Loran-C Chain and UTC Synchronisation

2000 ◽  
Vol 53 (2) ◽  
pp. 215-223
Author(s):  
William F. Roland
Keyword(s):  
Time Management ◽  
Service Providers ◽  
Digital Signal ◽  
Timing Control ◽  
Control Techniques ◽  
Timing Information ◽  
History Of ◽  
And Control ◽  
Improved Accuracy ◽  
Measurement And Control

There has been much discussion recently implying that Loran-C chain synchronisation using ‘System Area Monitor’ (SAM) control and using ‘Time of Transmission (or Emission)’ (TOT or TOE) are incompatible mechanisations of Loran-C chain time management because of their differing impact on users. Further, the mechanisation of UTC synchronisation is described as either satellite (GPS/GLONASS) based or Loran Chain measurement based, thereby excluding integrated use of both techniques for reliability. These differences are not mutually exclusive. Well-defined chain synchronisation can logically apply all measurement and control techniques as well as providing improved accuracy. This paper defines synchronisation and describes the history of Loran-C synchronisation control and the current methods employed. The existence of Cesium Standards at Loran stations, and the recent introduction of digital signal processing receivers, have greatly changed the potential for extremely precise timing control, detection of extraordinary timing changes, and the maintenance of very tight UTC synchronisation. This paper describes a number of techniques for defining, observing and applying the various sources of timing information, optimising performance for users and simplifying implementation for service providers.

Introducing Temperature Measurement and Control Techniques to Engineering Undergraduate Students in the Gulf Region

2008 ◽  
Author(s):  
Peter Rodgers ◽  
Arman Molki
Keyword(s):  
Engineering Education ◽  
Temperature Measurement ◽  
Temperature Control ◽  
Instrumentation Amplifier ◽  
Gulf Region ◽  
Linear Temperature ◽  
Control Techniques ◽  
The Third ◽  
And Control ◽  
Measurement And Control

Hands-on laboratory skills play a vital role in providing students with a sound understanding of the scientific fundamentals and their application in solving real-life engineering problems. One of the essential laboratory based courses taught at our Institute is Introduction to Measurements and Instrumentation. The design and implementation of such a course has been well documented in Western engineering education, but presents specific challenges in the Gulf region due to economical, social and cultural factors. This paper discusses the adaptation of corresponding Western courses to undergraduate mechanical engineering studies in the Gulf region. Laboratory exercises for temperature measurement and control are described, which consist of four modules, each building upon the other. In each module, students learn how to design an accurate measuring system, and process and interpret collected data. In the first module, the students are required to build a thermocouple reader using an AD620 instrumentation amplifier and to compare measurements with NIST reference tables. The second module is an introduction to LabVIEW, a graphical data acquisition programming language. The students are required to write a LabVIEW program to record multiple thermocouple signals from a heated plate under varying convective cooling conditions, using a high resolution temperature logger with on-board signal conditioning. The third and fourth modules focus on temperature control techniques. In the third laboratory exercise, the students are required to construct an electrical circuit using a low-power PCB relay and NPN bipolar transistor to develop a bang-bang linear temperature controller. The program created in module two is modified to have the heater operation automatically controlled for a fixed temperature set point. In module four, the students replace the bang-bang controller built in the previous lab with a commercially available PID controller and explore the differences between PID and linear temperature control systems. For each module, students are required to submit a formal report covering the theoretical background, the experimental procedure employed, uncertainty analysis, and conclusions and recommendations. An effective teaching strategy is outlined that covers the fundamental concepts of temperature measurement and control through carefully designed experiments, with sample results presented. Emphasis is placed on the tailoring of the course topics to engineering education in the Gulf region.

scholarly journals Automated Measurement and Control of Germination Paper Water Content

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2232
Author(s):  
Lina Owino ◽  
Marvin Hilkens ◽  
Friederike Kögler ◽  
Dirk Söffker
Keyword(s):  
Water Content ◽  
Water Deficit ◽  
Plant Development ◽  
Growth Substrate ◽  
Irrigation Amount ◽  
Control Approach ◽  
Predictive Controller ◽  
And Control ◽  
Improved Accuracy ◽  
Measurement And Control

Germination paper (GP) is used as a growth substrate in plant development studies. Current studies bear two limitations: (1) The actual GP water content and variations in GP water content are neglected. (2) Existing irrigation methods either maintain the GP water content at fully sufficient or at a constant deficit. Variation of the intensity of water deficit over time for plants grown on GP is not directly achievable using these methods. In this contribution, a new measurement and control approach was presented. As a first step, a more precise measurement of water content was realized by employing the discharging process of capacitors to determine the electrical resistance of GP, which is related to the water content. A Kalman filter using an evapotranspiration model in combination with experimental data was used to refine the measurements, serving as the input for a model predictive controller (MPC). The MPC was used to improve the dynamics of the irrigation amount to more precisely achieve the required water content for regulated water uptake in plant studies. This is important in studies involving deficit irrigation. The novel method described was capable of increasing the accuracy of GP water content control. As a first step, the measurement system achieved an improved accuracy of 0.22 g/g. The application of a MPC for water content control based on the improved measurement results in an overall control accuracy was 0.09 g/g. This method offers a new approach, allowing the use of GP for studies with varying water content. This addressed the limitations of existing plant growth studies and allowed the prospection of dependencies between dynamic water deficit and plant development using GP as a growth substrate for research studies.

scholarly journals Design of An Intelligent Split-type Electricity Utilization Measurement and Control Terminal for Local Household Energy Management and Optimization

2018 ◽  
Vol 53 ◽  
pp. 01010
Author(s):  
Baiming Xie ◽  
Lefeng Cheng ◽  
Chao Ding ◽  
Shouyuan Shi ◽  
Zhukui Tan ◽  
...  
Keyword(s):  
Energy Management ◽  
Demand Response ◽  
Lithium Ion ◽  
Digital Signal ◽  
Household Energy ◽  
Intelligent Terminal ◽  
Home Energy Management ◽  
Control Terminal ◽  
And Control ◽  
Measurement And Control

It is of great significance to implement automatic demand response (ADR) in the energy Internet based on accurate measurement and control of electricity utilization devices using intelligent terminals. Current intelligent terminals lack flexibility and possess weak data collection and processing capabilities. On this basis, this paper developed an intelligent split-type electricity utilization measurement and control terminal for local household energy management and optimization. This intelligent terminal has capabilities of digital signal processing and infrared-based precision control, which is composed of two separate parts: the device body and the infrared controller. Among them, the device body includes DSP chip, electrical sampling circuit, ADC chip, WiFi module, ZigBee module, etc. The infrared controller contains single-chip microcomputer, ZigBee module, infrared encoding and transmit-receiving module, and lithium-ion battery. The device body is able to provide commands to the infrared controller according to the collected electricity utilization information, environmental information and comprehensive demand response requirements, thereby accurately adjusting the operating status of the loads, namely the electrical household appliances. Due to the split-type and rechargeable design, this intelligent terminal is able to adapt to a complex home environment, laying the hardware foundation for effective home energy management and optimization and facilitating household loads participating in demand response, especially automatic demand response.

scholarly journals Measurement and control techniques in geothermal power plants

1979 ◽  
Author(s):  
J.F. Whitbeck ◽  
R.H. Dart ◽  
J.D. Miller ◽  
D.R. Brewer
Keyword(s):  
Power Plants ◽  
Control Techniques ◽  
Geothermal Power ◽  
And Control ◽  
Measurement And Control

scholarly journals Recent Development of Measurement and Control Techniques

1965 ◽  
Vol 51 (1) ◽  
pp. 86-98
Author(s):  
Kanichiro KATSURA ◽  
Takashi ISOBE
Keyword(s):  
Control Techniques ◽  
And Control ◽  
Measurement And Control

Control of segment length or force in isolated papillary muscle: an adaptive approach

1989 ◽  
Vol 256 (6) ◽  
pp. H1726-H1734 ◽  
Author(s):  
J. N. Peterson ◽  
W. C. Hunter ◽  
M. R. Berman
Keyword(s):  
Muscle Length ◽  
Adaptive Method ◽  
Current Control ◽  
Segment Length ◽  
Control Techniques ◽  
Feedback Strategies ◽  
And Control ◽  
Measurement And Control ◽  
Total Muscle ◽  
Command Signal

Mechanical studies of isolated cardiac muscle are complicated as a result of damage inflicted on the ends of the muscle during excision and mounting procedures. Inhomogeneities between the healthy central and weakened end portions of the muscle make it difficult to interpret studies where only total muscle length is controlled. Measurement and control of central segment length is clearly desirable but fraught with technical difficulties. We present a novel application of adaptive control methods that minimizes the difficulties encountered with current control techniques. This method, which allows control of either segment length or force, takes advantage of the repetitive, periodic nature of contractions. Here deviations of measured segment length or force signals from a desired response during one twitch are used to modify the muscle length command signal for use on the next twitch. This process continues for successive twitches until either segment length or force is within desired limits. The adaptive method allows greater stability and immunity to noise than classical feedback strategies.

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