scholarly journals Space-Based Optical Observations on Space Debris via Multipoint of View

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Zhao Li ◽  
Yidi Wang ◽  
Wei Zheng
Keyword(s):  
Optical Sensors ◽  
Orbit Determination ◽  
Space Debris ◽  
Cost Benefit ◽  
Point Of View ◽  
Optical Observations ◽  
Design Parameters ◽  
Spacecraft Formation ◽  
Initial Orbit Determination ◽  
Cost Benefit Ratio

In this paper, the space debris catalogue in LEO is fulfilled using multipoint of view (MPOV) observations constructed by a spacecraft formation. The dual-point of view (DPOV) observation is employed because it has higher cost-benefit ratio than other MPOV methods, and it required that the target is detectable for multiple optical sensors simultaneously. This condition is matched by designing the orbit of formation and the installation angles of sensors without frequent attitude maneuvers. The design parameters are optimized to maximize the matching degree of observation constraints to improve the coverage performance of the formation, and the equivalent ranging error is taken into account to ensure the orbit determination accuracy. Finally, the system capabilities of different schemes are compared by simulations. For the schemes with the same number of platforms, simulation results show that the initial orbit determination accuracy of the proposed scheme is higher.

scholarly journals Análisis económico: un estudio de caso en Jatropha curcas L. mediante la metodología de presupuestos parciales

2018 ◽  
Vol 29 (1) ◽  
pp. 95
Author(s):  
Juan Manuel Ávalos-Cerdas ◽  
Alexis Villalobos-Monge
Keyword(s):  
Jatropha Curcas ◽  
Cost Benefit ◽  
Point Of View ◽  
Agricultural Experiment Station ◽  
Polyphagotarsonemus Latus ◽  
Marginal Rate ◽  
Cost Benefit Ratio ◽  
Agricultural Experiment ◽  
Marginal Rate Of Return ◽  
Important Form

The methodology of partial budgets is an important form of economic analysis that contemplates that the costs between different agricultural trials differ without having to arrive directly to the production site, a fact that does not always happen on this type of experiments. The objective of the present work was to perform an analysis by means of partial budgets, in an experimental plot of Jatropha curcas. The experiment was carried out at the Fabio Baudrit Moreno Agricultural Experiment Station, La Garita, Alajuela, Costa Rica, between January and August,2014. An evaluation of the effect of five products against Polyphagotarsonemus latus on Jatropha curcas plants was performed,this products are:hexithiazox (1 ml/l of water), sulfur (10 kg/ha),propargite (4 kg/ha),spiromesifen(0.5 l/ha) and abamectin (1.5 l/ha). Two products applications were carried out, each application happened twenty-two days apart. After each application, the number of mites (eggs, larvae and adults) present on each treatment was evaluated. The methodology of partial budgets was used with an adjustment in order to determine which treatment from an economical point of view was the best. The results indicated that the treatment with the best cost-benefit ratio was abamectin with MRT values (marginal rate of return) of 17.1%, 4.6%, and 4.1%, for eggs, larvae and adults, respectively; followed by spiromesifen with a TRM for eggs of 5%, larvae of 1.8%, and adults of 3.8%, and finally sulfur; according to the TRM analysis. This indicates that the product with the lowest cost is not necessarily the product with the best results.

Comparison of angles only initial orbit determination algorithms for space debris cataloguing

2012 ◽  
Vol 4 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Fran M. Fadrique ◽  
Alberto A. Maté ◽  
Joan J. Grau ◽  
Jaime F. Sánchez ◽  
Laura A. García
Keyword(s):  
Orbit Determination ◽  
Space Debris ◽  
Initial Orbit Determination ◽  
Initial Orbit

scholarly journals APPARILLO: a fully operational and autonomous staring system for LEO debris detection

2021 ◽  
Author(s):  
Paul Wagner ◽  
Tim Clausen
Keyword(s):  
Orbit Determination ◽  
Space Debris ◽  
Imaging System ◽  
Tracking System ◽  
Precise Orbit Determination ◽  
Ccd Camera ◽  
Low Earth Orbit ◽  
Laser Ranging ◽  
Distance Measurements ◽  
Initial Orbit Determination

AbstractFor safe operation of active space crafts, the space debris population needs to be continuously scanned, to avoid collisions of active satellites with space debris. Especially the low Earth orbit (LEO) shows higher risks of collisions due to the highest density of orbital debris. Laser ranging stations can deliver highly accurate distance measurements of debris objects allowing precise orbit determination and more effective collision avoidance. However, a laser ranging station needs accurate a priori orbit information to track an orbital object. To detect and track unknown orbital objects in LEO, here, a passive optical staring system is developed for autonomous 24/7 operation. The system is weather-sealed and does not require any service to perform observations. To detect objects, a wide-angle imaging system with 10° field of view equipped with an astronomical CCD camera was designed and set up to continuously observe the sky for LEO objects. The system can monitor and process several passing objects simultaneously without limitations. It automatically starts an observation, processes the images and saves the 2D angular measurements of each object as equatorial coordinates in the TDM standard. This allows subsequent initial orbit determination and handover to a laser tracking system. During campaigns at twilight the system detected up to 36 objects per hour, with high detection efficiencies of LEO objects larger than 1 m3. It is shown that objects as small as 0.1 m3 can be detected and that the estimated precision of the measurements is about 0.05° or 7 × the pixel scale.

scholarly journals A New Triangulation Algorithm for Positioning Space Debris

2021 ◽  
Vol 13 (23) ◽  
pp. 4878
Author(s):  
Long Chen ◽  
Chengzhi Liu ◽  
Zhenwei Li ◽  
Zhe Kang
Keyword(s):  
Orbit Determination ◽  
Space Debris ◽  
Position Error ◽  
Optical Measurements ◽  
Mean Square ◽  
Positioning Error ◽  
Positioning Accuracy ◽  
Analytical Expression ◽  
Initial Orbit Determination ◽  
Initial Orbit

A single electro-optical (EO) sensor used in space debris observation provides angle-only information. However, space debris position can be derived using simultaneous optical measurements obtained from two EO sensors located at two separate observation sites, and this is commonly known as triangulation. In this paper, we propose a new triangulation algorithm to determine space debris position, and its analytical expression of Root-Mean-Square (RMS) position error is presented. The simulation of two-site observation is conducted to compare the RMS positioning error of the proposed triangulation algorithm with traditional triangulation algorithms. The results show that the maximum RMS position error of the proposed triangulation algorithm is not more than 200 m, the proposed triangulation algorithm has higher positioning accuracy than traditional triangulation algorithms, and the RMS position error obtained in the simulation is nearly consistent with the analytical expression of RMS position error. In addition, initial orbit determination (IOD) is carried out by using the triangulation positioning data, and the results show that the IOD accuracy of two-site observation is significantly higher than that of the single-site observation.

scholarly journals GEOMETRIC PERFORMANCE OF A CAMERA WITH SINGLE SENSOR AND MULTIPLE HEADS

2020 ◽  
Vol XLIII-B1-2020 ◽  
pp. 389-396 ◽  
Author(s):  
A. M. G. Tommaselli ◽  
A. Berveglieri ◽  
N. N. Imai ◽  
G. H. Santos ◽  
E. A. S. Moriya ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Cost Benefit ◽  
Spectral Bands ◽  
Cost Benefit Ratio ◽  
Close Range ◽  
New Type ◽  
Single Sensor ◽  
Digital Agriculture ◽  
Calibration Techniques ◽  
New Sensors

Abstract. Remote sensing with lightweight optical sensors is becoming a powerful tool to solve many problems in agriculture. Achieving the level of spatial and spectral resolutions required for this type of detection at an acceptable cost-benefit ratio has motivated the development of new sensors which must be lightweight to be carried by mobile robots either aerial or terrestrial. One new type of multiple head cameras has been developed by Agrowing, an Israeli company developing technology for digital agriculture. The aim of this paper is to analyse the geometric features of an Agrowing dual head camera trough calibration experiments. The sensor was calibrated following two options, depending on the cropping technique used to produce the 4 spectral bands. Different calibration techniques were also used and very accurate results were achieved. Experiments with data collected with a UAV also confirmed the results achieved with close range calibration.

scholarly journals Technological and socio-economic analysis of the local production system of the pink Zaragoza bean (Phaseolus vulgaris L.) in the Caribbean of Colombia

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Antonio María Martínez-Reina ◽  
Liliana María Grandett-Martínez ◽  
Lilibet Tordecilla-Zumaqué ◽  
María Del Valle Rodríguez-Pinto ◽  
Carina Cecilia Cordero-Cordero ◽  
...  
Keyword(s):  
Production System ◽  
Cost Benefit ◽  
Point Of View ◽  
Production Costs ◽  
Sale Price ◽  
Economic Point ◽  
Profitability Analysis ◽  
Average Production ◽  
Predominant Type ◽  
Cost Benefit Ratio

The objective of this study was to characterize the Zaragoza pink bean production system in the Colombian Caribbean from the technical and economic point of view. A survey was randomly applied to 32 farmers in producing areas. The data were analyzed using descriptive statistics, measurements of central tendency and contingency tables. The economic return calculations were made using a production cost pattern and economic profitability analysis techniques. The results showed that the average experience in cultivation is 12 years; the average age of the farmers is 48 years; the predominant type of tenure is property in 63% of the sample; and the mode of the area devoted to this crop is 0.5 ha. The use of family labor predominates in 65% of cases. 90% of the production is destined for the market, 8% is destined for self-consumption, and 2% is for seeds. Production costs correspond to 1,437 USD/ha, the average production is 1,700 kg ha-1, and the average sale price was 0.886 USD/kg, which generates a cost benefit ratio of 1.43% in three months of the productive cycle, from sowing to postharvest. This crop is profitable and stable inasmuch as its yields recover costs and generate profits for producers.

scholarly journals CubeSat formation architecture for small space debris surveillance and orbit determination

2021 ◽  
pp. 37-46
Author(s):  
Anton Afanasev ◽  
Shamil Biktimirov
Keyword(s):  
Optical Sensors ◽  
Orbit Determination ◽  
Space Debris ◽  
Small Space ◽  
Tetrahedral Configuration ◽  
Mean Squared Errors ◽  
Information Filter ◽  
Synchronous Orbit ◽  
Optimal Configurations ◽  
Short Arc

Introduction: Satellites which face space debris cannot track it throughout the whole orbit due to natural limitations of their optical sensors, sush as field of view, Earth occultation, or solar illumination. Besides, the time of continuous observations is usually very short. Therefore, we are trying to offer the most effective configuration of optical sensors in order to provide short-arc tracking of a target piece of debris, using a scalable Extended Information Filter. Purpose: The best scenario for short-arc tracking of a space debris orbit using multipoint optical sensors. Results: We have found optimal configurations for groups of satellites with optical sensors which move along a sun-synchronous orbit.  Debris orbit determination using an Extended Information Filter and measurements from multipoint sensors was simulated, and mean squared errors of the target's position were calculated. Based on the simulation results for variouos configurations, inter-satellite distances and measurement time, the most reliable scenario (four satellites in tetrahedral configuration) was found and recommended for practical use in short-arc debris tracking.

scholarly journals Cost-benefit relationship of keeping dantrolene stocks from the point of view of healthcare institutions

2020 ◽  
Vol 48 (2) ◽  
pp. 63-70
Author(s):  
David A. Rincón-Valenzuela ◽  
Ciro Gómez-Ardila
Keyword(s):  
Decision Tree ◽  
Annual Cost ◽  
Specific Treatment ◽  
Cost Benefit ◽  
Point Of View ◽  
Economic Consequences ◽  
Operating Theater ◽  
Cost Benefit Ratio ◽  
The Cost ◽  
Relationship Of

Introduction: Malignant hyperthermia (MH) is an acute syndrome triggered by certain anesthetic medications. Dantrolene is the only specific treatment for MH crises. Without treatment, lethality may be as high as 80%. In Colombia, it is not mandatory to keep dantrolene supplies in stock. Objective: To establish the cost-benefit ratio, from the perspective of healthcare institutions, of keeping dantrolene supplies in stock in the operating theater. Methods: Using a decision tree, a Monte Carlo simulation was run with 10,000 scenarios to determine the median annual cost of keeping full or partial stocks (36 or 12 vials x 20 mg, respectively) of dantrolene. For the option of not keeping supplies in stock, the cost threshold was calculated where the expected value of both alternatives of the decision tree is equalized. Indifference curves were constructed for complete and partial supplies. Results: The median annual cost was estimated at 6.6 million Colombian pesos (COP) for full dantrolene supplies, and at COP 2.2 million for partial supplies. The median economic consequence threshold for 1 death due to the unavailability of dantrolene was estimated at COP 18.5 million for full supplies, and at COP 57.0 million for partial supplies. Conclusion: If, as a result of the unavailability of dantrolene, the economic consequences of a death due to MH exceed the threshold of COP 57.0 or COP 18.5 million, the purchase of full or partial stocks, respectively, is justified.

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