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Electronic Position Fixing Systems
Published in Graham D. Lees, William G. Williamson, Handbook for Marine Radio Communication, 2020
Graham D. Lees, William G. Williamson
The Global Positioning System (GPS) is also known as ‘Navstar’ and is operated by the US Department of Defense (DoD). GPS provides a worldwide continuous positional fix capability, with a constellation of satellites at altitudes of approximately 20,000 km providing two-dimensional fixes (latitude and longitude) for marine users, and three-dimensional fixes (latitude, longitude and altitude) for aeronautical, survey users, etc. As part of an upgrading exercise, there are now 27 operational satellites in the GPS constellation, improving precision of GPS receiver calculations compared to the original number of 24. This increased number gives a non-uniform arrangement that improves reliability and availability, particularly if multiple satellites go out of service. Usually, nine satellites are visible from any point on the ground at any one time, giving redundancy over the minimum four satellites needed for a position.
UAS Applications
Published in R. Kurt Barnhart, Douglas M. Marshall, Eric J. Shappee, Introduction to Unmanned Aircraft Systems, 2021
Aerial surveying is often confused with aerial mapping, and sometimes, the terms are used interchangeably. However, the term “surveying” is differentiated from mapping by the reference to measurement of physical characteristics. ESRI (2015) defines surveying as “measuring physical or geometric characteristics of the earth. Surveys are often classified by the type of data studied or by the instruments or methods used. Examples include geodetic, geologic, topographic, hydrographic, land, geophysical, soil, mine, and engineering surveys.” Many aerial surveys begin with an aerial map of an area of interest, but the process of surveying implies that characteristics are being measured beyond simple aerial imagery.
UAS Applications
Published in Douglas M. Marshall, R. Kurt Barnhart, Eric Shappee, Michael Most, Introduction to Unmanned Aircraft Systems, 2016
Aerial surveying is often confused with aerial mapping and sometimes the terms are used interchangeably. However, the term “surveying” is differentiated from mapping by the reference to measurement of physical characteristics. Specifically, Esri (2015) defines surveying as “measuring physical or geometric characteristics of the earth. Surveys are often classified by the type of data studied or by the instruments or methods used. Examples include geodetic, geologic, topographic, hydrographic, land, geophysical, soil, mine, and engineering surveys.” Many aerial surveys begin with an aerial map of an area of interest, but the process of surveying implies that characteristics are being measured beyond simple aerial imagery.
Considerations for using historical geoscientific information in mineral resource estimation
Published in CIM Journal, 2022
R. Pressacco, L. Evans, W. E. Roscoe
Historical drill-hole information can exist in the form of physical drill logs containing records of drill-hole location, down-hole trajectories, lithologies, structural data, and assays (Figures 1 and 2). Historical drill-hole information can also exist as digital files that are stored on various media and in various data formats and file types. Physical forms of historical data include such materials as diamond drill core (Figure 3) or sample materials (Figures 4 and 5) that were collected by previous owners of a mineral property. In many cases, despite the age of the historical data, they remain valid, are often of great utility for the preparation of a mineral resource estimate, and can provide significant time and cost savings. However, the degree of confidence of the historical data can vary from one source to another or with time. In these cases, QPs may consider assigning a level of confidence to the historical data, which can subsequently be considered when preparing a mineral resource estimate. For example, the collar locations of drill holes and their elevations may have been determined by various methods of measurements with differing degrees of accuracies during successive drilling programs. These include pace-and-compass, cloth tape and compass, optical surveying methods (theodolites or total stations), handheld GPS (global positioning system) units, or survey-grade GPS units. Each of these methods will have varying degrees of accuracy to which confidence or quality factors can be assigned.