Nonlinear Observer for Tightly Coupled Integration of Pseudorange and Inertial Measurements

2016 ◽  
Vol 24 (6) ◽  
pp. 2199-2206 ◽  
Author(s):  
Tor A. Johansen ◽  
Thor I. Fossen
Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3418 ◽  
Author(s):  
Junxiang Jiang ◽  
Xiaoji Niu ◽  
Ruonan Guo ◽  
Jingnan Liu

The fusion of visual and inertial measurements for motion tracking has become prevalent in the robotic community, due to its complementary sensing characteristics, low cost, and small space requirements. This fusion task is known as the vision-aided inertial navigation system problem. We present a novel hybrid sliding window optimizer to achieve information fusion for a tightly-coupled vision-aided inertial navigation system. It possesses the advantages of both the conditioning-based method and the prior-based method. A novel distributed marginalization method was also designed based on the multi-state constraints method with significant efficiency improvement over the traditional method. The performance of the proposed algorithm was evaluated with the publicly available EuRoC datasets and showed competitive results compared with existing algorithms.


2019 ◽  
Vol 27 (3) ◽  
pp. 1084-1099 ◽  
Author(s):  
Jakob M. Hansen ◽  
Tor Arne Johansen ◽  
Nadezda Sokolova ◽  
Thor I. Fossen

Robotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 23
Author(s):  
Bismaya Sahoo ◽  
Mohammad Biglarbegian ◽  
William Melek

In this paper, we present a novel method for visual-inertial odometry for land vehicles. Our technique is robust to unintended, but unavoidable bumps, encountered when an off-road land vehicle traverses over potholes, speed-bumps or general change in terrain. In contrast to tightly-coupled methods for visual-inertial odometry, we split the joint visual and inertial residuals into two separate steps and perform the inertial optimization after the direct-visual alignment step. We utilize all visual and geometric information encoded in a keyframe by including the inverse-depth variances in our optimization objective, making our method a direct approach. The primary contribution of our work is the use of epipolar constraints, computed from a direct-image alignment, to correct pose prediction obtained by integrating IMU measurements, while simultaneously building a semi-dense map of the environment in real-time. Through experiments, both indoor and outdoor, we show that our method is robust to sudden spikes in inertial measurements while achieving better accuracy than the state-of-the art direct, tightly-coupled visual-inertial fusion method.


Author(s):  
Kaori Kashimura ◽  
Takafumi Kawasaki Jr. ◽  
Nozomi Ikeya ◽  
Dave Randall

This chapter provides an ethnography of a complex scenario involving the construction of a power plant and, in so doing, tries to show the importance of a practice-based approach to the problem of technical and organizational change. The chapter reports on fieldwork conducted in a highly complex and tightly coupled environment: power plant construction. The ethnography describes work practices on three different sites and describes and analyses their interlocking dependencies, showing the difficulties encountered at each location and the way in which the delays that result cascade through the different sites. It goes on to describe some technological solutions that are associated with augmented reality and that are being designed in response to the insights gained from the fieldwork. The chapter also reflects more generally on the relationship between fieldwork and design in real-world contexts.


Author(s):  
Kelly Chance ◽  
Randall V. Martin

Blackbody radiation, temperature, and thermodynamic equilibrium give a tightly coupled description of systems (atmospheres, volumes, surfaces) that obey Boltzmann statistics. They provide descriptions of systems when Boltzmann statistics apply, either approximately or nearly exactly. These apply most of the time in the Earth’s stratosphere and troposphere, and in other planetary atmospheres as long as the density is sufficient that collisions among atmospheric molecules, rather than photochemical and photophysical properties, determine the energy populations of the ensemble of molecules. Thermodynamic equilibrium and the approximation of local thermodynamic equilibrium are introduced. Boltzmann statistics, blackbody radiation, and Planck’s law are described. The chapter introduces the Rayleigh-Jeans limit, description of noise sources as temperatures, Kirchoff’s law, the Stefan-Boltzmann constant, and Wien’s law.


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