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 | Advanced Encryption Standard (AES) |
| A symmetric 128-bit block data encryption standard adopted by the U.S. Government in October 2000 to replace the Digital Encryption Standard (DES). |
| | Advanced Mobile Phone System (AMPS) |
| The Advanced Mobile Phone System is one of the earliest commercial cellular systems. AMPS technology is currently deployed throughout North America and AMPS-derivative systems are deployed in a majority of worldwide cellular markets. |
| | Alarm |
| Audible and/or visual signals emitted from an EDE device/system that alerts the operator that a detection of explosive material has been made. |
| | Alarm Indication |
| Audible and/or visual signals that indicate that a metal object has been detected. |
| | Alarm Indicator |
| A device that generates alarm indications. Visual indications can be a light bulb, lamp, light-emitting diode (LED), etc. Audio indicators can be a horn, siren, buzzer, etc. |
| | Alarm Resolution |
| The process by which an EDE operator determines if a threat item is present after receiving an alarm. |
| | Alarm Threshold Setting |
| The minimum signal level above which a Walk-Through Metal Detectors is set to alarm. |
| | Alarm Threshold Setting |
| The minimum signal level above which an EDE device/system is set to alarm. |
| | Altimeter |
| An instrument that shows height above sea level, especially an aneroid barometer used in aircraft that senses pressure changes accompanying changes in altitude. |
| | Angle of View |
| The angular measure of a lens’s Field Of View on the diagonal of the image, expressed in degrees or radians. Vertical and horizontal angles of view are also sometimes stated. |
| | Antenna |
| Any structure or device used to collect or radiate electromagnetic waves. |
| | Aperture |
| A hole, located within the optical path between the front of the lens and the focal plane, which allows light to pass. The size of the aperture determines the depth of field and the time required to adequately expose an image. The size of the aperture is controlled using a multi-leaved adjustable device called a diaphragm or iris. |
| | Application Program Interface (API) |
| The interface (calling conventions) by which an application program accesses an operating system and other services. An API is defined at source code level and provides a level of abstraction between the application and the kernel (or other privileged utilities) to ensure the portability of the code. |
| | As Cellular Device |
| Indicates that the Remote Device portion of a product or service is not vendor-specific and can use a wide variety of cellular devices from a variety of manufacturers. Remote Device capabilities and characteristics are therefore dependent on the make and model of the cellular device chosen by the vendor’s client. |
| | As Cellular Network Communications Range |
| Indicates that the product or service is dependent on the local cellular network for transferring location and status data, and is therefore constrained to the range of the local cellular network. |
| | As GPS Location Accuracy |
| The device or system’s location accuracy is dependent on the accuracy of the Global Positioning System (GPS) and is therefore constrained to the accuracy of GPS as stated in the GPS Standard Positioning Service Performance Standard, dated October 2001. |
| | As Per Radio |
| Indicates that the product or service uses the client’s existing trunked or conventional HF, VHF, UHF, 800 MHz radio network, and handheld/mobile radio units. The capabilities and characteristics of the Remote Device portion of the product or service are therefore dependent on the capabilities and characteristics of the client’s existing handheld/mobile radio units. |
| | Aspect Ratio |
| A numerical expression for the ratio of the image height to the image width. Aspect ratios can be represented as a ratio, such as 4:3, or a number, such as 1.33. |
| | Aspherical Lens |
| A lens with a surface geometry that is not derived from a portion of a spherical surface. Aspherical surfaces are much more complex to calculate and manufacture than spherical surfaces. Using aspheres allows lens designers many more options to design lenses than spherical designs alone. |
| | Attribute |
| A trait, quality, or property describing a geographical feature. A fact describing an entity in a relational data model, equivalent to the column in a relational table. |
| | Autogating |
| An electronic feature that automatically reduces voltages to the micro-channel plate, keeping the image intensifier's brightness within optimal limits, thereby protecting the tube. The effect of this can be seen when one moves from a low-lit area to a brightly lit area. |
| | Automated Video Surveillance (AVS) |
| A technology that uses software to analyze the video image stream. AVS systems may provide object detection, recognition, identification, tracking, and analysis of a variety of surveillance applications. |
| | Automatic Brightness Control (ABC) |
| An electronic feature that automatically reduces voltage to the microchannel plate to keep the image intensifier’s brightness within optimal limits and protect the tube. |
| | Available Repair Parts |
| A determination of whether or not the parts needed for repair of the personnel location system are widely available or available without the need for custom manufacturing. |
| | Backscatter X-Ray |
| Produces images from reflected X- rays. |
