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If a fast time to first fix (TTFF) is needed, it is possible to upload a valid ephemeris to a receiver, and in addition to setting the time, a position fix can be obtained in under ten seconds. It is feasible to put such ephemeris data on the web so it can be loaded into mobile GPS devices. [ 6 ]
A diagram of a typical nautical sextant, a tool used in celestial navigation to measure the angle between two objects viewed by means of its optical sight. Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space or on the ...
Time to first fix (TTFF) is a measure of the time required for a GPS navigation device to acquire satellite signals and navigation data, and calculate a position solution (called a fix). An animation depicting the orbits of GPS satellites in medium Earth orbit
In mathematics, a fixed point (sometimes shortened to fixpoint), also known as an invariant point, is a value that does not change under a given transformation. Specifically, for functions, a fixed point is an element that is mapped to itself by the function. Any set of fixed points of a transformation is also an invariant set.
Due to the relative geometry of any given satellite to a receiver, the precision in the pseudorange of the satellite translates to a corresponding component in each of the four dimensions of position measured by the receiver (i.e., , , , and ). The precision of multiple satellites in view of a receiver combine according to the relative position ...
A position circle is a circle that can be measured both from a chart and from the surface of the earth for the purpose of position fixing. For the purposes of land or coastal navigation, a position circle can be generated by making a horizontal angle measurement between two landmarks using a sextant .
Position resection and intersection are methods for determining an unknown geographic position (position finding) by measuring angles with respect to known positions.In resection, the one point with unknown coordinates is occupied and sightings are taken to the known points; in intersection, the two points with known coordinates are occupied and sightings are taken to the unknown point.
In geometry and kinematics, coordinate systems are used to describe the (linear) position of points and the angular position of axes, planes, and rigid bodies. [16] In the latter case, the orientation of a second (typically referred to as "local") coordinate system, fixed to the node, is defined based on the first (typically referred to as ...