Blade Control for Surface Profile Tracking by Heavy-Duty Bulldozers

2021 ◽  
Author(s):  
Teemu Mononen ◽  
Jouni Mattila ◽  
Antti Kolu
Keyword(s):  
High Performance ◽  
Surface Profile ◽  
Ground Surface ◽  
Satellite System ◽  
Mobile Manipulator ◽  
Heavy Duty ◽  
Hydraulic Actuator ◽  
Actual Surface ◽  
Global Navigation Satellite ◽  
Mobile Base

Abstract The bulldozer is a heavy-duty earthmoving machine used in ground surface profiling and soil manipulation. Tracking the desired surface gradients with the hydraulically actuated manipulator while compensating for the mobile base motion is important in high-performance surface grading and traction control. In this paper, we present an approach for surface elevation tracking control for earthmoving work done by bulldozers using inertial measurement units (IMUs) and roof mounted global navigation satellite system (GNSS) antennas. We use mapping between the desired surface profile and hydraulic actuator velocities using the elevation surface and its gradient, the mobile manipulator Jacobian, and mobile base pose estimation by the extended Kalman filter (EKF) framework. With the proposed method, a relatively simple low-level actuator space control scheme can produce sufficient accuracy in varying elevation requirements besides leveling work. In an experimental setup, flat and uneven surface profiles were followed with average errors below 2 cm computed using kinematics. An external GNSS survey gave a coarse verification of the actual surface profile, showing average errors below 4 cm. This paper demonstrates a blade controller on a heavy-duty tracked vehicle with high manipulator inertia, hydraulic dynamics, and body vibrations. The experimental results validate the efficacy of the proposed method, also revealing the needs for further development.

scholarly journals Deriving surface soil moisture from reflected GNSS signal observations from a grassland site in southwestern France

2017 ◽  
Author(s):  
Sibo Zhang ◽  
Jean-Christophe Calvet ◽  
José Darrozes ◽  
Nicolas Roussel ◽  
Frédéric Frappart ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Land Surface Model ◽  
Ground Surface ◽  
Satellite System ◽  
Surface Model ◽  
Global Navigation Satellite ◽  
Grassland Site

Abstract. This work aims to assess the estimation of surface volumetric soil moisture (VSM) using the Global Navigation Satellite System Interferometric Reflectometry (GNSS-IR) technique. Year-round observations were acquired from a grassland site in southwestern France using an antenna consecutively placed at two contrasting heights above the ground surface (3.3 or 29.4 m). The VSM retrievals are compared with two independent reference datasets: in situ observations of soil moisture, and numerical simulations of soil moisture and vegetation biomass from the ISBA (Interactions between Soil, Biosphere and Atmosphere) land surface model. Scaled VSM estimates can be retrieved throughout the year removing vegetation effects by the separation of growth and senescence periods and by the filtering of the GNSS-IR observations that are most affected by vegetation. Antenna height has no significant impact on the quality of VSM estimates. Comparisons between the VSM GNSS-IR retrievals and the in situ VSM observations at a depth of 5 cm show a good agreement (R2 = 0.86 and RMSE = 0.04 m3 m−3). It is shown that the signal is sensitive to the grass litter water content and that this effect triggers differences between VSM retrievals and in situ VSM observations at depths of 1 cm and 5 cm, especially during light rainfall events.

Quantifying the influence of low vegetation on vertical uncertainties of 3D point clouds derived from UAV-based ground surface measurements

2020 ◽  
Author(s):  
Sebastian Fischer ◽  
Anne Hormes ◽  
Marc S. Adams ◽  
Thomas Zieher ◽  
Magnus Bremer ◽  
...  
Keyword(s):  
Ground Surface ◽  
Surface Displacement ◽  
Point Clouds ◽  
Satellite System ◽  
Vegetation Height ◽  
3D Point Clouds ◽  
Dense Image ◽  
Multi Temporal ◽  
Surface Measurements ◽  
Global Navigation Satellite

<p>The use of unmanned aerial vehicles (UAV) for ground surface measurements in natural hazard studies has strongly increased in recent years. Multi-temporal 3D point clouds derived from light detection and ranging (LiDAR) sensors and photogrammetric techniques including structure-from-motion (SfM) and dense image matching (DIM) have become important tools for monitoring the activity of geomorphic processes. However, due to georeferencing errors and measurement inaccuracies, change detection with centimeter precision remains challenging, especially in study areas covered by vegetation. This study aims at quantifying the influence of low vegetation on the vertical uncertainties of 3D point clouds in a study area mostly covered by meadows and pastures with different grass heights. 3D point clouds derived from UAV-SfM and UAV-LiDAR are compared to terrestrial ground surface measurements of a differential global navigation satellite system (dGNSS) receiver in order to quantify the vertical uncertainties and to detect advantages/disadvantages of the different sensors. The results indicate that neither method is able to detect the ground surface under dense low vegetation with centimeter precision, and that surface displacement rates derived from multi temporal analyses can be highly influenced by changes in vegetation height between surveys.</p>

scholarly journals Seasonal and Interannual Ground-Surface Displacement in Intact and Disturbed Tundra along the Dalton Highway on the North Slope, Alaska

Land ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 22
Author(s):  
Go Iwahana ◽  
Robert C. Busey ◽  
Kazuyuki Saito
Keyword(s):  
Ground Surface ◽  
Surface Displacement ◽  
Satellite System ◽  
The North ◽  
Surface Displacements ◽  
Standard Deviation Range ◽  
Thaw Depth ◽  
Ice Wedge ◽  
Global Navigation Satellite ◽  
Northern Alaska

Spatiotemporal variation in ground-surface displacement caused by ground freeze–thaw and thermokarst is critical information to understand changes in the permafrost ecosystem. Measurement of ground displacement, especially in the disturbed ground underlain by ice-rich permafrost, is important to estimate the rate of permafrost and carbon loss. We conducted high-precision global navigation satellite system (GNSS) positioning surveys to measure the surface displacements of tundra in northern Alaska, together with maximum thaw depth (TD) and surface moisture measurements from 2017 to 2019. The measurements were performed along two to three 60–200 m transects per site with 1–5 m intervals at the three areas. The average seasonal thaw settlement (STS) at intact tundra sites ranged 5.8–14.3 cm with a standard deviation range of 2.1–3.3 cm. At the disturbed locations, averages and variations in STS and the maximum thaw depth were largest in all observed years and among all sites. The largest seasonal and interannual subsidence (44 and 56 cm/year, respectively) were recorded at points near troughs of degraded ice-wedge polygons or thermokarst lakes. Weak or moderate correlation between STS and TD found at the intact sites became obscure as the thermokarst disturbance progressed, leading to higher uncertainty in the prediction of TD from STS.

scholarly journals Deriving surface soil moisture from reflected GNSS signal observations from a grassland site in southwestern France

2018 ◽  
Vol 22 (3) ◽  
pp. 1931-1946 ◽  
Author(s):  
Sibo Zhang ◽  
Jean-Christophe Calvet ◽  
José Darrozes ◽  
Nicolas Roussel ◽  
Frédéric Frappart ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Land Surface Model ◽  
Ground Surface ◽  
Satellite System ◽  
Surface Model ◽  
Global Navigation Satellite ◽  
Grassland Site

Abstract. This work assesses the estimation of surface volumetric soil moisture (VSM) using the global navigation satellite system interferometric reflectometry (GNSS-IR) technique. Year-round observations were acquired from a grassland site in southwestern France using an antenna consecutively placed at two contrasting heights above the ground surface (3.3 and 29.4 m). The VSM retrievals are compared with two independent reference datasets: in situ observations of soil moisture, and numerical simulations of soil moisture and vegetation biomass from the ISBA (Interactions between Soil, Biosphere and Atmosphere) land surface model. Scaled VSM estimates can be retrieved throughout the year removing vegetation effects by the separation of growth and senescence periods and by the filtering of the GNSS-IR observations that are most affected by vegetation. Antenna height has no significant impact on the quality of VSM estimates. Comparisons between the VSM GNSS-IR retrievals and the in situ VSM observations at a depth of 5 cm show good agreement (R2= 0.86 and RMSE = 0.04 m3 m−3). It is shown that the signal is sensitive to the grass litter water content and that this effect triggers differences between VSM retrievals and in situ VSM observations at depths of 1 and 5 cm, especially during light rainfall events.

scholarly journals Application of Inertial and GNSS Integrated Navigation to Seabird Biologging

2021 ◽  
Vol 33 (3) ◽  
pp. 526-536
Author(s):  
Masaru Naruoka ◽  
Yusuke Goto ◽  
Henri Weimerskirch ◽  
Takashi Mukai ◽  
Taichi Sakamoto ◽  
...  
Keyword(s):  
Power Consumption ◽  
High Performance ◽  
Feasible Solution ◽  
Satellite System ◽  
Integrated Navigation ◽  
Guidance And Control ◽  
Marine Vehicles ◽  
Navigation Algorithm ◽  
Global Navigation Satellite ◽  
And Control

The study demonstrates the versatility of integration of inertial navigation and global navigation satellite system (GNSS) with its unique application to seabird biologging. Integrated navigation was originally developed in the field of aerospace engineering, which requires accurate and reliable position, velocity, and attitude information for the guidance and control of aircraft and spacecraft. Due to its high performance and recent progress of sensor development, integrated navigation has been widely used not only in aerospace but also in many fields represented by land and marine vehicles. One of its ultimate applications under the constraint on the size and power consumption of devices is this study. Seabird biologging involves attaching a logging device onto a seabird for scientific purposes to understand its biomechanics, behavior, and so on. Design restrictions for the device include several tens of grams mass, several tens of millimeters in length, and several tens of milliamperes of power consumption. It is more difficult to maintain the accuracy of such a device than applications to an artificial vehicle. This study has shown that integrated navigation is a feasible solution for such extreme applications with two examples: biologging for wandering albatrosses and great frigatebirds. Furthermore, it should be stressed that the navigation captured the world’s first data of their detailed trajectories and attitudes in their dynamic and thermal soarings. For completeness, the navigation algorithm, simulation results to show the effectiveness of the algorithm, and the logging devices attached to bird are also described.

scholarly journals A Fine-Tuned Positioning Algorithm for Space-Borne GNSS Timing Receivers

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2327 ◽  
Author(s):  
Xi Chen ◽  
QiHui Wei ◽  
YaFeng Zhan ◽  
TianYi Ma
Keyword(s):  
High Performance ◽  
Algorithm Design ◽  
Satellite System ◽  
Frequency Error ◽  
Satellite Position ◽  
Cubature Kalman Filter ◽  
Rms Error ◽  
Adverse Influence ◽  
Global Navigation Satellite ◽  
Positioning Algorithm

To maximize the usage of limited transmission power and wireless spectrum, more communication satellites are adopting precise space–ground beam-forming, which poses a rigorous positioning and timing requirement of the satellite. To fulfill this requirement, a space-borne global navigation satellite system (GNSS) timing receiver with a disciplined high-performance clock is preferable. The space-borne GNSS timing receiver moves with the satellite, in contrast to its stationary counterpart on ground, making it tricky in its positioning algorithm design. Despite abundant existing positioning algorithms, there is a lack of dedicated work that systematically describes the delicate aspects of a space-borne GNSS timing receiver. Based on the experimental work of the LING QIAO (NORAD ID:40136) communication satellite’s GNSS receiver, we propose a fine-tuned positioning algorithm for space-borne GNSS timing receivers. Specifically, the proposed algorithm includes: (1) a filtering architecture that separates the estimation of satellite position and velocity from other unknowns, which allows for a first estimation of satellite position and velocity incorporating any variation of orbit dynamics; (2) a two-threshold robust cubature Kalman filter to counteract the adverse influence of measurement outliers on positioning quality; (3) Reynolds averaging inspired clock and frequency error estimation. Hardware emulation test results show that the proposed algorithm has a performance with a 3D positioning RMS error of 1.2 m, 3D velocity RMS error of 0.02 m/s and a pulse per second (PPS) RMS error of 11.8ns. Simulations with MATLAB show that it can effectively detect and dispose outliers, and further on outperforms other algorithms in comparison.

scholarly journals Expressions for the Autocorrelation Function and Power Spectral Density of BOC Modulation Based on Convolution Operation

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jiangang Ma ◽  
Yikang Yang ◽  
Hengnian Li ◽  
Jisheng Li
Keyword(s):  
High Performance ◽  
Algorithm Design ◽  
Satellite System ◽  
Binary Offset Carrier ◽  
Simulation Performance ◽  
Convolution Operation ◽  
Power Spectral ◽  
Signal Simulation ◽  
The Fourier Transform ◽  
Global Navigation Satellite

We present universal expressions for the autocorrelation functions (ACFs) of the Binary Offset Carrier (BOC), Multiplexed BOC (MBOC), and Alternative BOC (AltBOC) modulations based on convolution operations. We also derive the expressions for the power spectrum densities (PSDs) of these modulations using the Fourier transform of their ACFs. The results obtained in this contribution are useful for Global Navigation Satellite System (GNSS) signal simulation, performance evaluation, and high-performance acquisition and tracking algorithm design. The derivation methods of the expressions for the ACFs are common and can be used to derive expressions for the ACFs of other BOC-based modulations.

Activity Tracking and Evaluation of Large-scale Collapse Zones using Synthetic Aperture Radar Differential Interferenc

2020 ◽  
Author(s):  
Jui Peng Wu ◽  
Chao Yuan Lin
Keyword(s):  
Synthetic Aperture Radar ◽  
Large Scale ◽  
Ground Surface ◽  
Vertical Displacement ◽  
Satellite System ◽  
Synthetic Aperture ◽  
Observation Instruments ◽  
Southern Taiwan ◽  
Global Navigation Satellite ◽  
Aperture Radar

<p>This study used synthetic aperture radar interference technology (InSAR) to monitor the activities of large-scale collapse zones in southern Taiwan (Tainan City, Kaohsiung City, Pingdong County). Large-scale collapse zones are widely distributed, in addition to the construction of observation instruments, how to use other telemetry technology to quickly obtain relevant change information as monitoring and early warning indicator is a vital issue. SAR images from southern Taiwan from 2015 to 2019 were analyzed to monitor the ground surface changes using synthetic aperture radar differential interference technology (DInSAR) and permanent scattering interferometry radar technology (PSInSAR), and were verified using global navigation satellite system measurements. DInSAR analysis shows that the vertical displacement of the surface is ±60mm, which is within the range of elevation tolerance error, so it is not possible to use the satellite tracking station to compare the trace displacement in large collapse areas. However, PsInSAR results show that if there is PS point in a large-scale collapse zone, the PS point may be used as index of stabilization, and once the PS point suddenly disappears, it is highly likely that the area will change, and special care should be taken.</p><p>Keywords: Interferometric SAR, large-scale collapse zones, PSInSAR</p><p> </p>

scholarly journals Modified WiFi-RSS Fingerprint Technique to locate Indoors-Smartphones: FENG building at Koya University as a case study

2017 ◽  
Vol 2 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Halgurd S. Maghdid ◽  
Ladeh Sardar Abdulrahman ◽  
Mohammed H. Ahmed ◽  
Azhin Tahir Sabir
Keyword(s):  
Global Positioning System ◽  
High Performance ◽  
Low Cost ◽  
Satellite System ◽  
Positioning System ◽  
Global Positioning ◽  
Accurate Position ◽  
Global Navigation Satellite ◽  
Gps System

Positioning system used for different purposes and different services, many researches are going on to find a more accurate position with low error within high performance. There are many localization solutions with different architectures, configurations, accuracies and reliabilities for both outdoors and indoors. For example, Global Navigation Satellite System (GNSS) technology has been used for outdoors.  Global Positioning System (GPS) is one of the most common outdoors tracking solutions in the world, for outdoors, however, when indoors; it could not be accurately tracked users by using a GPS system. This is because, when users enters into indoors the GPS signals will no longer available due to blocked by the roof of buildings and it is no longer considered as a viable option.  WiFi Positioning System (WPS) can be used as an alternative solution to define users’ position, especially when GPS signal is not available. Further, WPS is a low cost solution, because there is no need to deploying WiFi Access Points (WAPs) in the vicinity, as they are installed to access the Internet. In this paper, specifically, WiFi-RSS Fingerprinting technique is used to locate smartphones using WAPs signals with a modified calculation. The new modified calculation is to dynamic weighting of the WAPs RSS values based on the real-live indoors structure. The achieved positioning accuracy, based on several trial experiments, is up to 6 meters via the implemented algorithm in the MALTAB.

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