Search results
Results from the WOW.Com Content Network
A reference antenna is an antenna with known performance. It is normally used to calibrate other systems. It is normally used to calibrate other systems. During a relative calibration, an antenna's phase center offset (PCO) and phase center variations (PCV) are computed with respect to the reference antenna which is normally assigned zero PCV ...
The datum may be accessed via NGS's network of survey marks or through the Continuously Operating Reference Station (CORS) network of GPS reference antennas. NGS is responsible for computing the relationship between NAD83 and the ITRF. The physical components of the NSRS are reflected in its height system, defined by the vertical datum NAVD88.
The new reference frames will rely primarily on GNSS, such as the Global Positioning System (GPS), as well as on a gravimetric geoid model resulting from NGS' Gravity for the Redefinition of the American Vertical Datum Project. These new reference frames are intended be easier to access and to maintain than NAD 83 and NAVD 88, which rely on ...
Electronic distance measurement (EDM) was introduced around 1960, when the prototype instruments became small enough to be used in the field. Instead of using only sparse and much less accurate distance measurements some control networks were established or updated by using trilateration more accurate distance measurements than was previously possible and no angle measurements.
The ILS system is composed of 180 different transmitting antennas at each point built. For some time the FAA and NASA developed a much improved system, the microwave landing system (MLS). The entire MLS system for a particular approach was isolated in one or two boxes located beside the runway, dramatically reducing the cost of implementation.
For long delay multipath, the receiver itself can recognize the wayward signal and discard it. To address shorter delay multipath from the signal reflecting off the ground, specialized antennas (e.g., a choke ring antenna) may be used to reduce the signal power as received by the antenna. Short delay reflections are harder to filter out because ...
PACS and SACS are designated by the National Geodetic Survey and must meet the specific siting, construction, and accuracy requirements. (also see airport security) PACS coordinates are established by meeting a survey, data processing, adjustment and reporting standard known as the NGS Bluebook. (See Aviation safety for more info)
The Antenna Interface Standards Group (commonly referred to as AISG) is a non-profit international consortium formed by collaboration between communication infrastructure manufacturers and network operators with the purpose of maintaining and developing a standard for digital remote control and monitoring of antenna line devices in the wireless industry. [1]