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Trajectory Planning in Autonomous Vehicles using GPS and Digital Compass
Published in P. C. Thomas, Vishal John Mathai, Geevarghese Titus, Emerging Technologies for Sustainability, 2020
This system best works when there is 5-6 satellite connection, as the accuracy of the position is increased to a great extent, preferably operated outdoors with clear sky. The GPS receiver tends to have a lag in data stream; usually data comes at 1Hz, better to have a faster stream of data (> 5Hz). If a single core/thread controller is used the vehicle will turn out to have a slower response or reaction time. The magnetic field of the Earth is not a constant; it changes from time to time and also from place to place. The phenomenon is known as magnetic declination or magnetic variation. This results in an angle between the magnetic north (direction of the north pole of a magnetized compass needle, corresponding to the direction of the Earth’s magnetic field lines) and the true north (direction along meridian towards the geographic North Pole). This angle varies depending on the position on the earth’s surface and changes over time.
Other Techniques
Published in C. R. Kitchin, Astrophysical Techniques, 2020
The declination of an object, δ, is its angular distance north or south of the equator. The right ascension, α, is its angular distance around from the meridian (or great circle) that passes through the vernal equinox and the poles, measured in the same direction as the solar motion (Figure 5.2). By convention, declination is measured from −90° to + 90° in degrees, arc-minutes and arcseconds and is positive to the north of the equator and negative to the south. Right ascension is measured from 0° to 360°, in units of hours, minutes and seconds of time where, at the equator, () 1 hour=15° () 1 minute=15′ () 1 second=15″
Physics of the Globe
Published in Aurèle Parriaux, Geology, 2018
At all points on the Earth’s surface, the magnetic field is defined by its intensity and two angles (Fig. 4.57): Declination (D): the angle between the projection of the magnetic field vector on the local horizon at the given point and the geographical meridian passing though this point. This angle is low for points that are far from polar regions. As one approaches the poles, the declination values increase, and it is not as easy to locate oneself with a compass (Fig. 4.58). Over time, the magnetic poles move slightly, although they remain in more or less the same region. The declination values thus vary slightly. For example, in Switzerland, the declination was zero in 1994. Since that time, it has changed about 10 minutes of an angle per year. On topographic maps the declination is generally indicated for a given date. This declination is used for adjusting the compass to the work area.Inclination (I): this is the angle between the magnetic field vector and the horizon of the place of interest. It can be seen on figure 4.56 that it is strongly linked to the magnetic latitude L of the point. An approximate relationship between these two factors has been established: (
Optimisation of heliostat field layout for solar power tower systems using iterative artificial bee colony algorithm: a review and case study
Published in International Journal of Ambient Energy, 2021
Toufik Arrif, Adel Benchabane, Mawloud Germoui, Badreddine Bezza, Abdelfettah Belaid
The solar hour angle (radians) can be defined as The zenith angle is the angle between the sunrays’ incidence vector and the vertical or zenith plan, the zenith angle is given as follows: Δ is the solar declination angle; Φ is the location latitude and ω is the hour angle. Since and are interrelated angles, they can be expressed as The azimuthal solar angle is illustrated in Figure 1, and estimated by Equation (7):
Construction of sundials via vectors
Published in International Journal of Mathematical Education in Science and Technology, 2019
The angle φ in Figure 1 is the latitude and d the declination of the Sun (angular distance from the celestial equator). The angle d varies with the inclination of the axis of the Earth, between approximately to during one year. Since the distance from the Sun to the Earth is large, light rays from the Sun striking the Earth can be assumed to be parallel (illustrated by the lines and ). The style in Figure 1 is oriented in the north–south direction pointing towards north with an angle φ to the horizontal plane (this plane is tangent to the sphere at the point B). The reader is encouraged to show that the angle BDC equals φ implying (use alternate angles) that the style is parallel to the axis of the Earth, and that the height of the Sun, ABE, is . The reader is also advised to think through the construction when the latitude satisfies . We work on the northern hemisphere and assume hereafter that the latitude is greater than .
Broadband dependence of atmospheric transmissions in the UV and total solar radiation
Published in Tellus B: Chemical and Physical Meteorology, 2019
Hana Lee, Woogyung Kim, Yun G. Lee, Ja-Ho Koo, Yeonjin Jung, Sang S. Park, Hi-Ku Cho, Jhoon Kim
In this study, we calculated the daily total transmission using the 9-year time series of measurements. First, we obtained a daily slant transmission (T′) from daily representative measurements. Second, we converted this slant-column value to the total-column transmission using Z. Local noon time, which corresponds to the highest solar elevation Z0, is taken as the standard time for this conversion process. The relation between the slant transmission (T′) and the zenith transmission (T) is where m refers to the relative optical air mass (≈ sec Z0), and cos (Z0) can be expressed using various geometrical factors as, where , , and are the hour angle, the latitude, and the solar declination, respectively (e.g. Iqbal, 1983). As a result, the daily m is obtained at local noon ( = 0) in this study. Then finally, atmospheric transmission is represented in the zenith direction (i.e. T = T′1/m) and, hereafter, we use this definition of atmospheric transmission.