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Tactical Common Data Link
Common Data Link (CDL) is a secure U.S. military communication protocol. It was established by the U.S. Department of Defense in 1991 as the military's primary protocol for imagery and signals intelligence. CDL operates within the at data rates up to 274 Mbit/s. CDL allows for full duplex data exchange. CDL signals are transmitted, received, synchronized, routed, and simulated by Common data link (CDL) Interface Boxes (CIBs). The FY06 Authorization Act (Public Law ) requires use of CDL for all imagery, unless waiver is granted. The primary reason waivers are granted is from the inability to carry the 300 pound radios on a small (30 pound) aircraft. Emerging technology expects to field a 2-pound version by the end of the decade (2010). The Tactical Common Data Link (TCDL) is a secure data link being developed by the U.S. military to send secure data and streaming video links from airborne platforms to ground stations. The TCDL can accept data from many different sourc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communication Protocol
A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics (computer science), semantics and synchronization of communication and possible Error detection and correction, error recovery methods. Protocols may be implemented by Computer hardware, hardware, software, or a combination of both. Communicating systems use well-defined formats for exchanging various messages. Each message has an exact meaning intended to elicit a response from a range of possible responses pre-determined for that particular situation. The specified behavior is typically independent of how it is to be Implementation, implemented. Communication protocols have to be agreed upon by the parties involved. To reach an agreement, a protocol may be developed into a technical standard. A programming language describes the same for computations, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Image
An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensional picture, that resembles a subject. In the context of signal processing, an image is a distributed amplitude of color(s). In optics, the term “image” may refer specifically to a 2D image. An image does not have to use the entire visual system to be a visual representation. A popular example of this is of a greyscale image, which uses the visual system's sensitivity to brightness across all wavelengths, without taking into account different colors. A black and white visual representation of something is still an image, even though it does not make full use of the visual system's capabilities. Images are typically still, but in some cases can be moving or animated. Characteristics Images may be two or three-dimensional, such as a ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signals Intelligence
Signals intelligence (SIGINT) is intelligence-gathering by interception of ''signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly used in communication (electronic intelligence—abbreviated to ELINT). Signals intelligence is a subset of intelligence collection management. As classified and sensitive information is usually encrypted, signals intelligence in turn involves the use of cryptanalysis to decipher the messages. Traffic analysis—the study of who is signaling whom and in what quantity—is also used to integrate information again. History Origins Electronic interceptions appeared as early as 1900, during the Boer War of 1899–1902. The British Royal Navy had installed wireless sets produced by Marconi on board their ships in the late 1890s, and the British Army used some limited wireless signalling. The Boers captured some wireless sets and used them to make vital transmis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Full Duplex
A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow for simultaneous communication in both directions between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field. There are two types of duplex communication systems: full-duplex (FDX) and half-duplex (HDX). In a full-duplex system, both parties can communicate with each other simultaneously. An example of a full-duplex device is plain old telephone service; the parties at both ends of a call can speak and be heard by the other party simultaneously. The earphone reproduces the speech of the remote party as the microphone transmits the speech of the local party. There is a two-way communication channel between them, or more strictly speaking, there are two communication channel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encrypt
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decipher a ciphertext back to plaintext and access the original information. Encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor. For technical reasons, an encryption scheme usually uses a pseudo-random A pseudorandom sequence of numbers is one that appears to be statistically random, despite having been produced by a completely deterministic and repeatable process. Background The generation of random numbers has many uses, such as for rando ... encryption Key (cryptography), key generated by an algorithm. It is possible to decrypt the message without possessing the key but, for a well-designed encryption scheme, considerable computational resources and skills are required. An au ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiplexing
In telecommunications and computer networking, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource - a physical transmission medium. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910. The multiplexed signal is transmitted over a communication channel such as a cable. The multiplexing divides the capacity of the communication channel into several logical channels, one for each message signal or data stream to be transferred. A reverse process, known as demultiplexing, extracts the original channels on the receiver end. A device that performs the multiplexing is called a multiplexer (MUX), and a dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Code
In communications and information processing, code is a system of rules to convert information—such as a letter, word, sound, image, or gesture—into another form, sometimes shortened or secret, for communication through a communication channel or storage in a storage medium. An early example is an invention of language, which enabled a person, through speech, to communicate what they thought, saw, heard, or felt to others. But speech limits the range of communication to the distance a voice can carry and limits the audience to those present when the speech is uttered. The invention of writing, which converted spoken language into visual symbols, extended the range of communication across space and time. The process of encoding converts information from a source into symbols for communication or storage. Decoding is the reverse process, converting code symbols back into a form that the recipient understands, such as English or/and Spanish. One reason for coding is to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmit
Transmit is a file transfer client program for macOS. Developed by Panic, Transmit is shareware. After a seven-day trial period, the product can only be used for seven-minute sessions until it has been purchased. Originally built as an FTP client, it now supports a number of protocols ranging from the more traditional ones like SFTP and WebDAV to cloud services like Google Drive and Dropbox. Transmit 4 includes a number of features, many of which take advantage of technologies Apple introduced in OS X 10.4, such as uploading using a Dashboard (macOS), Dashboard widget or the dock, support for .Mac and iDisk/WebDAV, FTP/WebDAV/S3 servers as disks in Finder (since v4.0), Spotlight, Droplets, Amazon S3 support and Automator plugins. The app was called "Transit" at introduction in 1998, but had to be changed due to a conflict with an existing product. Transmit was originally developed for Classic Mac OS, but that version has been discontinued and made freeware. Transmit for iOS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ku Band
The Ku band () is the portion of the electromagnetic spectrum in the microwave range of frequencies from 12 to 18 gigahertz (GHz). The symbol is short for "K-under" (originally german: Kurz-unten), because it is the lower part of the original NATO K band, which was split into three bands (Ku, K, and Ka) because of the presence of the atmospheric water vapor resonance peak at 22.24 GHz, (1.35 cm) which made the center unusable for long range transmission. In radar applications, it ranges from 12 to 18 GHz according to the formal definition of radar frequency band nomenclature in IEEE Standard 521–2002. Ku band is primarily used for satellite communications, most notably the downlink used by direct broadcast satellites to broadcast satellite television, and for specific applications such as NASA's Tracking Data Relay Satellite used for International Space Station (ISS) communications and SpaceX Starlink satellites. Ku band satellites are also used for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MQ-8B Fire Scout
The Northrop Grumman MQ-8 Fire Scout is an unmanned autonomous helicopter developed by Northrop Grumman for use by the United States Armed Forces. The Fire Scout is designed to provide reconnaissance, situational awareness, aerial fire support and precision targeting support for ground, air and sea forces. The initial RQ-8A version was based on the Schweizer 330, while the enhanced MQ-8B was derived from the Schweizer 333. The larger MQ-8C Fire Scout variant is based on the Bell 407. As of February 2018, 23 MQ-8B variants were in service with the U.S. Navy. Design and development RQ-8A As the US Navy was withdrawing its RQ-2 Pioneers from service, it began to seek a second generation UAV. The Navy requirement specified a vertical takeoff & landing (VTOL) aircraft, with a payload capacity of 90 kg (200 lb), a range of 125 miles (200 km), an endurance on station of three hours at an altitude of , and the ability to land on a ship in a wind. The UAV was to fly 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bit Error Rate
In digital transmission, the number of bit errors is the number of received bits of a data stream over a communication channel that have been altered due to noise, interference, distortion or bit synchronization errors. The bit error rate (BER) is the number of bit errors per unit time. The bit error ratio (also BER) is the number of bit errors divided by the total number of transferred bits during a studied time interval. Bit error ratio is a unitless performance measure, often expressed as a percentage. The bit error probability ''pe'' is the expected value of the bit error ratio. The bit error ratio can be considered as an approximate estimate of the bit error probability. This estimate is accurate for a long time interval and a high number of bit errors. Example As an example, assume this transmitted bit sequence: 1 1 0 0 0 1 0 1 1 and the following received bit sequence: 0 1 0 1 0 1 0 0 1, The number of bit errors (the underlined bits) is, in this case, 3. The BER is 3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
