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The REASON instrument makes innovative use of radar sounding, altimetry, reflectometry, plasma and particles analyses. These investigations will use a dual-frequency radar emitting HF (9 MHz) and VHF (60 MHz) with concurrent shallow and deep sounding. [1] [2] [3] Both VHF and HF radiating elements are mounted on a single boom, reducing antenna ...
Two sound mirrors at different positions will generate two different bearings, which allows the use of triangulation to determine a sound source's position. As World War II neared, radar began to become a credible alternative to the sound location of aircraft. For typical aircraft speeds of that time, sound location only gave a few minutes of ...
To measure the distance to an object, the time from transmission of a pulse to reception is measured and converted into a range using the known speed of sound. [28] To measure the bearing , several hydrophones are used, and the set measures the relative arrival time to each, or with an array of hydrophones, by measuring the relative amplitude ...
The fluid core of the Moon was detected from the effects of core/mantle boundary dissipation. [44] The Moon has free physical librations that require one or more stimulating mechanisms. [45] Tidal dissipation in the Moon depends on tidal frequency. [42] The Moon probably has a liquid core of about 20% of the Moon's radius. [11]
A marker beacon is a specialized beacon used in aviation, in conjunction with an instrument landing system (ILS), to give pilots a means to determine distance to the runway. Marker beacons transmit on the dedicated frequency of 75 MHz. This type of beacon is slowly being phased out, and most new ILS installations have no marker beacons.
The ratio between direct sound and reflected sound can give an indication about the distance of the sound source. Loudness: Distant sound sources have a lower loudness than close ones. This aspect can be evaluated especially for well-known sound sources. Sound spectrum: High frequencies are more quickly damped by the air than low frequencies.
Another consideration is the frequency range of the instrumentation. It should be large enough to cover the frequency range of signal interest, taking into account the range of the sensor. To prevent aliasing, many devices come with antialiasing filters, which cut the maximum frequency range of the device to a little less than one-half the ...
Radio wave diffraction is the scattering of radio frequency or lower frequencies from the Earth's ionosphere, resulting in the ability to achieve greater distance radio broadcasting. Sound wave diffraction is the bending of sound waves, as the sound travels around edges of geometric objects. This produces the effect of being able to hear even ...