scholarly journals Temperature-Compensated Spread Spectrum Sound-Based Local Positioning System for Greenhouse Operations

IoT ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 147-160
Author(s):  
Lok Wai Jacky Tsay ◽  
Tomoo Shiigi ◽  
Zichen Huang ◽  
Xunyue Zhao ◽  
Tetsuhito Suzuki ◽  
...  
Keyword(s):  
Sound Velocity ◽  
Spread Spectrum ◽  
Current System ◽  
Low Cost ◽  
Temporal Variations ◽  
Major Effect ◽  
Ease Of Use ◽  
Positioning System ◽  
Positioning Accuracy ◽  
Local Positioning System

A spread spectrum sound-based local positioning system (SSSLPS) has been developed for indoor agricultural robots by our research group. Such an SSSLPS has several advantages, including effective propagation, low cost, and ease of use. When using sound velocity for field position measurements in a greenhouse, spatial and temporal variations in temperature during the day can have a major effect on sound velocity and subsequent positioning accuracy. In this research, a temperature-compensated sound velocity positioning was proposed and evaluated in comparison to a conventional temperature sensor method. Results indicate that this new proposed method has a positioning accuracy to within 20 mm in a 3 m × 9 m ridged greenhouse. It has the potential to replace the current system of using the temperature sensors in a greenhouse.

Developing a Low-Cost, High Performance, SDR-Based Local Positioning System

2021 ◽  
Author(s):  
Fernando Palafox ◽  
Lyndsay Ruane ◽  
Scott Palo ◽  
Dennis Akos
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Positioning System ◽  
Local Positioning System

scholarly journals Easily-Deployable Acoustic Local Positioning System Based on Auto-Calibrated Wireless Beacons

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1385 ◽  
Author(s):  
José Moreno ◽  
Fernando Álvarez ◽  
Teodoro Aguilera ◽  
José Paredes
Keyword(s):  
Spread Spectrum ◽  
Low Cost ◽  
Experimental Tests ◽  
Real Time System ◽  
Positioning Systems ◽  
Local Positioning System ◽  
Update Rate ◽  
Positioning Algorithm ◽  
Node Position

Self-calibrated Acoustic Local Positioning Systems (ALPS) generally require a high consumption of hardware and software resources to obtain the user’s position at an acceptable update rate. To address this limitation, this work proposes a self-calibrated ALPS based on a software/hardware co-design approach. This working architecture allows for efficient communications, signal processing tasks, and the running of the positioning algorithm on low-cost devices. This fact also enables the real-time system operation. The proposed system is composed of a minimum of four RF-synchronized active acoustic beacons, which emit spread-spectrum modulated signals to position an unlimited number of receiver nodes. Each receiver node estimates the beacons’ position by means of an auto-calibration process and then computes its own position by means of a 3D multilateration algorithm. A set of experimental tests has been carried out where the feasibility of the proposed system is demonstrated. In these experiments, accuracies below 0.1 m are obtained in the determination of the receptor node position with respect to the set of previously-calibrated beacons.

scholarly journals Assessment of the Steering Precision of a Hydrographic USV along Sounding Profiles Using a High-Precision GNSS RTK Receiver Supported Autopilot

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5637
Author(s):  
Łukasz Marchel ◽  
Cezary Specht ◽  
Mariusz Specht
Keyword(s):  
High Precision ◽  
Low Cost ◽  
Path Following ◽  
Satellite System ◽  
Magnetic Compass ◽  
Reference Station ◽  
Positioning System ◽  
Positioning Accuracy ◽  
Unmanned Surface Vehicles ◽  
Global Navigation Satellite

Unmanned Surface Vehicles (USV) are increasingly used to perform numerous tasks connected with measurements in inland waters and seas. One of such target applications is hydrography, where traditional (manned) bathymetric measurements are increasingly often realized by unmanned surface vehicles. This pertains especially to restricted or hardly navigable waters, in which execution of hydrographic surveys with the use of USVs requires precise maneuvering. Bathymetric measurements should be realized in a way that makes it possible to determine the waterbody’s depth as precisely as possible, and this requires high-precision in navigating along planned sounding profiles. This paper presents research that aimed to determine the accuracy of unmanned surface vehicle steering in autonomous mode (with a Proportional-Integral-Derivative (PID) controller) along planned hydrographic profiles. During the measurements, a high-precision Global Navigation Satellite System (GNSS) Real Time Kinematic (RTK) positioning system based on a GNSS reference station network (positioning accuracy: 1–2 cm, p = 0.95) and a magnetic compass with the stability of course maintenance of 1°–3° Root Mean Square (RMS) were used. For the purpose of evaluating the accuracy of the vessel’s path following along sounding profiles, the cross track error (XTE) measure, i.e., the distance between an USV’s position and the hydrographic profile, calculated transversely to the course, was proposed. The tests were compared with earlier measurements taken by other unmanned surface vehicles, which followed the exact same profiles with the use of much simpler and low-cost multi-GNSS receiver (positioning accuracy: 2–2.5 m or better, p = 0.50), supported with a Fluxgate magnetic compass with a high course measurement accuracy of 0.3° (p = 0.50 at 30 m/s). The research has shown that despite the considerable difference in the positioning accuracy of both devices and incomparably different costs of both solutions, the authors proved that the use of the GNSS RTK positioning system, as opposed to a multi-GNSS system supported with a Fluxgate magnetic compass, influences the precision of USV following sounding profiles to an insignificant extent.

scholarly journals Research on the designing of pneumatic positioning units controlled with valves commanded in modulated pulses

2019 ◽  
Vol 290 ◽  
pp. 08003
Author(s):  
Mihai Avram ◽  
Victor Constantin ◽  
Emil-Ionuț Niță
Keyword(s):  
Closed Loop ◽  
Low Cost ◽  
Positioning System ◽  
Electronic Control ◽  
Mechatronic System ◽  
Positioning Accuracy ◽  
Braking System ◽  
Electronic Control System ◽  
New Type ◽  
Specific Construction

This article presents the hardware structure for a new type of closed loop positioning system using pneumatic energy. In brief, when the mobile subassembly of the system is about to reach a targeted position its speed is controlled by the small-sized pneumatic electro valves, which are commanded in modulated pulses. Here, we developed an electronic control system of which memory has a specially designed algorithm. In addition, the pneumatic engine has a specific construction that integrates a transducer of position as well as a braking system. The proposed mechatronic system is described by good positioning accuracy and low cost.

MAKAN: A low‐cost low‐complexity local positioning system

Navigation ◽  
2019 ◽  
Vol 66 (2) ◽  
pp. 401-415 ◽  
Author(s):  
Ghasem Kahe ◽  
Farhad Masoumi Ganjgah
Keyword(s):  
Low Cost ◽  
Low Complexity ◽  
Positioning System ◽  
Local Positioning System

scholarly journals Characterization of an Ultrasonic Local Positioning System for 3D Measurements

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2794 ◽  
Author(s):  
Khaoula Mannay ◽  
Jesús Ureña ◽  
Álvaro Hernández ◽  
Mohsen Machhout ◽  
Taoufik Aguili
Keyword(s):  
Low Cost ◽  
Likelihood Estimation ◽  
Indoor Positioning ◽  
Global Navigation Satellite Systems ◽  
Positioning System ◽  
Fusion Algorithm ◽  
Coverage Area ◽  
Positioning Systems ◽  
Indoor Location ◽  
Local Positioning System

Indoor location and positioning systems (ILPS) are used to locate and track people, as well as mobile and/or connected targets, such as robots or smartphones, not only inside buildings with a lack of global navigation satellite systems (GNSS) signals but also in constrained outdoor situations with reduced coverage. Indoor positioning applications and their interest are growing in certain environments, such as commercial centers, airports, hospitals or factories. Several sensory technologies have already been applied to indoor positioning systems, where ultrasounds are a common solution due to its low cost and simplicity. This work proposes a 3D ultrasonic local positioning system (ULPS), based on a set of three asynchronous ultrasonic beacon units, capable of transmitting coded signals independently, and on a 3D mobile receiver prototype. The proposal is based on the aforementioned beacon unit, which consists of five ultrasonic transmitters oriented towards the same coverage area and has already been proven in 2D positioning by applying hyperbolic trilateration. Since there are three beacon units available, the final position is obtained by merging the partial results from each unit, implementing a minimum likelihood estimation (MLE) fusion algorithm. The approach has been characterized, and experimentally verified, trying to maximize the coverage zone, at least for typical sizes in most common public rooms and halls. The proposal has achieved a positioning accuracy below decimeters for 90% of the cases in the zone where the three ultrasonic beacon units are available, whereas these accuracies can degrade above decimeters according to whether the coverage from one or more beacon units is missing. The experimental workspace covers a large volume, where tests have been carried out at points placed in two different horizontal planes.

scholarly journals A Signal Recovery Method Based on Bayesian Compressive Sensing

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Hao Zhanjun ◽  
Li Beibei ◽  
Dang Xiaochao
Keyword(s):  
Compressive Sensing ◽  
Human Body ◽  
Positioning System ◽  
Complex Environments ◽  
Positioning Accuracy ◽  
Recovery Method ◽  
Positioning Systems ◽  
Local Positioning System ◽  
Crawling Waves ◽  
The Impact

In a precise positioning system, weak signal errors caused by the influence of a human body on signal transmission in complex environments are a main cause of the reduced reliability of communication and positioning accuracy. Therefore, eliminating the influence of interference from human crawling waves on signal transmissions in complex environments is an important task in improving positioning systems. To conclude, an experimental environment is designed in this paper and a method using the Ultra-Wideband (UWB) Local Positioning System II (UWB LPS), called Bayesian Compressed Sensing-Crawling Waves (BCS-CW), is proposed to eliminate the impact of crawling waves using Bayesian compressive sensing. First, analyse the transmission law for crawling waves on the human body. Second, Bayesian compressive sensing is used to recover the UWB crawling wave signal. Then, the algorithm is combined with the maximum likelihood estimation and iterative approximation algorithms to determine the label position. Finally, through experimental verification, the positioning accuracy of this method is shown to be greatly improved compared to that of other algorithms.

scholarly journals A Noise Tolerant Spread Spectrum Sound-Based Local Positioning System for Operating a Quadcopter in a Greenhouse

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1981 ◽  
Author(s):  
Zichen Huang ◽  
Lok Wai Jacky Tsay ◽  
Tomoo Shiigi ◽  
Xunyue Zhao ◽  
Hiroaki Nakanishi ◽  
...  
Keyword(s):  
Precision Agriculture ◽  
Spread Spectrum ◽  
Multiple Access ◽  
Acoustic Noise ◽  
Noise Spectrum ◽  
Broadband Noise ◽  
Positioning System ◽  
Noise Tolerance ◽  
Local Positioning System ◽  
Noise Tolerant

Quadcopters are beginning to play an important role in precision agriculture. In order to localize and operate the quadcopter automatically in complex agricultural settings, such as a greenhouse, a robust positioning system is needed. In previous research, we developed a spread spectrum sound-based local positioning system (SSSLPS) with a 20 mm accuracy within a 30 × 30 m greenhouse area. In this research, a noise tolerant SSSLPS was developed and evaluated. First, the acoustic noise spectrum emitted by the quadcopter was documented, and then the noise tolerance properties of SSSounds were examined and tested. This was done in a greenhouse with a fixed quadcopter (9.75 N thrust) with the positioning system mounted on it. The recorded quadcopter noise had a broadband noise compared to the SSSound. Taking these SSSound properties into account, the noise tolerance of the SSSLPS was improved, achieving a positioning accuracy of 23.2 mm and 31.6 mm accuracy within 12 × 6 m for both Time-division Multiple Access (TDMA) and Frequency-division Multiple Access (FDMA) modulation. The results demonstrate that the SSSLPS is an accurate, robust positioning system that is noise tolerant and can used for quadcopter operation even within a small greenhouse.

Supermarket Trolley Positioning System Based on ZigBee

2014 ◽  
Vol 644-650 ◽  
pp. 2788-2792
Author(s):  
Zheng Zhang ◽  
Xing Peng Tao ◽  
Lun Zeng ◽  
Chan Wang
Keyword(s):  
Power Consumption ◽  
Full Advantage ◽  
Ad Hoc Network ◽  
Field Experiments ◽  
Ad Hoc ◽  
Low Cost ◽  
Low Power Consumption ◽  
Positioning System ◽  
Positioning Accuracy ◽  
Time Position

At present, in many large supermarkets, the trolley management mainly rely on manual, which increases management costs and the burden of work, therefore, the supermarket trolley positioning system is proposed to solve this problem. The positioning system takes full advantage of ZigBee technology’s low power consumption, low cost and ad hoc network, the node module is embedded into the supermarket trolley and positioned by positioning engine, using PC interface developed by VB6.0 to display its real-time position. Field experiments show that its positioning accuracy is less than 3m, The staffs easily know the location of trolleys when they sit in the monitor room. It can reduce the costs and the burden of work.

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