scholarly journals A Robust EMD-Based RVFL Network Fusion Algorithm for Low-Cost GPS/INS Integrated System

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Da Liu ◽  
Shufang Zhang ◽  
Jingbo Zhang
Keyword(s):  
Inertial Sensors ◽  
Low Cost ◽  
Integrated System ◽  
Fusion Algorithm ◽  
Functional Link ◽  
Mode Decomposition ◽  
Error Accumulation ◽  
Lower Complexity ◽  
High Level

Global positioning system (GPS) and inertial navigation system (INS) are commonly combined to overcome disadvantages of each and constitute an integrated system that realizes long-term precision. However, the performance of the integrated system deteriorates on which GPS is unavailable. Especially when low-cost inertial sensors based on the microelectromechanical system (MEMS) are used, performance of the integrated system degrades severely over time. In this study, in order to minimize the adverse impact of high-level stochastic noise from low-cost MEMS sensors, denoising technology based on empirical mode decomposition (EMD) is employed to improve signal quality before navigation solution by which significant improvement of removing noise is achieved. Moreover, a random vector functional link (RVFL) network-based fusion algorithm is presented to estimate and compensate position error during GPS outage such that error accumulation is suppressed quickly when INS is working standalone. Performance of the proposed approach is evaluated by experimental results. It is indicated from comparison that the proposed algorithm takes advantages such as better accuracy and lower complexity and is more robust than the commonly reported methods and is more appropriate for real-time and low-cost application.

CASE STUDY: STABILISATION OF A RAPIDLY ERODING POINT USING AN INSITU-FILLED GEOTEXTILE CONTAINER GROYNE FIELD

2017 ◽  
pp. 36
Author(s):  
Bobbie Corbett ◽  
Nicholas Wellwood ◽  
David Shing ◽  
Leslie Angus Jackson
Keyword(s):  
Low Cost ◽  
Low Risk ◽  
Recreational Beach ◽  
High Level

Munna Point is a premiere recreational beach in the Noosa River which has been maintained by regular nourishment for over 20 years. As longevity of each nourishment was less than 6 months, the long-term costs were high and efforts were eventually suspended resulting in loss of the beach. In an effort to reinstate the amenity and provide a more stable beach, a groyne field accompanied by nourishment was proposed. To provide a low-impact, low-risk and low-cost solution, the groynes were designed with a low crest using sand-filled geotextile containers. To achieve the design, containers and scour mattresses were filled in-situ using a dredge, which was an innovative application of a methodology typically adopted for much larger containers. The first 3 groynes have successfully been installed as part of the first stage and 12 months of monitoring subsequently undertaken. The groynes have clearly been effective at extending the longevity of the nourishment and the wider intertidal profile has remained very stable. The beach is now successfully enhancing the amenity of the community and experiencing a high level of usage.

scholarly journals An Accurate Heading Solution using MEMS-based Gyroscope and Magnetometer Integrated System (Preliminary Results)

2014 ◽  
Vol II-2 ◽  
pp. 75-78 ◽  
Author(s):  
M. El-Diasty
Keyword(s):  
Magnetic Field ◽  
Low Cost ◽  
Estimation Procedure ◽  
Integrated System ◽  
Static Mode ◽  
Earth Magnetic Field ◽  
Heading Estimation ◽  
High Level ◽  
Magnetic Disturbances ◽  
Over Time

An accurate heading solution is required for many applications and it can be achieved by high grade (high cost) gyroscopes (gyros) which may not be suitable for such applications. Micro-Electro Mechanical Systems-based (MEMS) is an emerging technology, which has the potential of providing heading solution using a low cost MEMS-based gyro. However, MEMS-gyro-based heading solution drifts significantly over time. The heading solution can also be estimated using MEMS-based magnetometer by measuring the horizontal components of the Earth magnetic field. The MEMS-magnetometer-based heading solution does not drift over time, but are contaminated by high level of noise and may be disturbed by the presence of magnetic field sources such as metal objects. This paper proposed an accurate heading estimation procedure based on the integration of MEMS-based gyro and magnetometer measurements that correct gyro and magnetometer measurements where gyro angular rates of changes are estimated using magnetometer measurements and then integrated with the measured gyro angular rates of changes with a robust filter to estimate the heading. The proposed integration solution is implemented using two data sets; one was conducted in static mode without magnetic disturbances and the second was conducted in kinematic mode with magnetic disturbances. The results showed that the proposed integrated heading solution provides accurate, smoothed and undisturbed solution when compared with magnetometerbased and gyro-based heading solutions.

scholarly journals Unsupervised Monocular Visual-inertial Odometry Network

2020 ◽  
Author(s):  
Peng Wei ◽  
Guoliang Hua ◽  
Weibo Huang ◽  
Fanyang Meng ◽  
Hong Liu
Keyword(s):  
Low Cost ◽  
Depth Map ◽  
Ground Truth ◽  
Optimization Strategy ◽  
Inherent Limitation ◽  
Geometric Consistency ◽  
Motion Features ◽  
Error Accumulation ◽  
Inertial Measurements

Recently, unsupervised methods for monocular visual odometry (VO), with no need for quantities of expensive labeled ground truth, have attracted much attention. However, these methods are inadequate for long-term odometry task, due to the inherent limitation of only using monocular visual data and the inability to handle the error accumulation problem. By utilizing supplemental low-cost inertial measurements, and exploiting the multi-view geometric constraint and sequential constraint, an unsupervised visual-inertial odometry framework (UnVIO) is proposed in this paper. Our method is able to predict the per-frame depth map, as well as extracting and self-adaptively fusing visual-inertial motion features from image-IMU stream to achieve long-term odometry task. A novel sliding window optimization strategy, which consists of an intra-window and an inter-window optimization, is introduced for overcoming the error accumulation and scale ambiguity problem. The intra-window optimization restrains the geometric inferences within the window through checking the photometric consistency. And the inter-window optimization checks the 3D geometric consistency and trajectory consistency among predictions of separate windows. Extensive experiments have been conducted on KITTI and Malaga datasets to demonstrate the superiority of UnVIO over other state-of-the-art VO / VIO methods. The codes are open-source.

scholarly journals CKF-Based Visual Inertial Odometry for Long-Term Trajectory Operations

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Trung Nguyen ◽  
George K. I. Mann ◽  
Andrew Vardy ◽  
Raymond G. Gosine
Keyword(s):  
Low Cost ◽  
Estimation Error ◽  
Optimization Procedure ◽  
Single Measurement ◽  
Cubature Kalman Filter ◽  
Graph Optimization ◽  
Error Accumulation ◽  
Entire Trajectory ◽  
Pose Graph Optimization

The estimation error accumulation in the conventional visual inertial odometry (VIO) generally forbids accurate long-term operations. Some advanced techniques such as global pose graph optimization and loop closure demand relatively high computation and processing time to execute the optimization procedure for the entire trajectory and may not be feasible to be implemented in a low-cost robotic platform. In an attempt to allow the VIO to operate for a longer duration without either using or generating a map, this paper develops iterated cubature Kalman filter for VIO application that performs multiple corrections on a single measurement to optimize the current filter state and covariance during the measurement update. The optimization process is terminated using the maximum likelihood estimate based criteria. For comparison, this paper also develops a second solution to integrate VIO estimation with ranging measurements. The wireless communications between the vehicle and multiple beacons produce the ranging measurements and help to bound the accumulative errors. Experiments utilize publicly available dataset for validation, and a rigorous comparison between the two solutions is presented to determine the application scenario of each solution.

scholarly journals Particle-Filter-Based WiFi-Aided Reduced Inertial Sensors Navigation System for Indoor and GPS-Denied Environments

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
M. M. Atia ◽  
M. J. Korenberg ◽  
A. Noureldin
Keyword(s):  
Particle Filter ◽  
Inertial Sensors ◽  
Low Cost ◽  
Indoor Navigation ◽  
Feature Reduction ◽  
Navigation Systems ◽  
Inertial Navigation Systems ◽  
Error Accumulation ◽  
Non Gaussian ◽  
Multipath Errors

Indoor navigation is challenging due to unavailability of satellites-based signals indoors. Inertial Navigation Systems (INSs) may be used as standalone navigation indoors. However, INS suffers from growing drifts without bounds due to error accumulation. On the other side, the IEEE 802.11 WLAN (WiFi) is widely adopted which prompted many researchers to use it to provide positioning indoors using fingerprinting. However, due to WiFi signal noise and multipath errors indoors, WiFi positioning is scattered and noisy. To benefit from both WiFi and inertial systems, in this paper, two major techniques are applied. First, a low-cost Reduced Inertial Sensors System (RISS) is integrated with WiFi to smooth the noisy scattered WiFi positioning and reduce RISS drifts. Second, a fast feature reduction technique is applied to fingerprinting to identify the WiFi access points with highest discrepancy power to be used for positioning. The RISS/WiFi system is implemented using a fast version of Mixture Particle Filter for state estimation as nonlinear non-Gaussian filtering algorithm. Real experiments showed that drifts of RISS are greatly reduced and the scattered noisy WiFi positioning is significantly smoothed. The proposed system provides smooth indoor positioning of 1 m accuracy 70% of the time outperforming each system individually.

scholarly journals MEMS Inertial Sensors Based Gait Analysis for Rehabilitation Assessment via Multi-Sensor Fusion

Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 442 ◽  
Author(s):  
Sen Qiu ◽  
Long Liu ◽  
Hongyu Zhao ◽  
Zhelong Wang ◽  
Yongmei Jiang
Keyword(s):  
Gait Analysis ◽  
Inertial Sensors ◽  
Low Cost ◽  
Calibration Method ◽  
Medical Rehabilitation ◽  
Sensor Data ◽  
Body Sensor Networks ◽  
Fusion Algorithm ◽  
Gait Impairments ◽  
Rehabilitation Assessment

Gait and posture are regular activities which are fully controlled by the sensorimotor cortex. In this study, fluctuations of joint angle and asymmetry of foot elevation in human walking stride records are analyzed to assess gait in healthy adults and patients affected with gait disorders. This paper aims to build a low-cost, intelligent and lightweight wearable gait analysis platform based on the emerging body sensor networks, which can be used for rehabilitation assessment of patients with gait impairments. A calibration method for accelerometer and magnetometer was proposed to deal with ubiquitous orthoronal error and magnetic disturbance. Proportional integral controller based complementary filter and error correction of gait parameters have been defined with a multi-sensor data fusion algorithm. The purpose of the current work is to investigate the effectiveness of obtained gait data in differentiating healthy subjects and patients with gait impairments. Preliminary clinical gait experiments results showed that the proposed system can be effective in auxiliary diagnosis and rehabilitation plan formulation compared to existing methods, which indicated that the proposed method has great potential as an auxiliary for medical rehabilitation assessment.

scholarly journals Focal Laser Ablation of Prostate Cancer: Definition, Needs, and Future

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Pierre Colin ◽  
Serge Mordon ◽  
Pierre Nevoux ◽  
Mohammed Feras Marqa ◽  
Adil Ouzzane ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Laser Ablation ◽  
Low Cost ◽  
Relevant Literature ◽  
Focal Therapy ◽  
Integrated System ◽  
Therapeutic Modality ◽  
Potential Candidate ◽  
Cancer Management

Current challenges and innovations in prostate cancer management concern the development of focal therapies that allow the treatment of only the cancer areas sparing the rest of the gland to minimize the potential morbidity. Among these techniques, focal laser ablation (FLA) appears as a potential candidate to reach the goal of focusing energy delivery on the identified targets. The aim of this study is to perform an up-to-date review of this new therapeutic modality. Relevant literature was identified using MEDLINE database with no language restrictions (entries: focal therapy, laser interstitial thermotherapy, prostate cancer, FLA) and by cross-referencing from previously identified studies. Precision, real-time monitoring, MRI compatibility, and low cost of integrated system are principal advantages of FLA. Feasibility and safety of this technique have been reported in phase I assays. FLA might eventually prove to be amiddle groundbetween active surveillance and radical treatment. In conclusion, FLA may have found a role in the management of prostate cancer. However, further trials are required to demonstrate the oncologic effectiveness in the long term.

scholarly journals Low-Cost MEMS-Based NARX Model for GPS-Denied Areas

2020 ◽  
pp. 58-70
Keyword(s):  
Inertial Sensors ◽  
Inertial Sensor ◽  
Low Cost ◽  
Autonomous Vehicle ◽  
Field Tests ◽  
Micro Electro Mechanical System ◽  
Integrated System ◽  
Main Challenge ◽  
Autonomous Vehicle Navigation ◽  
Narx Model

Autonomous vehicle navigation has witnessed a huge revolutionary revision regarding development in Micro-Electro Mechanical System (MEMS) technology. Most recently, Strapdown Inertial Navigation System (SDINS) has successfully been integrated with Global Positioning System (GPS). However, different grades of MEMS inertial sensors are available and choosing the convenient grade is quite important. Noises in inertial sensor are mostly treated through de-noising the additive errors to improve the precision of SDINS output. Unfortunately, integration in SDINS mechanization causes a growing in SDINS error output which considered the main challenge in integrating MEMS inertial sensors with GPS. This paper aims to promote the long-term performance of the MEMS-SDINS/GPS integrated system. A new integrated structure is proposed to model the nonlinearities that exist in SDINS dynamics in addition to the error uncertainty in the inertial sensors’ measurements. A robust Nonlinear AutoRegressive models with eXogenous inputs (NARX) based algorithm are designed for data fusion in the proposed GPS/INS integrated system. Validation for the proposed integrated system has been carried out using different field tests data in order to assess the accuracy of the system during GPS denied environment. The results obtained demonstrate that the proposed NARX model is applicative and satisfactory which shows a desired prediction performance.

scholarly journals Performance and Logistical Challenges of Alternative HIV-1 Virological Monitoring Options in a Clinical Setting of Harare, Zimbabwe

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Pascale Ondoa ◽  
Tinei Shamu ◽  
Michelle Bronze ◽  
Maureen Wellington ◽  
Tamara Sonia Boender ◽  
...  
Keyword(s):  
Virological Failure ◽  
Low Cost ◽  
Quality Care ◽  
Assay Sensitivity ◽  
Load Monitoring ◽  
Test Version ◽  
High Level ◽  
Virological Monitoring ◽  
Hiv 1

We evaluated a low-cost virological failure assay (VFA) on plasma and dried blood spot (DBS) specimens from HIV-1 infected patients attending an HIV clinic in Harare. The results were compared to the performance of the ultrasensitive heat-denatured p24 assay (p24). The COBAS AmpliPrep/COBAS TaqMan HIV-1 test, version 2.0, served as the gold standard. Using a cutoff of 5,000 copies/mL, the plasma VFA had a sensitivity of 94.5% and specificity of 92.7% and was largely superior to the VFA on DBS (sensitivity = 61.9%; specificity = 99.0%) or to the p24 (sensitivity = 54.3%; specificity = 82.3%) when tested on 302 HIV treated and untreated patients. However, among the 202 long-term ART-exposed patients, the sensitivity of the VFA decreased to 72.7% and to 35.7% using a threshold of 5,000 and 1,000 RNA copies/mL, respectively. We show that the VFA (either on plasma or on DBS) and the p24 are not reliable to monitor long-term treated, HIV-1 infected patients. Moreover, achieving acceptable assay sensitivity using DBS proved technically difficult in a less-experienced laboratory. Importantly, the high level of virological suppression (93%) indicated that quality care focused on treatment adherence limits virological failure even when PCR-based viral load monitoring is not available.

scholarly journals Integration of LTE 230 and LTE 1800 in Power Wireless Private Networks

2019 ◽  
Vol 11 (11) ◽  
pp. 221
Author(s):  
Ding ◽  
Miao ◽  
Zhang ◽  
Li ◽  
Liu ◽  
...  
Keyword(s):  
Mode Selection ◽  
Access Network ◽  
Integrated System ◽  
Core Network ◽  
Network Integration ◽  
Energy Internet ◽  
The Public ◽  
High Level ◽  
Private Network

Power wireless private networks (PWPNs) have been highly developed in China in recent years. They provide a basis for the energy Internet of Things, which enables the exchange of energy information between devices. Although the power wireless private network is an imitation of the public cellular network, a number of special challenges remain in power private networks. Due to the lack of general standards for PWPNs at the beginning of deployment, there are now two independent PWPN systems in China: long-term evolution (LTE) 230 and LTE 1800. Each has its own core and access networks with independent hardware. In this paper, we propose a high-level design of multinetwork integration to allow LTE 230 and LTE 1800 to coexist. For core network integration, we propose a protocol controller to select the active protocol according to the user’s mode selection, since both LTE 230 and LTE 1800 evolved from the standard LTE system. For access network integration, we propose a multinetwork integration controller to help the device access the optimal cell. The simulation results show that the integrated system can retain the advantages of these two independent systems in terms of both capacity and coverage.

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