVs) require highly reliable navigation information. Generally, navigation systems with the inertial navigation system (INS) and global navigation satellite system (GNSS) have been widely used. However, the GNSS is vulnerable to jamming and spoofing. The terrain referenced navigation (TRN) technique can be used to solve this problem. In this study, to obtain reliable navigation information even if a GNSS is not available or the degree of terrain roughness is not determined, we propose a federated filter based INS/GNSS/TRN integrated navigation system. we also introduce a TRN system that combines batch processing and an auxiliary particle filter to ensure stable flight of UAVs even in a long-term GNSS-denied environment. As an altimeter sensor for the TRN system, we use an interferometric radar altimeter (IRA) to obtain reliable navigation accuracy in high altitude flight. In addition, a parallel computing technique with general-purpose computing on graphics processing units (GPGPU) is applied to process a high resolution terrain database and a nonlinear filter in real time on board. Finally, we verify the performance of the proposed system through software-in-the-loop (SIL) tests and captive flight tests in a GNSS unavailable environment.

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Integration of radar altimeter, precision navigation, and digital terrain data for low-altitude flight

Cited by 8 publications

References 3 publications

Avionics, systems design and simulation

Avionics, systems design and simulation

A Pragmatic Approach to the Design of Advanced Precision Terrain-Aided Navigation for UAVs and Its Verification

A Pragmatic Approach to the Design of Advanced Precision Terrain Aided Navigation for UAVs and Its Verification

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