Figure 5-2. Satellite-based navigation and tracking allows more aircraft to fly closely together on more direct routes.  information is more easily accessed. [Figure 5-4]  3. Next generation data communications—current  communications between aircrew and ATC, and  between air traffic controllers, are largely realized  through voice communications. Initially, the  introduction of data communications will provide  an additional means of two-way communication  for ATC clearances, instructions, advisories, flight  crew requests, and reports. With the majority of  aircraft data link equipped, the exchange of routine  controller-pilot messages and clearances via data  link will enable controllers to handle more traffic.  This will improve ATC productivity, enhancing  capacity and safety. [Figure 5-5]  4. Next generation network enabled weather  (NNEW)— seventy percent of NAS delays are  attributed to weather every year. The goal of NNEW  is to cut weather-related delays at least in half. Tens  of thousands of global weather observations and  sensor reports from ground, airborne, and space- based sources will fuse into a single national weather  information system updated in real time. NNEW  will provide a common weather picture across the  NAS and enable better air transportation decision- making. [Figure 5-6]  5. NAS voice switch (NVS)—there are currently  seventeen different voice switching systems in the  NAS; some in use for more than twenty years. NVS  will replace these systems with a single air/ground  2. System wide information management (SWIM)—  will provide a single infrastructure and information  management system to deliver high quality, timely  data to many users and applications. By reducing  the number and types of interfaces and systems,  SWIM will reduce data redundancy and better  facilitate multi- user information sharing. SWIM  will also enable new modes of decision-making as  5-3  ADS-B ground infrastructure is complete and ATC  now uses ADS-B for aircraft tracking both in the air  and on the ground at many airports.  Figure 5-3. Automatic Dependent Surveillance-Broadcast (ADS-B)  systems. 