scholarly journals UAV-LiCAM SYSTEM DEVELOPMENT: CALIBRATION AND GEO-REFERENCING

2018 ◽  
Vol XLII-1 ◽  
pp. 107-114 ◽  
Author(s):  
C. Cortes ◽  
M. Shahbazi ◽  
P. Ménard
Keyword(s):  
Particle Filtering ◽  
System Development ◽  
Low Cost ◽  
Base Station ◽  
Dual Frequency ◽  
Body Frame ◽  
Integrated Sensor ◽  
Sensor Orientation ◽  
Wide Range ◽  
Gnss Measurements

<p><strong>Abstract.</strong> In the last decade, applications of unmanned aerial vehicles (UAVs), as remote-sensing platforms, have extensively been investigated for fine-scale mapping, modeling and monitoring of the environment. In few recent years, integration of 3D laser scanners and cameras onboard UAVs has also received considerable attention as these two sensors provide complementary spatial/spectral information of the environment. Since lidar performs range and bearing measurements in its body-frame, precise GNSS/INS data are required to directly geo-reference the lidar measurements in an object-fixed coordinate system. However, such data comes at the price of tactical-grade inertial navigation sensors enabled with dual-frequency RTK-GNSS receivers, which also necessitates having access to a base station and proper post-processing software. Therefore, such UAV systems equipped with lidar and camera (UAV-LiCam Systems) are too expensive to be accessible to a wide range of users. Hence, new solutions must be developed to eliminate the need for costly navigation sensors. In this paper, a two-fold solution is proposed based on an in-house developed, low-cost system: 1) a multi-sensor self-calibration approach for calibrating the Li-Cam system based on planar and cylindrical multi-directional features; 2) an integrated sensor orientation method for georeferencing based on unscented particle filtering which compensates for time-variant IMU errors and eliminates the need for GNSS measurements.</p>

scholarly journals PERFORMANCE ASSESSMENT OF INTEGRATED SENSOR ORIENTATION WITH A LOW-COST GNSS RECEIVER

2017 ◽  
Vol IV-2/W3 ◽  
pp. 75-80 ◽  
Author(s):  
M. Rehak ◽  
J. Skaloud
Keyword(s):  
Position Control ◽  
Low Cost ◽  
Satellite System ◽  
Bundle Adjustment ◽  
Single Frequency ◽  
Reference Trajectory ◽  
Integrated Sensor ◽  
Homogeneous Surface ◽  
Gnss Receiver ◽  
Sensor Orientation

Mapping with Micro Aerial Vehicles (MAVs whose weight does not exceed 5&amp;thinsp;kg) is gaining importance in applications such as corridor mapping, road and pipeline inspections, or mapping of large areas with homogeneous surface structure, e.g. forest or agricultural fields. In these challenging scenarios, integrated sensor orientation (ISO) improves effectiveness and accuracy. Furthermore, in block geometry configurations, this mode of operation allows mapping without ground control points (GCPs). Accurate camera positions are traditionally determined by carrier-phase GNSS (Global Navigation Satellite System) positioning. However, such mode of positioning has strong requirements on receiver’s and antenna’s performance. In this article, we present a mapping project in which we employ a single-frequency, low-cost (<&amp;thinsp;$100) GNSS receiver on a MAV. The performance of the low-cost receiver is assessed by comparing its trajectory with a reference trajectory obtained by a survey-grade, multi-frequency GNSS receiver. In addition, the camera positions derived from these two trajectories are used as observations in bundle adjustment (BA) projects and mapping accuracy is evaluated at check points (ChP). Several BA scenarios are considered with absolute and relative aerial position control. Additionally, the presented experiments show the possibility of BA to determine a camera-antenna spatial offset, so-called lever-arm.

Advantages and risks of crowdfunding as a model of financing startups and community development projects

2021 ◽  
Vol 2021 (4) ◽  
pp. 84-98
Author(s):  
Vitalii RYSIN ◽  
Keyword(s):  
Community Development ◽  
System Development ◽  
Low Cost ◽  
Public Awareness ◽  
Development Projects ◽  
The Public ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
Capital Access

Crowdfunding as a tool for alternative financing has emerged relatively recently and is of limited use in Ukraine today. At the same time, it has significant potential, which can contribute to the implementation of a wide range of projects that for various reasons are not of interest to traditional lenders or investors. The aim of the article is to determine the benefits of crowdfunding for its participants, the peculiarities of the implementation of certain types of crowdfunding and identify risks that may be generated by them, as well as develop practical recommendations for crowdfunding campaigns by entrepreneurs and authors of community development projects. The article identifies the benefits of crowdfunding for project authors (low cost of capital, access to information and potential investors) and investors (clarity, low risks, access to new products, the ability to support creative ideas), substantiates the role of crowdfunding platforms in realizing the benefits of crowdfunding. The advantages and disadvantages of using certain types of crowdfunding are described. Recommendations for planning and implementation of the main stages of crowdfunding campaigns - idea development, target audience determination, research, communication, project budgeting, reward system development, campaign schedule development – are developed. The factors of choosing a crowdfunding platform for hosting the project are determined. The possibility of using crowdfunding for collective financing of socio-cultural projects within the public budgets of the united territorial communities is shown. The risks of using crowdfunding for project authors and potential investors are identified. Those risks are primarily related to realistic expectations and proper preparation for the fundraising campaign by project authors, as well as the lack of guarantees for investors in the event of problems or bankruptcy of the crowdfunding platform. The author highlights that the growth of public awareness about the possibilities of implementing social or business initiatives through crowdfunding platforms will contribute to the development of platforms, improvement of technological equipment, and expansion of their range of services.

scholarly journals Feasibility of Using Low-Cost Dual-Frequency GNSS Receivers for Land Surveying

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1956
Author(s):  
Natalia Wielgocka ◽  
Tomasz Hadas ◽  
Adrian Kaczmarek ◽  
Grzegorz Marut
Keyword(s):  
Real Time ◽  
Field Experiments ◽  
Low Cost ◽  
Base Station ◽  
Global Navigation Satellite Systems ◽  
Single Frequency ◽  
Signal Acquisition ◽  
Dual Frequency ◽  
Static Mode ◽  
Land Surveying

Global Navigation Satellite Systems (GNSS) have revolutionized land surveying, by determining position coordinates with centimeter-level accuracy in real-time or up to sub-millimeter accuracy in post-processing solutions. Although low-cost single-frequency receivers do not meet the accuracy requirements of many surveying applications, multi-frequency hardware is expected to overcome the major issues. Therefore, this paper is aimed at investigating the performance of a u-blox ZED-F9P receiver, connected to a u-blox ANN-MB-00-00 antenna, during multiple field experiments. Satisfactory signal acquisition was noticed but it resulted as >7 dB Hz weaker than with a geodetic-grade receiver, especially for low-elevation mask signals. In the static mode, the ambiguity fixing rate reaches 80%, and a horizontal accuracy of few centimeters was achieved during an hour-long session. Similar accuracy was achieved with the Precise Point Positioning (PPP) if a session is extended to at least 2.5 h. Real-Time Kinematic (RTK) and Network RTK measurements achieved a horizontal accuracy better than 5 cm and a sub-decimeter vertical accuracy. If a base station constituted by a low-cost receiver is used, the horizontal accuracy degrades by a factor of two and such a setup may lead to an inaccurate height determination under dynamic surveying conditions, e.g., rotating antenna of the mobile receiver.

scholarly journals A FEASIBILITY STUDY ON INCREMENTAL BUNDLE ADJUSTMENT WITH FISHEYE IMAGES AND LOW-COST SENSORS

2019 ◽  
Vol XLII-2/W18 ◽  
pp. 167-171
Author(s):  
A. M. G. Tommaselli ◽  
M. B. Campos ◽  
L. F. Castanheiro ◽  
E. Honkavaara
Keyword(s):  
Microelectromechanical Systems ◽  
Low Cost ◽  
Space Structure ◽  
Bundle Adjustment ◽  
Global Navigation Satellite Systems ◽  
Measurement Unit ◽  
Navigation Systems ◽  
Positional Accuracy ◽  
Integrated Sensor ◽  
Sensor Orientation

Abstract. Low cost imaging and positioning sensors are opening new frontiers for applications in near real-time Photogrammetry. Omnidirectional cameras acquiring images with 360° coverage, when combined with information coming from GNSS (Global Navigation Satellite Systems) and IMU (Inertial Measurement Unit), can efficiently estimate orientation and object space structure. However, several challenges remain in the use of low-cost sensors and image observations acquired by sensors with non-perspective inner geometry. The accuracy of the measurement using low-cost sensors is affected by different sources of errors and sensor stability. Microelectromechanical systems (MEMS) present a large gap between predicted and actual accuracy. This work presents a study on the performance of an integrated sensor orientation approach to estimate sensor orientation and 3D sparse point cloud, using an incremental bundle adjustment strategy and data coming from a low-cost portable mobile terrestrial system composed by off-theshelf navigation systems and a poly-dioptric system (Ricoh Theta S). Experiments were performed in an outdoor area (sidewalk), achieving a trajectory positional accuracy of 0.33 m and a meter level 3D reconstruction.

scholarly journals Impact of UAS Image Orientation on Accuracy of Forest Inventory Attributes

2020 ◽  
Vol 12 (3) ◽  
pp. 404 ◽  
Author(s):  
Luka Jurjević ◽  
Mateo Gašparović ◽  
Anita Simic Milas ◽  
Ivan Balenović
Keyword(s):  
Carrier Phase ◽  
Single Frequency ◽  
Pedunculate Oak ◽  
Dual Frequency ◽  
3D Point Clouds ◽  
Sensor Orientation ◽  
Forested Areas ◽  
Gnss Measurements ◽  
Image Orientation ◽  
Gnss Data

The quality and accuracy of Unmanned Aerial System (UAS) products greatly depend on the methods used to define image orientations before they are used to create 3D point clouds. While most studies were conducted in non- or partially-forested areas, a limited number of studies have evaluated the spatial accuracy of UAS products derived by using different image block orientation methods in forested areas. In this study, three image orientation methods were used and compared: (a) the Indirect Sensor Orientation (InSO) method with five irregularly distributed Ground Control Points (GCPs); (b) the Global Navigation Satellite System supported Sensor Orientation (GNSS-SO) method using non-Post-Processed Kinematic (PPK) single-frequency carrier-phase GNSS data (GNSS-SO1); and (c) using PPK dual-frequency carrier-phase GNSS data (GNSS-SO2). The effect of the three methods on the accuracy of plot-level estimates of Lorey’s mean height (HL) was tested over the mixed, even-aged pedunculate oak forests of Pokupsko basin located in Central Croatia, and validated using field validation across independent sample plots (HV), and leave-one-out cross-validation (LOOCV). The GNSS-SO2 method produced the HL estimates of the highest accuracy (RMSE%: HV = 5.18%, LOOCV = 4.06%), followed by the GNSS-SO1 method (RMSE%: HV = 5.34%, LOOCV = 4.37%), while the lowest accuracy was achieved by the InSO method (RMSE%: HV = 5.55%, LOOCV = 4.84%). The negligible differences in the performances of the regression models suggested that the selected image orientation methods had no considerable effect on the estimation of HL. The GCPs, as well as the high image overlaps, contributed considerably to the block stability and accuracy of image orientation in the InSO method. Additional slight improvements were achieved by replacing single-frequency GNSS measurements with dual-frequency GNSS measurements and by incorporating PPK into the GNSS-SO2 method.

scholarly journals Some New Perspectives on the Multi-user Detection in Uplink Grant-Free NOMA using Deep Neural Network

2021 ◽  
Author(s):  
Shah Mahdi Hasan ◽  
Kaushik Mahata ◽  
Md Mashud Hyder
Keyword(s):  
Neural Network ◽  
Deep Neural Network ◽  
Low Cost ◽  
Base Station ◽  
Data Detection ◽  
Free System ◽  
Active User ◽  
Important Concern ◽  
Wide Range ◽  
Alternative Routes

To support the explosive growth of the Internet of Things (IoT), Uplink (UL) grant-free Non-Orthogonal Multiple Access (NOMA) emerges as a promising technology. It has the potential of offering scalable and low-cost solutions for the resource-constrained Massive Machine Type Communication (mMTC) systems. In principle, the grant-free NOMA enables small signaling overhead and low access latency time by circumventing complicated grant-access based procedures which is commonly found in the legacy wireless networks. In a UL grant-free system, a complete Multi-User Detection (MUD) algorithm not only performs the Active User Detection (AUD) but also the Channel Estimation (CE) and the Data Detection (DD). By exploiting the naturally occurring sparse user activity in the mMTC systems, the MUD problem can be solved using a wide range of Compressive Sensing based algorithms (CS-MUD). However, some alternative routes have been explored in the literature as well. The utility of these algorithms, in general, revolve around some assumptions about the channel or the availability of perfect channel information at the Base Station (BS). How these assumptions are met in a practical circumstance is, however, an important concern. In this work we devise an end-to-end MUD using Deep Neural Network (DNN) where we relax these assumptions. We approximate an ensemble of trained DNN based MUD using Knowledge Distillation (KD) to enable fast AUD at the Base Station (BS). Furthermore, using the inter-resource correlation, we estimate the channels of the active users which is an ill-posed problem otherwise. We carry out elaborate numerical investigation to validate the efficacy of the proposed approach for the UL grant-free NOMA systems.

scholarly journals Assessment of Static Positioning Accuracy Using Low-Cost Smartphone GPS Devices for Geodetic Survey Points’ Determination and Monitoring

2020 ◽  
Vol 10 (15) ◽  
pp. 5308 ◽  
Author(s):  
Marcin Uradziński ◽  
Mieczysław Bakuła
Keyword(s):  
Mobile Phones ◽  
Carrier Phase ◽  
Low Cost ◽  
Satellite System ◽  
Base Station ◽  
Dual Frequency ◽  
Post Processing ◽  
Positioning Accuracy ◽  
Static Mode ◽  
Ambiguity Fixing

Recent developments enable to access raw Global Navigation Satellite System (GNSS) measurements of mobile phones. Initially, researchers using signals gathered by mobile phones for high accuracy surveying were not successful in ambiguity fixing. Nowadays, GNSS chips, which are built in the latest smartphones, deliver code and primarily carrier phase observations available for detailed analysis in post-processing applications. Therefore, we decided to check the performance of carrier phase ambiguity fixing and positioning accuracy results of the latest Huawei P30 pro smartphone equipped with a dual-frequency GNSS receiver. We collected 3 h of raw static data in separate sessions at a known point location. For two sessions, the mobile phone was mounted vertically and for the third one—horizontally. At the same time, a high-class geodetic receiver was used for L1 and L5 signal comparison purposes. The carrier phase measurements were processed using commercial post-processing software with reference to the closest base station observations located 4 km away. Additionally, 1 h sessions were divided into 10, 15, 20 and 30 min separate sub-sessions to check the accuracy of the surveying results in fast static mode. According to the post-processing results, we were able to fix all L1 ambiguities based on Global Positioning System (GPS)-only satellite constellation. In comparison to the fixed reference point position, all three 1 h static session results were at centimeters level of accuracy (1–4 cm). For fast static surveying mode, the best results were obtained for 20 and 30 min sessions, where average accuracy was also at centimeters level.

scholarly journals Robotic Arm Assisted Laser Surgery with LiFi Based Patient Monitoring System

2020 ◽  
Vol 9 (11) ◽  
pp. 150-153
Keyword(s):  
Robotic Surgery ◽  
Monitoring System ◽  
Patient Monitoring ◽  
Low Cost ◽  
Base Station ◽  
The Body ◽  
Alert Message ◽  
Wide Range ◽  
The Future ◽  
Patient Monitoring System

With the advances in electronics and control software, robotic arms are now capable of quick and accurate movement under a wide range of conditions. Robotic surgery has become the most important field of general surgery. This rapid progress is quantitative and qualitative .The common procedures performed in Robotic Field and the future advancements are being discussed in this paper. Along with the existing system of Robotic surgery the advanced instruments and the future possibilities are being discussed. This project will help to solve the existing problems in robotic surgery even in other additional fields. Now a days the limitations of WiFi has reduced the usage in medical field especially. Therefore a LiFi based system will enable to overcome the limitations of Wi-Fi. A continuous monitoring of the vital parameters of the body like temperature, pulse rate and glucose level is also required. Regular interval of time measuring the intensive parameter of the patient’s health with a low cost micro controller and intelligent LiFi based advanced patient monitoring system is developed and if any abnormal condition occurs, it directly sends a message to the doctor’s base station machine via Li-If that particular word no’s particular parameter is out of the range. Doctor can do the fast assessment of the patient’s health without wasting the time with the help of an alert message.

scholarly journals Some New Perspectives on the Multi-user Detection in Uplink Grant-Free NOMA using Deep Neural Network

2021 ◽  
Author(s):  
Shah Mahdi Hasan ◽  
Kaushik Mahata ◽  
Md Mashud Hyder
Keyword(s):  
Neural Network ◽  
Deep Neural Network ◽  
Low Cost ◽  
Base Station ◽  
Data Detection ◽  
Free System ◽  
Active User ◽  
Important Concern ◽  
Wide Range ◽  
Alternative Routes

To support the explosive growth of the Internet of Things (IoT), Uplink (UL) grant-free Non-Orthogonal Multiple Access (NOMA) emerges as a promising technology. It has the potential of offering scalable and low-cost solutions for the resource-constrained Massive Machine Type Communication (mMTC) systems. In principle, the grant-free NOMA enables small signaling overhead and low access latency time by circumventing complicated grant-access based procedures which is commonly found in the legacy wireless networks. In a UL grant-free system, a complete Multi-User Detection (MUD) algorithm not only performs the Active User Detection (AUD) but also the Channel Estimation (CE) and the Data Detection (DD). By exploiting the naturally occurring sparse user activity in the mMTC systems, the MUD problem can be solved using a wide range of Compressive Sensing based algorithms (CS-MUD). However, some alternative routes have been explored in the literature as well. The utility of these algorithms, in general, revolve around some assumptions about the channel or the availability of perfect channel information at the Base Station (BS). How these assumptions are met in a practical circumstance is, however, an important concern. In this work we devise an end-to-end MUD using Deep Neural Network (DNN) where we relax these assumptions. We approximate an ensemble of trained DNN based MUD using Knowledge Distillation (KD) to enable fast AUD at the Base Station (BS). Furthermore, using the inter-resource correlation, we estimate the channels of the active users which is an ill-posed problem otherwise. We carry out elaborate numerical investigation to validate the efficacy of the proposed approach for the UL grant-free NOMA systems.

scholarly journals Some New Perspectives on the Multi-user Detection in Uplink Grant-Free NOMA using Deep Neural Network

2021 ◽  
Author(s):  
Shah Mahdi Hasan ◽  
Kaushik Mahata ◽  
Md Mashud Hyder
Keyword(s):  
Neural Network ◽  
Deep Neural Network ◽  
Low Cost ◽  
Base Station ◽  
Data Detection ◽  
Free System ◽  
Active User ◽  
Important Concern ◽  
Wide Range ◽  
Alternative Routes

To support the explosive growth of the Internet of Things (IoT), Uplink (UL) grant-free Non-Orthogonal Multiple Access (NOMA) emerges as a promising technology. It has the potential of offering scalable and low-cost solutions for the resource-constrained Massive Machine Type Communication (mMTC) systems. In principle, the grant-free NOMA enables small signaling overhead and low access latency time by circumventing complicated grant-access based procedures which is commonly found in the legacy wireless networks. In a UL grant-free system, a complete Multi-User Detection (MUD) algorithm not only performs the Active User Detection (AUD) but also the Channel Estimation (CE) and the Data Detection (DD). By exploiting the naturally occurring sparse user activity in the mMTC systems, the MUD problem can be solved using a wide range of Compressive Sensing based algorithms (CS-MUD). However, some alternative routes have been explored in the literature as well. The utility of these algorithms, in general, revolve around some assumptions about the channel or the availability of perfect channel information at the Base Station (BS). How these assumptions are met in a practical circumstance is, however, an important concern. In this work we devise an end-to-end MUD using Deep Neural Network (DNN) where we relax these assumptions. We approximate an ensemble of trained DNN based MUD using Knowledge Distillation (KD) to enable fast AUD at the Base Station (BS). Furthermore, using the inter-resource correlation, we estimate the channels of the active users which is an ill-posed problem otherwise. We carry out elaborate numerical investigation to validate the efficacy of the proposed approach for the UL grant-free NOMA systems.

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