III. Federal Use of the 1755-1850 MHz Band
Nationally, the 1755-1850 MHz band is allocated on a exclusive basis to the Federal Government for fixed and mobile. Footnote G42 to the National Table of Frequency Allocations provides for the co-equal accommodation of Federal space command, control, and range and range-rate systems for earth station transmission in the 1761-1842 MHz band. The band supports several Federal functions; (1) tracking and control for DOD space systems, (2) medium-capacity, conventional fixed microwave communications systems, (3) military tactical radio relay radios, (4) air combat training systems, (5) precision guided munitions, (6) high resolution video data links, and various other aeronautical mobile applications, and 7) land mobile video functions such as robotics, surveillance, etc. The radio systems supporting these functions are located across the United States. Figure 1 is a pictorial representation of the functions of major Federal systems supported in the 1710-1850 MHz band.
Fixed microwave networks in the 1755-1850 MHz band support backbone communications systems for many of the Federal agencies. Fixed links are operated by Federal agencies for voice, data, and/or video communications where commercial service is unavailable, excessively expensive, or unable to meet required reliability. Applications include law enforcement, emergency preparedness, support for the national air space system, military command and control networks, and control links for various power, land, water, and electric-power management systems. Other fixed links include data relay, timing distribution signals, video relay, video surveillance systems, and robot video systems for hazardous material response in support of explosive and forensic investigations.
As an example of fixed systems, the U.S. Army Corps of Engineers uses this band extensively for its fixed microwave radio systems serving backbone communications for the engineering districts in the continental United States. The Corps also uses this frequency band for various purposes such as operating remotely-controlled hydro-electric generating stations; providing communications support for emergency civilian relief, flood control and sensor telemetry; temporary communications in each district; and maintenance and traffic control of approximately 48,000 kilometers of inland waterways, traffic movement, harbors, locks, and dams.
Transportable radio relay systems are used by the military for nodal communications stations that support tactical communications for a wide area. The most common system is called the Mobile Subscriber Equipment (MSE). This system is used extensively in the United States by warfighters to establish tactical communications supporting command and control for wide-area networks. Several thousand tactical radio relay systems are in the military inventory and used at many military establishments throughout the country. The propagation characteristics of the band permit excellent tactical nodal connectivity. Radio relay systems link various subordinate, lateral and strategic headquarters, functional and component nodes, into an integrated area-wide network. Congestion and use of the band are heavy in proximity to military bases and training areas. Naval task forces use a variant of this system known as the Digital Wideband Transmission System (DWTS) which is a surface-based, point-to-point communications, and mobile system that is used at several Naval facilities. This system has approximately 600 units in the field.
One of the most difficult training missions is the training of air combat crews. Current air combat training involves actual air-to-air encounters, with a network of ground stations monitoring the training activity. Information regarding the aircraft's flight parameters are relayed to ground stations, and other information is sent to the aircraft from the ground stations. Several systems are in use by the military services, and are variations of the Air Combat Training Systems (ACTS). These systems currently operate in the 1755-1850 MHz band, and new systems will be coming on line soon.
Additionally, the Federal law enforcement agencies use this band to employ undercover low-power video surveillance devices during criminal investigations. These devices may be authorized throughout the US&P for both protective operations and criminal investigations. The video footage obtained during these investigations is critical for providing rapid response support to undercover officers and agents, and is used as evidence during criminal trials and procedures.
There are 4,869 assignments for Federal stations in the 1755-1850 MHz band listed in the GMF as of September, 2000. The GMF is the Federal Government's master list of frequency assignments authorized by NTIA, but does not represent the number of equipments associated with each assignment. There may be many pieces of radio equipment operating under a single frequency assignment. Further, some assignments may be for nation-wide use. The average growth of new assignments in the 1755-1850 MHz band is about 300 assignments per year. The majority of these assignments are in the fixed service (80 percent), followed by mobile, space, land mobile, and aeronautical-mobile services. The five categories of radio services (plus experimental stations) support the four main functions that are carried out in this band. Presently, 25 Federal entities are authorized to operate in the 1755-1850 MHz band. The major users are: Army, Air Force, Navy, U.S. Department of Agriculture (USDA), the Department of Energy (DOE), the Department of Justice (DOJ), the Federal Aviation Administration (FAA), and the Department of the Interior (DOI). Table 6 shows the GMF summary count of station classes per agency and service in the subject band as of September 2000. A plot of the location of these assignments is shown in Figure 2.
Number of Frequency Assignments
in the 1755-1850 MHz Band
|Mobile Service||Aeronautical Mobile Service||Land Mobile Service||Space Services||Experimental|
1. Ten assignments fall into radio services not shown in the table. For example, telemetry for special projects.
2. The fixed service category includes a number of assignments that are employed by the military services for transportable equipment.
Satellite Control Systems
Introduction. Satellites orbit the Earth in either geosynchronous orbits (GSO) or non- geosynchronous orbits (NGSO). Satellites operated by the DOD include both GSO and NGSO, and are used for such functions as communications, navigation, surveillance, missile early warning and attack characterization, weather monitoring, and research and development. The criticality of the Satellite Control Network (SCN) functions is such that DOD satellites can neither be launched or operated without the SCN. These satellites must be supported by the SCN to achieve proper orbit, be initialized for operations, maintain orbit and configuration, perform emergency recovery operations following on-orbit failures, and for disposal operations at end-of-life. Generally, satellites can be controlled to maintain proper orbit, and must be commanded to perform certain functions. This is the control function. The satellite controller must know the location of the satellite to determine the present orbit. This is called a tracking function. The operators also need to know the "health" of the satellites, so a telemetry link sends back to the ground station information relating to the status of the electrical systems onboard the satellite. This is the telemetry function. The combination of these functions for satellite control is termed TT&C. The uplink TT&C function is performed in the 1755-1850 MHz band for military satellites. The associated downlink for these satellites is in the 2200-2290 MHz band.
Tracking, Telemetry, and Command. The 1761-1842 MHz band segment supports the TT&C for the DOD satellites, in addition to the North Atlantic Treaty Organization (NATO) and British military satellites, and various space and ballistic missile test programs. TT&C supports automatic space vehicle acquisition and tracking, ranging, reception and recording of vehicle telemetry data, and transmissions of commands to the space vehicle.
The TT&C subsystem monitors and controls all of the other systems on the spacecraft, transmits the status of those systems to the control segment on the ground, and receives and processes instructions from the control segment. Telemetry components include sensors throughout the satellite to determine the status of various components, transmitters and antennas to provide the data to the control segment, and even the data itself.(1) The SCN is critical to launch and early orbit functions for virtually all U.S. satellites and emergency recovery for most U.S. government satellites.
Telemetry also includes data on the operation and status of the satellite's payload. For example, on a communications satellite, telemetry would include data on power output of transponders, pointing direction of antennas, and antenna and transponder switch configurations. Tracking involves determining a satellite's position, altitude and other orbital parameters. Many satellites carry a beacon which transmits a signal to help ground tracking receivers locate the satellite. On-board sensors, such as star trackers, horizon scanners and inertial navigation sensors provide other tracking data. Tracking information is essential to determine a satellite's orbital parameters so that accurate predictions can be made of where the satellite will be in the future. In this way, the satellite's orbit can be adjusted so that it will be where it is supposed to be when it is supposed to be there.
Commanding is the act of controlling a satellite. Commanding a satellite is accomplished by sending signals to it which initiate an action or change the configuration in some way. Commands may be executed by the satellite immediately upon receipt, or stored for later execution. Some commands are part of onboard software that allows the satellite to execute certain functions autonomously when a predefined condition exists. Commands may direct the thrusters to fire to change the orbit, or may reconfigure the payload to meet the needs of users.
The major system operating in this band segment that supports the TT&C functions is the Air Force Space Ground Link Subsystem (SGLS). The band plan for SGLS comprises 20 discrete frequencies within the 1761-1842 MHz band segment beginning at 1763.721 MHz and ending with 1839.795 MHz. Each channel is 4.004 MHz wide. Although most TT&C operations are provided by fixed sites, the Air Force also uses transportable SGLS-compatible earth stations to provide additional coverage during launches, early orbit operations, anomaly resolution, and critical orbit insertion maneuvers. These transportable stations are moved as necessary to accomplish the mission. The NTIA, in its Final Reallocation Report, noted that Air Force maintained that it is not possible to change the frequencies for satellites which have already been launched, and while it may be possible to change the frequency of satellites which have yet to be launched, in the near term this would be extremely expensive.(2)
In addition to supporting TT&C for military satellites, the 1761-1842 MHz band segment supports TT&C for the cooperative DOE/DOD Proliferation Detection Technology (PDT) Program. The PDT Program will demonstrate advanced system technologies for remotely monitoring nuclear facilities and for identifying and characterizing undeclared and clandestine nuclear facilities. Although this program is directed at nuclear proliferation monitoring, the technology could potentially serve a variety of other national security and civilian needs.(3)
The operation of U.S. satellite control facilities internationally, is authorized by specific host nation agreements in those countries in which the SGLS-compatible stations are deployed. The lack of spectrum support for continued satellite control operations in the 1755-1850 MHz band would have implications for U.S. allies as well, since both NATO and the UK depend on satellite control stations operating in the 1755-1850 MHz band to provide military spacecraft TT&C support for the NATO SATCOM IV and the UK SKYNET satellites, respectively.
Air Force Satellite Control Network. The Air Force is the designated service responsible for platform control of most DOD satellites. The organizations and facilities involved are organized into the AFSCN. The principal organization in the AFSCN is the 50th Space Wing of the Air Force Space Command, with headquarters at Schriever Air Force Base, Colorado.
The AFSCN provides support for the operation, control and maintenance of a variety of DOD and some non-DOD satellites. This involves continual execution of the tasks involved in TT&C. In addition, the AFSCN provides prelaunch simulation, launch support and early orbit support while satellites are in initial or transfer orbits and require maneuvering to their final orbit. The AFSCN provides tracking data to help maintain the catalog of space objects and distributes various data such as satellite ephemeris, almanacs, and other information.
The AFSCN consists of satellite control centers, tracking stations and test facilities located around the world. Satellite Operations Centers are located at Schriever Air Force Base near Colorado Springs, Colorado and Onizuka Air Force Base, Sunnyvale, California. These centers are manned around the clock and are responsible for the command and control of their assigned satellite systems. The control centers are linked to remote tracking stations (RTS's) around the world. The RTS's provide the link between the satellite being controlled and the control center. A similar relationship exists for dedicated networks. RTS's around the world are needed to maintain frequent communications with the satellite. Without RTS's, the control centers would only be able to contact a satellite when it came into the control center's view. Some satellites, especially those in geostationary orbit, never come within view of their control center (most control centers do not have antenna capabilities to communicate directly with satellites in this band). Space vehicle checkout facilities are used to test launch vehicles and satellite platforms to ensure that the onboard systems operate within specifications.
Remote Tracking Stations. Each RTS performs essential mission operations on a 24 hours/day, 7 days/week basis (normally approximately 400 satellite contacts/day). The operations are driven by the requirements to support U.S. national security space operations, as well as by NATO, UK, and NASA. Each RTS has one to three antennas transmitting in the 1755-1850 MHz band. On the occasion of major maintenance or antenna replacement, transportable assets are deployed to the RTS sites to continue operations. The antennas used are typically 60, 44, and 33 feet in diameter. They are supported by transmitters operating between 250 and 7000 watts, depending on the required mission operation. Filters are employed to limit out-of-band radiation. The antennas may be pointed low on the horizon to communicate with low-altitude satellites which have very short visibility times. Low-angle radiation will also occur at Vandenberg AFB, California and Cape Canaveral AFS, Florida to conduct open loop check-out of satellites on launch pads and to verify communications links prior to launch. For other satellite contacts, the antennas are typically pointed at higher elevation angles. The infrastructure at each RTS has evolved over the last 34-40 years and is extensive and sophisticated with regard to facility power, emergency power and connectivity to commercial terrestrial communications. For the most part, the RTS's are located on U.S. military or host nation military/government facilities. RTS's are located as follows:
1. Vandenberg Tracking Station, Vandenberg AFB, California.
2. New Hampshire Tracking Station, New Boston Air Station, New Hampshire.
3. Thule Tracking Station, Thule Air Base, Greenland.
4. Guam Tracking Station, Andersen AFB, Guam.
5. Hawaii Tracking Station, Kaena Point, Oahu, Hawaii.
6. Colorado Tracking Station, Schriever AFB, Colorado.
7. Oakhanger Telemetry and Command Station, Borden, Hampshire, England.
8. Diego Garcia Tracking Station, British Indian Ocean Territory, Diego Garcia.
9. Camp Parks Communications Annex, Pleasanton, California
10. Eastern Vehicle Checkout Facility, Cape Canaveral AFS, Florida.
11. Onizuka AFS, California
The AFSCN sites at Vandenberg, Thule, New Hampshire, Camp Parks, and at Onizuka AFS include a data link terminal antenna which provides communications functions using SGLS.
Other Transmitting Sites. Other than the AFSCN stations, certain satellites are controlled through dedicated sites to support specific programs. The Defense Meteorological Satellite Program has a dedicated network operated by the Suitland Satellite Operations Control Center (SOCC) in Suitland, Maryland. The SOCC performs all primary TT&C functions for the Defense Meteorological Satellite Program (DMSP) through the use of AFSCN assets. The SOCC has a back-up facility at Offutt AFB, Nebraska. The Global Positioning System (GPS) has a Mission Control Center at Schriever Air Force Base operated by the Air Force Space Command, 50th Space Wing, 2nd Satellite Operations Squadron. There are also dedicated GPS monitoring stations at Ascension Island, Diego Garcia, Kwajalein, Cape Canaveral, and Hawaii Tracking Stations.(4)
In addition to the AFSCN, the GMF lists the following facilities that are authorized to transmit on SGLS frequencies:
1. Blossom Point, Maryland
2. Buckley Air National Guard Base, Colorado
3. Cape Canaveral Air Force Station, Florida
4. Fairbanks, Alaska
5. Laurel, Maryland
6. Kelly Air Force Base, Texas
7. Kirtland Air Force Base, New Mexico
8. Quantico, Virginia
Further, the Air Force also has transportable tracking facilities that can be relocated worldwide to satisfy immediate requirements for TT&C, such as anomaly resolution, that cannot be accomplished at the fixed facilities. Under those conditions, the transportable terminals usually operate on Federal land (e.g., military bases and installations). The Navy operates additional sites at Prospect Harbor, Maine; Laguna Peak, California; and Finegayan, Guam. Figure 3 shows the locations of SGLS-compatible uplink stations in the United States.
|Short Name||Number of Satellites*||Orbit**||Short Name||Number of Satellites||Orbit***|
|USGCSS PH 2/3/3B||5 (O)
|MILSTAR||6 (O)||Inclined GEO||STS (Shuttle)||5||Non-GEO|
|Skynet (UK)||1 (O)||GEO||P-Series||7||Non-GEO|
|NATO III/IV||1 (O)
|4||GEO||Various R&D||10||Non-GEO (LEO, HEO)|
|USBUD||4||GEO||Notes: ***Low Earth Orbit (LEO), High Earth Orbit (HEO)|
|Notes: * Operational (O), Standby (S)
** Geosynchronous (GEO)
Conventional Fixed Systems(5)
The military services are extensive users of conventional fixed microwave relay systems in the 1755-1850 MHz band. As mentioned earlier in this report, the U.S. Army Corps of Engineers operates fixed microwave systems throughout the country. All of the Services employ fixed microwave systems on military installations and test and training ranges to support a variety of functions. These functions include general purpose communications to remote areas, relaying radar data from remote range areas back to control centers, relaying video data from remote bombing and gunnery ranges, sending command and control data to tethered aerostat radars and relaying radar data from tethered aerostats to ground control facilities.
The Forest Service of the USDA is one of the Federal Government's largest users of fixed microwave radio sites. These sites provide backbone communications support to land mobile radios in national forests and lands managed by USDA for the public. The backbone links provide primary radio interconnection between mountaintop radio repeaters and the base stations, which further interconnects with either mobile or portable handheld radios. Some USDA microwave links are shared with other agencies such as the DOJ. These systems are essential for law enforcement, firefighting, and emergency preparedness disaster control (e.g., earthquake, volcanic eruption, and hurricane) communications.
The DOI manages its natural resources programs using fixed microwave links to accomplish Congressionally-mandated missions. These microwave operations support a variety of functions including: firefighting, law enforcement, disaster control within national forest and parks, communications services to Native American Tribal lands, and earthquake monitoring. Operations are spread throughout the United States in suburban, urban, and rural areas, some of which are remote and almost inaccessible so that commercial service is not available or reliable.
As a result of the Omnibus Budget Reconciliation Act of 1993 (OBRA-93) reallocation of the 1710-1755 MHz band, the FAA and U.S. Coast Guard (USCG) are in the process of procuring fixed microwave links in the 7/8 GHz band. The FAA uses fixed microwave links as part of a nationwide network to interconnect the nation's air traffic control facilities. The USCG uses are for vessel traffic control and safety operations, communications support of the national distress system, and remote distress and safety communications.
The Department of Justice uses a nation-wide network of fixed point-to-point links to connect its land mobile users. Bureaus within the DOJ have also begun the transition to higher frequency bands (e.g., 7/8 GHz band). These Federal law enforcement systems require secure communications to prevent monitoring, which could disrupt investigations and/or cause life-threatening situations for law enforcement personnel.
DOE has fixed microwave operations in support of the National Defense and Petroleum Reserve Programs with a variety of functions such as remote keying of high frequency transmitters, backbone and security, and remote control of robots, cranes and alarms.
Specific agency applications of the fixed microwave wide-area network systems include the following: the FAA remote data transmission in support of aviation safety systems; the USDA and the DOI backbone links for control of land mobile radio systems necessary in firefighting, law enforcement and disaster control within national forests, and for provision of voice data connections between sites where commercial service is not available; and the Department of Treasury and DOJ microwave links related to law enforcement. This band is also used by the USCG for vessel traffic safety systems, for communications support of the VHF national distress system, and remote distress and safety communications and control networks.
One example of a wide-area network is the DOE and Tennessee Valley Authority (TVA) use of this band for supervision, control, and protection of electrical power transmission. The channels are used for high speed data relaying, supervisory control, load control, telemetering, data acquisition, land mobile radio dispatching, operations and maintenance. The present system connects, via wireline and radio, all Federal Government power marketing control facilities in the western half of the United States and TVA region. Common equipment exists with the non-Federal sector allowing interconnectivity for critical communications dealing with all aspects of generating and distributing power.
The U.S. Customs Service currently operates and maintains an analog microwave system in Hawaii, commonly referred to as the Rainbow Microwave System, that provides a common backbone system servicing Federal, state, and local agencies. Rainbow was included in the list of Federal stations that will remain in the 1710-1755 MHz band due to the high priority, public safety missions it supports, and currently employs frequencies throughout the entire 1710-1850 MHz band. Although Rainbow is protected from interference under the mixed use criteria established by Title VI of the Budget Reconciliation Act of 1993, there is no digital equipment available to replace the aging analog microwave system, due to the reallocation of this band. Therefore, the digital microwave system must operate in higher frequency bands at a higher cost to the users. There is currently a study underway to evaluate this system upgrade and the cost to continue the support of the public safety community in Hawaii.
Tactical Radio Relay Equipment
The DOD uses tactical radio relay for command and control of forces. The majority of tactical radio relay in the band is supported by the MSE. Primary areas of operations for MSE in the United States are shown in Figure 4.
The MSE is a multi-band, tactical line-of-sight radio system, more accurately described as a "system-of-systems," because it is composed of several components, each of which are fully operational systems. The individual components that make up the MSE are dependent upon several portions of the radio frequency spectrum (e.g., 30-88 MHz, 225-400 MHz, 1350-1850 MHz, and 14.5-15.35 GHz). The inability of any of these components to operate successfully would result in the failure of the overall system. One critical component of the MSE, the AN/GRC-226(V)2 radio, is dependent on the 1755-1850 MHz band. It is used to connect radio access units to the node center switch of the network. Operational use plans call for 465 units per Army Corps, giving a total of 2,325 units for five Corps. The AN/GRC-226(V)2 is a digital radio that can tune to any of 4000 available channels, spaced at 125 kHz, between 1350-1850 MHz; however, due to the allocation of most of this band to other services, users rarely have access to spectrum outside of 1350-1390 MHz and 1710-1850 MHz bands. The follow-on radio now in production, the AN/GRC-245, will have extended tuning of 1350-2690 MHz.
The DWTS used by the Navy is a surface-based, frequency modulated, point-to-point and mobile communications system that carries 9, 18, or 36 voice channels or digital data, and can be carried on a high mobility multipurpose wheeled vehicle. The DWTS is used at Camp LeJeune, North Carolina; Twentynine Palms, California; Oahu, Hawaii; and at other military installations and proving grounds where training exercises are conducted. This system is fully deployed with approximately 600 units in the field. The DWTS consists of two systems: the AN/MRC-142 operating in the fixed service at land-based facilities and the AN/SRC-57 operating in the mobile service for ship-to-ship and ship-to-shore communications (land-based AN/MRC-142 units).
Air Combat Training Systems
The ACTS are used extensively in the 1755-1850 MHz band. ACTS are complex by the nature of their operations, because both fixed and aeronautical mobile equipment are used.
ACTS that operate in this band segment include the Air Force's Air Combat Maneuvering Instrumentation (ACMI), and the Navy's Air Combat Maneuvering Range and Tactical Air Combat Training System (TACTS). Two types of these systems are described in the DOD Initial Report: the current ACMI and TACTS (both called ACTS, herein) and the Joint Tactical Combat Training System (JTCTS) which is intended to replace the existing ACTS.(6) These systems provide critical training for and evaluation of aircrews in air combat tactics and performance. These systems are in operation at all test and training ranges as well as other bases including Reserve and Air National Guard locations that may include civilian airports.
Figure 5 represents permanent Air Force and Navy Training sites in the United States. Air Force and Navy ACT S employ factory preset frequencies throughout the 1761-1842 MHz band segment that are used to transmit information to and from aircraft. The DOD has stressed that training support systems such as these are key elements in the military's effort to provide realistic simulation and combat preparedness for pilot training in a peacetime environment.
The U.S. Air Force ACMI/ACTS, the U.S. Navy TACTS, and its several variants provide training associated with aircraft missions ranging from squadron level up to and including joint force missions. The Navy and Air Force use these systems as the final readiness training prior to deployment to combat areas around the world. ACTS provides real-time monitoring of aircraft combat operations and maneuvering, such as gun-scoring, no-drop bombing training, and evasion and intercept tactics and electronic warfare during exercises and training. It also records and plays back aircraft maneuvers for mission analysis and debriefing. The system is composed of the ground-based tactical instrumentation subsystem (ground-to-air) and the aircraft instrumentation subsystem (air-to-ground) mounted internally or via a pod on the aircraft. The two-way data link between these two subsystems is the only means by which they interact and allow the overall system to function.
On the ground, there are remote stations that receive the aircraft downlink signal and transmit commands to the aircraft, and relay the received aircraft data to a master station. Six frequencies are used in the 1755-1850 MHz band for remote stations, and one frequency for the master station to transmit to the remote stations. There are two ground-to-air frequencies, and two air-to-ground frequencies.
During a mission, active Aircraft Instrumentation Subsystem pods are sequentially interrogated on a periodic basis using the same frequency, and each responds when addressed by its unique digital address code. The Aircraft Instrumentation Subsystem transmits both ranging signals and stored digital data over a single channel. Each training range uses 10 frequencies within the 1755-1850 MHz band.
ACTS is employed at ranges in United States, Canada, Taiwan, Thailand, Egypt, Okinawa, Korea, and Italy. Canadian F-18 fighter aircraft are fitted with an internal ACTS box (and dedicated 1710-1850 MHz antenna) for use on the ranges similar to the U.S. Navy F-18's. The Royal Netherlands Air Force uses ACTS with the Arizona Air National Guard at Goldwater Air Field, Arizona. This system is fully deployed and includes approximately 120 tracking instrumentation systems and 1,400 aircraft instrumentation systems.
The JTCTS will operate in the same band, at the same locations, and perform the same function/mission as the ACTS. However, the JTCTS will differ from the current ACTS equipment in several important respects. From the spectrum management aspect, the most significant of these are the dual-bandwidth operation capability, and the spread spectrum nature of the signal. The JTCTS is designed to tune throughout the 1710-1850 MHz band in 5 MHz increments for a total of 27 possible channels. The second major difference is that the JTCTS does not require a dedicated range with numerous ground stations. This mode of operation, called "rangeless", operates in a air-to-air configuration, and therefore, can be used anywhere over the United States or the world in airspace set aside for military operations.
The JTCTS has host nation coordination and permanent frequency assignments for Japan. The United States has also requested host nation coordination for several other countries.
Both the Tactical Instrumentation Subsystem and the Aircraft Instrumentation Subsystem have planned replacements. The Aircraft Instrumentation Subsystem began upgrading to the AN/ASQ-T31 in June of 1996. Plans are to acquire 155 units. This equipment is portable and includes provisions for data encryption. The Tactical Instrumentation Subsystem will be replaced by the JTCTS, which is being developed by the Navy, and is becoming operational. Most of the combat training ranges will be upgraded to JTCTS within a 10-year period.
Other National Defense Systems
Other critical DOD systems, such as precision munitions and high resolution video links, operate in this band and are vital to national defense. Precision munitions include a number of weapons systems that employ communications in this band between a launched weapon and a controlling platform allowing for precision delivery of the weapon's payload. These advanced systems are normally employed against high value and hardened enemy targets. DOD precision guided munitions (e.g., AGM-130 and GBU-15) were designed for employment against fixed, high-value targets. These weapons, in the 2000-pound class, are launched from tactical aircraft from either low or high altitude at ranges from 5 to in excess of 30 nautical miles. Equipped with television or infrared sensors, and aided by GPS, these weapons provide operators the ability to attack targets in all weather conditions, day or night. These weapons can be controlled from either the launch aircraft or a standoff aircraft at a range of more than 100 nautical miles. Operators require access to a video and a command link frequency at any time during the mission, including ground operations, post take-off pre-launch operations, and post-launch weapon flight operations. Access to frequencies is critical during all training operations--these operations require use of the frequencies for two hours at a time.
The weapon control data link systems provide operators with the ability to control the precision guided weapons. Video from the weapon seeker is transmitted to a weapon systems officer who identifies the target and manually controls the bomb to the designated impact point. The AGM-130 provides a longer range, compared to the GBU-15, because its flight is assisted by use of a rocket motor. Both data link systems associated with these munitions, the AXQ-14 and ZSW-1, use multiple frequencies within the 1710-1855 MHz band for both video and command links. The AXQ-14 and ZSW-1 weapon control pods carried on the centerline station on the aircraft, receive the weapon video for display, and transmit weapon guidance signals through the command link.
In addition to precision munitions and high resolution video links, the 1755-1850 MHz band also supports deployable emergency communications systems, combat identification systems, mobile tactical voice and data systems, robotic control functions, and target scoring systems.
1. U.S. Department of the Army, Army Training and Doctrine Command, Army Space Reference Text, Chapter 7, Space Systems, (visited September 13, 2000) <www.tradoc.army.mil/dcscd/spaceweb/chap07a.htm>, at Section 7-1: Control Segments (Telemetry, Tracking and Commanding).
2. See National Telecommunications and Information Administration, U.S. Department of Commerce, NTIA Special Publication 95-32, Spectrum Reallocation Final Report (1995), at 4-13 [hereinafter NTIA Final Reallocation Report].
4. Some of the satellite systems are for the Defense Support Program (missile warning), global positioning system (navigation), Nuclear Detonation Detection System, Defense Meteorological Satellite Program (weather and environmental monitoring), Defense Satellite Communications System (communications), MILSTAR (communications), Fleet SATCOM (communications), and the UHF Follow-on (communications).
5. Conventional fixed systems as used herein refers to point-to-point systems using commercial off-the-shelf, or equivalent equipment.
6. See DOD Initial Report, supra note 3 at E-1.