Analysis of GPS/EGNOS Positioning Quality Using Different Ionospheric Models in UAV Navigation.

Unmanned aerial vehicles (UAVs) have become very popular tools for geoinformation acquisition in recent years. They have also been applied in many other areas of life. Their navigation is highly dependent on global navigation satellite systems (GNSS). The European Geostationary Navigation Overlay Service (EGNOS) is intended to support GNSSs during positioning, mainly for aeronautical applications. The research presented in this paper concerns the analysis of the positioning quality of a modified GPS/EGNOS algorithm. The calculations focus on the source of ionospheric delay data as well as on the aspect of smoothing code observations with phase measurements. The modifications to the algorithm concerned the application of different ionospheric models for position calculation. Consideration was given to the EGNOS ionospheric model, the Klobuchar model applied to the GPS system, the Klobuchar model applied to the BeiDou system, and the NeQuick model applied to the Galileo system. The effect of removing ionospherical corrections from GPS/EGNOS positioning on the results of the determination of positioning quality was also analysed. The results showed that the original EGNOS ionospheric model maintains the best accuracy results and a better correlation between horizontal and vertical results than the other models examined. The additional use of phase-smoothing of code observations resulted in maximum horizontal errors of approximately 1.3 m and vertical errors of approximately 2.2 m. It should be noted that the results obtained have local characteristics related to the area of north-eastern Poland.

Corrigendum: Systematic review on fiscal policy interventions in nutrition.

[This corrects the article DOI: 10.3389/fnut.2022.967494.].

PROTOCOL: The effects of agricultural output market access interventions on agricultural, socio-economic and food and nutrition security outcomes in low- and middle-income countries: A systematic review.

Development agencies and international donors' efforts are increasingly focusing on better integrating poor and remote farmers into agricultural markets to address the chronic issues of rural poverty and hunger in low- and middle-income countries. Using systematic methods for information retrieval, critical appraisal and evidence synthesis, this research aims to examine evidence on the effects of five focal types of agricultural market access interventions: (i) farm-to-market transport infrastructure interventions; (ii) output market information interventions; (iii) initiatives creating new marketplaces and alternative marketing opportunities; (iv) contract farming initiatives; (v) interventions improving storage infrastructure. In this review, we will study evidence of the magnitude and direction of intervention effects on agricultural, socio-economic, and food and nutrition security outcomes. We will examine evidence of the distribution of reported effects across different contexts, interventions and sub-groups of the population (e.g., according to sex, socio-economic status, farm size, etc.). We will also report on included studies' risk of bias and on what evidence is available on intervention costs, or their cost-effectiveness. This protocol outlines this review's planned methods and the criteria for selecting and including studies in its analysis.

Systematic review on fiscal policy interventions in nutrition.

Introduction: Both the World Health Organization and the Lancet Series on Adolescent nutrition recommend that governments adopt fiscal policies to combat diet-related non-communicable diseases (NCDs). However, rigorous, systematic evidence regarding the effects of these interventions is lacking. Methods: We synthesize the available evidence regarding the impacts of taxes and subsidies that directly affect consumer prices on availability and accessibility of foods and beverages, purchasing behavior, diet quality, health and well-being outcomes as well as considerations for implementation, sustainability and equity. Results: Our initial search returned 2,113 de-duplicated studies, and ultimately 24 impact evaluations and two systematic reviews met final eligibility criteria and represented unique evaluations. Our meta-analysis of these studies suggests that taxes may decrease purchases of taxed beverages (SMD = -0.14 [95% CI: -0.29 to -0.07], n = 15). Results should be interpreted cautiously due to considerable heterogeneity (Q(14) = 335.19, p = 0.01, τ ^ 2 = 0.03 , I 2 = 95.82%). Discussion: The evidence base is too limited to draw conclusions about the effects of taxes on beverages and calorie-dense foods on purchases, or on the effects of subsidies on purchasing or diet quality. Overall, the evidence base is inconclusive on whether fiscal policies can meaningfully influence the availability and accessibility of foods and beverages, diet quality, and health outcomes. Policymakers implementing fiscal policies should consider information campaigns on health benefits and health risks associated with certain food and beverage consumption. For taxes, exposure to health information may amplify signaling effects of taxes and reduce avoidance behaviors, such as cross-border shopping. Future evaluations should diversify data sources to better understand impacts on diet and health outcomes.