The Defense Dissemination System electronically disseminate near original quality digital imagery to customers in near real time. The Defense Dissemination System (DDS), which provided the first electronic dissemination of National digital imagery, allowed nuclear warfighting Commanders-in-Chief (CINCs) first ever, near real time, near original quality access to national overhead imagery to assist in rapid targeting and strategic threat assessment. During the Cold War, DDS support to the warfighter was extremely sensitive and classified. In recent years, the secrecy veil has lifted and much of the mystery surrounding this vital warfighting support tool has been lifted.
The three different models of the DDS computer hardware provide intelligence from imagery satellites to thirteen operational locations. DDS is the common access and delivery mechanism for the NIMA Libraries. DDS plans, delivers, operates, and maintains systems for the dissemination of near real-time imagery products to DoD, civil agencies, and foreign customers. The DDS has consistently achieved an operational reliability of 97% to 99% across a world-wide network. The number of operational users of the DDS system grew from the initial four CINCs in 1974 to 26 users of the system at the time NIMA was formed in 1996 to more than 70 users by 1998. The typical Primary Image FAF block distributed through DDS is 17K pixels x 17K pixels [289 Megapixels] at 11 bit/pixel which amounts to 3.33 Gbit uncompressed (417 Megabytes), with typical volumes of 300 Gpixel/day uncompressed and some images running as large as 1.5 Gigapixels.
At the highest level of abstraction, the imagery production process is similar for all types of imagery. Imagery data is collected (e.g., by satellite or airplane) and sent to an initial processor; from this processor the data is sent through a dissemination system to a library or database. The imagery files are copied from the database to an exploitation system where intelligence products are generated; the resulting imagery products are returned to the database. Authorized users can access the images they need from this database. This entire process takes place within SCI enclaves for most types of imagery, even though most imagery is at the Secret Collateral level.
The DDS was formerly managed by the Defense Dissemination Program Office (DDPO), which is now part of of the National Imagery and Mapping Agency. The highly classified Defense Dissemination System used streamlined management techniques with minimum staff involvement due to the security constraints of this minimum exposure program. Air Force Space and Missile Systems Center was responsible for DDS Acquisition Logistics, which includes everything involved in acquiring logistics support equipment and personnel for a new weapons system, with responsibilities for systematically identifying, defining, designing, developing, producing, acquiring, delivering, installing, and upgrading logistics support capability requirements through the acquisition process for systems, subsystems, and equipment.
DDS-I Adaptive image compression technology made the electronic dissemination of high resolution digital imagery feasible with little noticeable degradation to the human eye. This first generation system compressed 11-bit per pixel images into an average of 2-bits per pixel. The state of the art DDS I/II Laser Beam Recorder (LBR) was developed by DDPO in less than three years. Compared to similar systems developed within the national community, the LBR was designed, developed, and produced for 1/10 the cost and could be operated and maintained by Air Force enlisted technicians rather than electrical engineers and image scientists. The LBR was the first device that allowed worldwide tactical users to obtain digital imagery in a timely fashion for exploitation and archival. Its fast writing speed enabled contiguous image segments to be recorded on roll film without a break eliminating the need for large buffers. Capable of printing at 3 Megapixels per second with 11 bits of dynamic range and over 2000 dots per inch of resolution, its performance still exceeds that of today's most sophisticated laser printers. DDS-II DDPO successfully fielded four generations of the Defense Dissemination System, and the DDS-II was a direct evolution from the initial DDS-I. DDS-III The third-generation Defense Dissemination System [DDS III] was implemented in the mid-1980s. DDS III included the ability to transmit compressed imagery through military and commercial satellite and terrestrial dedicated lines. The DDS III Receive Locations were the first transportable Near Real Time/Near original Quality (NRT/NOQ) electronic digital imagery dissemination systems for the Army. The DDS third generation system implemented an improved 1.29 bits per pixel (average) two dimensional Discrete Cosine Transform (DCT) continuous tone still imagery compression algorithm. DDS III used highly specialized computer hardware to achieve an amazing processing throughput of 10.5 Megabits/second to both hardcopy and softcopy exploitation systems. DDS III also provided the ability to duplicate and enlarge PERM images onto normal processed film and print materials. DDS-IV This was the first ever intelligence system source selection that included an operational capability demonstration hooked to a "live" national system. DDS IV successfully pioneered electronic source selection, Single Acquisition Master Plan, reduced military standards, and emphasized past performance evaluation techniques for the intelligence community as part of the Air Force's Acquisition Lightning Bolt Initiatives. Its first unit, called a Dissemination Element (DE), was delivered less than one year after contract award--providing operational imagery in support of the Peruvian hostage crisis.
The Defense Dissemination Program Office was the first major intelligence program to demonstrate and implement Asynchronous Transfer Mode (ATM) on communications links. The Defense Dissemination System routes imagery through the DISN ATM (DATM) switch at Ft. Belvoir, operated by DISA. From the ATM switch, the intelligence products are disseminated via systems such as the Defense Satellite Communication System. The DATM switch has a record of poor performance, the Defense Dissemination System has experienced chronic problems with this switch. On 27 December 1999 problems with the DDS ATM switch produced outages of 12 hours or more for Pacific Command and Central Command. The original decision to use ATM was controversial, with Aerospace Corporation analysts specifically pointing to problems with it in this application. NIMA management nonetheless chose to pursue what some regarded as a technology which had been documented as improper, inappropriate and a waste of Government funds.