Anti-Spoofing
For the NAVSTAR system, anti-spoofing is the process whereby the P code used for the precise positioning service is encrypted. The resulting encrypted code is called the Y code. The encryption data can only be decoded by GIPS receivers with special decryption circuitry, guarding against fake transmissions of satellite data.
Applicant
A person who applies for an ab initio training vacancy.

Application Software providing a service to its Users, in the guise of a consistent set of functionalities. The ARTAS software (implemented in each ARTAS Unit) is an application. Application Control Service Element The association control service element establishes, maintains and releases associations between application entities. Application Entity Part of an application process which is concerned with communications within the OSI environment. The aspects of an application process which need to be taken into account for the purposes of OSI are represented by one or more AEs. Application Form Form to be filled in when applying for ab initio training. Application Layer The layer of the OSI reference model that controls application user access to the communication system. Application Process A set of resources, including processing resources, within a real open system that may be used to perform a particular information processing activity. Application Service Element A set of functions that provide OSI communications capabilities for the inter-working of AEs for a specific purpose. An AE may be composed of one ASE or several ASEs of different types. Application Specific Integrated Circuit A gate array or other non-standard chip design for proprietary use. Gate array. A special type of chip that starts out as a non specific collection of logic gates. Late in the manufacturing process, a layer is added to connect the gates for a specific function. By changing the pattern of connections, the manufacturer can make the chip suitable for many needs. After the chip has been configured to meet a specific need, it becomes an ASIC. Approach Control 1- Unit charged with control of traffic around one or more airports and responsible for the spacing of traffic on final approach. Approach control, that part of ATC that is concerned with departing and arriving aircraft. Arriving aircraft are transferred from ACC via APP to tower control, departing aircraft are transferred from tower control via APP to ACC.