Globalstar for the Military

I

I Globalstar for the Military

I Rich Hendrickson Kent Penwarden Loral Qualcomm Satellite Services, Inc. I Palo Alto, California

cables have extended these networks world­ I ABSTRACf wide between regions served by wireline Globalstar, a new satellite-based mobile telephone companies. Terrestrial cellular I voice/data telephone service, is being radio has expanded the scope of these planned by LQSS for operation in 1998. It networks to mobile users, typically in will let military personnel, using handheld, populated urban centers. I ship-board, or vehicular mobile terminals in With Globalstar, DoD will have the even the most remote areas of the world, to opportunity to extend the reach of its stay in contact with each other and with telecommunications networks to the most personnel who are on established remote regions of the world, without being I communication networks. A constellation of constrained to telephones connected directly 4810w-earth orbiting (LEO) satellites and an to the wire-line networks. Communications advanced method of digital signal formatting equivalent to terrestrial cellular radio will be I will provide low-cost and reliable voice, data, available over areas vastly greater than those fax and position-locating services to military served by terrestrial cell sites. While not personnel in most areas of the world. intended for war fighting applications, the I Globalstar will interoperate with existing Globalstar satellite system will serve as a local (domestic or foreign), long-distance, backup and supplement to military public, private, terrestrial-cellular, DoD, and communications systems. I specialized telecommunications networks. The system will permit the military, for its 2. SYSTEM DESCRIPTION general purpose communications, to share I with commercial MSS (Mobile Satellite In the Globalstar world, from handheld, ship­ Services) at low cost. board, and vehicular terminals, military and other DoD personnel will be able to place This paper includes an overview of the telephone calls from distant lands and seas to I Globalstar system and describes possible any telephone on existing DoD applications. telecommunications networks. (See Figure 1.) Personnel can be located and called, or I 1. INTRODUCflON can call any other handset or telephone in the DoD has established highly survivable world. One telephone number can be communications systems for serving the assigned to an individual, not a place. Digital I needs of the U.S. Armed Forces in war signal formatting with spread-spectrum fighting conditions. However, most DoD modulation will allow the ready application communication takes place during times of of DoD security measures such as STU-III I peace and outside of regions of conflict. For telephones to an already private system. that reason, the DoD places a significant The low altitude of the Globalstar LEO volume of traffic over commercial satellites permits the use of low-power I telecomm u nication s networks. handsets. Globalstar provides multiple­ Geosynchronous satellites and under-sea satellite coverage to allow true "space" I 1 I Globalstar for the Military I

diversity to mitigate against· blocking and capable of being extended to avoid I shadowing, to enhance traffic call capacity, propagation blockage by the user's head and and to provide fail-safe operation. Globalstar to minimize radiation effects, and it will be takes advantage of CDMA (Code-Division collapsible for stowing. Multiple Access) call transmission format to I increase spectrum usage. Globalstar includes Platform-Mounted Terminals a simple satellite design, which does not rely Globalstar mobile terminals will be equally I upon expensive, less flexible, and potentially applicable for vehicle operation, for less reliable satellite-ta-satellite call transfers. shipboanJ operation, or for aircraft operation. The Globalstar ground segment can be either The primary differences between handsets shared commercial, or dedicated military, and platform-mounted mobile tenninals will I fixed-site gateways, or be transportable be in the packaging and the power supply. gateways to serve special contingency Packaging will separate the antenna from the operations anywhere on earth. Gateways will transceiver to mount the antenna external to I serve mobile stations within a range of many the platform envelope. Antennas could be hundreds of kilometers and will provide mounted to the top of masts to clear local access to terrestrial networks either directly or trees or superstructure obstacles. Aircraft I by way of a fixed satellite service link. antennas would have to be integrated with the 2.1 Mobile Teoninals airframe, but the small-sized, patch antennas will allow for flush, surface mounting. I Three basic categories of Globalstar mobile Terminal power will be obtained from the terminals will be handheld, vehicular, and vehicle battery and/or power system. fixed. All Globalstar mobile terminals will share essentially the same signal processing Fixed Terminals I and RF characteristics, so that they will Globalstar fixed terminals will be those appear to the Globalstar LEO satellites and intended for permanent installations in gateways as equivalent terminals, although I remote regions having no access to terrestrial type identification can be associated with the telecommunications networks. Power could tenninal identification in network control. be derived from solar panels or other local I Mobile tenninals can be built with dual-mode power source. The antenna, the solar panel, - and even multi-mode - operation for and terminal would be packaged for pole compatibility with any terrestrial radio mounting, with the antenna high enough to I network, including existing analog cellular clear the adjacent trees. radio in the USA and other parts of the world. 2.2 Satellites I Handheld Terminals Constellation The Globalstar LEO satellite constellation Handheld tenninals will be in appearance and will be comprised of 48 satellites arranged in operation much like terrestrial cellular radio I 8 orbital planes. (See Figure 2.) The circular handsets, with a few notable differences. A 0 low-power transmitter of approximately 0.2 orbital planes will be inclined 52 from watt average power will maximize both equatorial. The constellations are designed to I battery life and safety. A patch antenna will provide at least one satellite in view above provide dual-frequency-band operation: L­ 100 elevation angle for all latitudes up to 700. band for the up-link and S-band for the Multiple satellite coverage will be nearly I down-link. It will have a horizontal omni­ always available. The circular orbit altitude directional and vertical hemispherical pattern will be approximately 1400 kilometers (756 for communicating with the LEO satellites as nautical miles) with a period of 114 minutes. I they pass overhead. The antenna will be I 2 I I Globalstar for the Military

I PCN (Personal Communications Networks), Satellite Communications Payload FTS-2000, DISN (Defense Information The Globalstar LEO satellites will be small in System Network), and FSS (Fixed Satellite I size and uncomplicated. The Services). Globalstar gateways will serve as communications payload is designed to relay Globalstar network nodes for routing signals signals between the user terminals and the through satellites and beams to the designated I gateway earth stations through linear "bent­ user terminals. pipe" transponders. Communications with Commercial gateways will be owned and the Globalstar gateway earth stations will be operated by the providers of MSS (Mobile by way of separate C-band frequencies for I Satellite Services) for geographically-defmed both the up and down-links. service areas. With the diversity inherent in For communication with mobile user the' Globalstar system, more than one service I terminals. a satellite will have multiple provider can operate in the same or antenna beams, formed by flat arrays of overlapping service areas. DoD and other active and passive antenna elements. which agencies could own and operate their own I will produce multiple footprints on the gateways, typically at bases in remote regions surface of the earth. Each footprint will of the world, or they could share gateway provide L-band up-link and S-band down­ functions with friendly foreign and domestic I link communication. The ensemble of a commercial operators. Transportable single satellite's footprints will cover an area gateways could provide autonomous in­ on the surface of the earth of approximately theater service to rapidly-deployed forces 26 x 106 km2 (10 x 106 mi2). where a user at anywhere on earth (useful up to 700 latitude). I a range of 2900 km (1800 mi) will still view the satellite at minimum of 100 elevation RF Subsystem angle. Three 2.4-meter antennas at each gateway site I will track three satellites in view at anyone Satellite Operational Control time. An RF subsystem will consist of Two Globalstar Satellite Operations Control LNA's and HPA's mounted on an antenna I Centers. to be located on the east and west assembly and, within the gateway equipment coasts of CONUS. will provide for shelter. frequency synthesizers will provide constellation management, with 1) ephemeris the frequency division mUltiplexing for the I determination, 2) planning and scheduling feeder-link signals while modems will be operations for active, retired, and spare provided for every active satellite beam. satellites in orbit, and 3) in-orbit testing. I T&C (Telemetry & Command) stations. Routing Matrix for Handoff collocated with selected gateways to provide Routing traffic to and from mobile terminals worldwide coverage, will accomplish the through the several satellites in view and I control of the satellites during launch and through selected active beams on each movement to their assigned orbits, and satellite will be accomplished by a baseband continue to provide C&S (Control & Status) routing matrix, connecting modems to traffic I communication during operation. circuit units. 2.3 Gateway Earth Stations Gateway traffic circuit units. one for each I Globalstar gateway earth stations will provide data or voice conversation. will provide for access between the Globalstar system and handoffs from satellite to satellite and from other telecommunication systems, such as beam to beam, will encode/decode the PSTN (Public Switched Telephone CDMA waveform at baseband to/from I Networks), PIT (Postal Telephone and analog voice or to/from data, and will provide the I/O to the external world. Incorporating I Telegraph networks in foreign countries). 3 I I Globalstar for the Military

"make-before-break" combining (rather established technology for military I "break-before-make" switching), Globalstar­ communications that has been applied only handoffs will be seamless to data recently to digital cellular radio communications, without the switching communications and other advanced wireless I disruptions currently experienced with data technologies. communication in analog terrestrial cellular Each digital signal to be placed into a radio operation. frequency channel will be coded with a I RDSS different higher-data-rate pseudorandom binary sequence during the modulation Globalstar Gateways will provide for Radio process, which will spread the signal I Determination Satellite Service (ROSS) to spectrum over a wider bandwidth. In a locate user terminals on the surface of the frequency channel carrying multiple COMA earth. From two successive round-trip time signals, interference will be accepted but I delay measurements of a gateway-user­ controlled with the goal of increasing system gateway signal, the user location may be capacity. CDMA does this effectively calculated by triangulation. Location because it is inherently an excellent anti­ I accuracy of less than 1 km will be possible. interference waveform. 2.4 CDMA. Frequency Division. and . The CDMA signal format and network System Capacity interfacing for Globalstar is derived from the I The multiple access scheme to be employed latest, tested and demonstrated Qualcomm. by Globalstar is CDMA (Code Division Inc., terrestrial-cellular-radio technology, Multiple Access) which will be used in which places Globalstar in a significantly I combination with frequency division. The advanced state of development. fIltering and signal processing technique will allow the different signals from many Frequency Division I simultaneous users that want to use the same In the Globalstar system, the frequency band electromagnetic spectrum to have their available to MSS for user-satellite signals separately received and demodulated communication will be divided into smaller I without crosstalk. The scheme includes frequency channels, where each channel directive antennas on the satellites and at the carries the combination of multiple distinctly gateways so that signals propagate to the different conversations, each of which can be I intended user terminals but not to (very distinguished by means of CDMA. (See many) unintended user terminals. Figure 3.) The CDMA codes can be reused Voice conversations to be transmitted are in adjacent frequency channels, which I first analog-to-digital converted by a provides for interference coordination and variable-rate vocoders to reduce the required avoidance. transmission band width for purposes of The gateway-to-satellite feeder links use I traffic capacity expansion and to enhance the another level of frequency diversity to carry signal-ta-noise ratio quality and reduce the the many frequency channels. each with transmitter power required for each multiple summed CDMA signals, to and I conversation. from the plurality of satellite beams of the several satellites. Polarization diversity is CDMA employed on the feeder links to reduce the I CDMA is the best technique for providing required bandwidth by half. spectrum-efficient, economical, and quality digital Mobile Satellite Service. CDMA is a System Capacity modulation and multiple-access spread­ The capacity of the Globalstar system will be I spectrum communication scheme, a well- the capacity that can be carried by the sum I 4 I I Globalstar for the Military

I total of all the Globalstar satellites at one 2.7 Network Management time. Predicting traffic loading is a statistical exercise, because some of these satellites will It is in the realm of network management that I be over minimal traffic regions and some DoD requirements may be most over heavy traffic areas, where heavy traffic dis tinguished from commercial areas will only present a maximum load on a requirements. DoD will operate in a manner I satellite at specific times of day (e.g., rush similar to a private sub-network within the hours) or possibly during specific events overall Globalstar system. Capabilities will (e.g., military contingencies). The capacity of be added for special DoD handling of user Globalstar in CONUS will be 6500 duplex access, call processing, and call management, I circuits available 100 percent of the time and as required for control of the more than 100,000 circuits world-wide. telecommunications resources and for security considerations. Secure DoD I 2.6 Pro,paeation Issues and Diversity controlled user access to the DoD sub­ The Globalstar system is designed to have network will be achieved by dedicated DoD several satellites in view of one mobile data bases, centrally maintained by a DoD I tenninal at one time, to provide the user the Network Access Control Center. Domestic opportunity to transmit and receive by way of and foreign commercial Globalstar operators the satellite with the best available signal, or throughout the world will maintain a network I to combine all available signals to produce an control system that will ensure that service even better signal. In situations where a will be available to the DoD sub-network. particular user-satellite path may be blocked This management function also includes I by a structure or shadowed by trees (See C&S (Control & Status), performance Figure 4.), Globalstar satellite diversity will monitoring (of traffic call completion and provide the user access to a second or third quality), and accounting (billing) functions. I satellite in view. This diversity scheme will Much of this management will be achieve a high degree of circuit availability accomplished in software by means of and will allow each mobile user terminal to hardware storage media for automatic I operate at a lower power level and with processing but with display to operators of longer battery life than would be possible in the Globalstar system. order to achieve the same high availability I with more powerful transmitted signal levels. Network Control Center In fact, building blockage could preclude Globalstar Network Control Centers will be communications without Globalstar's satellite owned and operated by Globalstar. to provide diversity at almost any reasonable and safe for a centrallized management of the I power level. telecommunications assets of the Globalstar Both the Globalstar Gateway and the user system. These centers will balance the terminal will be designed to accommodate overall traffic requirements or a large I doppler shifts due to satellite motion, both in geographical and/or political region by the frequency and in the data rate. Doppler assigning frequencies and codes to Network effects associated with the feeder links can be Coordination Gateways. I pre-corrected. The LEO satellite two-hop latency delay of less than 25 milliseconds, Network Coordinatine Gateway considerably less than the 250 milliseconds Distributed network control functions, in I of a geosynchronous satellite link, will be addition to those performed by centralized imperceptible during voice conversations. Globalstar Network Control Centers, will also be performed at certain operator-owned I Globalstar Gateways, in which case they will be identified as Globalstar Network I 5 I Globalstar for the Military I

Coordination Gateways. For the operator's terrestrial cellular radio systems where it I service area, this will include the control of provides for the user "roaming" function. internal network access by Globalstar mobile Upon entering a service area which is not the terminals, and control of external access at user's home service area, an extended call I the interfaces with other telecommunications setup procedure must be completed for the networks. initial call in the new service area, whereby Internal access by Globalstar mobile the local Globalstar gateway must query the I terminals assigned to DoD operations and user's Home Location Register to authenticate control of external access of DoD networks the user. Thereafter, for the approved may be placed under the direct control of duration, visitor access will be authorized by I DoD personnel. The DoD network control means of the local Visitor Location Register. hardware and software need not be collocated Security with a commercial Globalstar Network I Coordination Gateways but may be located Globalstar will be inherently more secure within the physical confines of a secure DoD than a typical communications system. The facility, with interconnection with a CDMA signal is spread by means of a commercial Globalstar Network pseudorandom code of noise-like nature over I Coordination Gateways or the Network a bandwidth much wider than the bandwidth Control Center by way of secure terrestrial or of a typical VHF or UHF radio. Each FSS (Fixed Satellite Service) data conversation will be encoded and must be I communications media. decoded by a unique code phase of the long pseudorandom sequence. The relatively high TeoninaI Control LEO satellite doppler frequency and timing I Terminal control includes the assignment of offsets will make it difficult to casually mobile terminals to DoD users and the' intercept a Globalstar conversation. Call operational procedures that apply to classes authentication procedures will make it more I users. One terminal may be assigned to one difficult to place an unauthorized call. user or to a group of users. Globalstar data communications rate of 2.4 The internal access by Globalstar mobile kbps or more will support a digital STU-III I terminals may be managed at a Network telephone conversation. Coordinating Gateway by means of two data bases much in the same manner as is 3. MILITARY APPLICATIONS I accomplished in a terrestrial cellular radio Plain Old Telwhone Service Extension system. Two identifications, one communicated by the DoD mobile terminal DoD is a major customer of POTS (Plain I itself and a second being the DoD user Old Telephone Service) for its day-to-day password, would be verified in the Home operations, using these ready means of Location Register (directory data base) in a communications to provide administrative, I DoD Network Access Control Center. The logistics, financial, and morale-boosting Home Location Register maintains records of personal communications. These calls are all legitimate users within the operator's local predominately dial-up person-to-person I service area. Authorization to use the rather than conference or party-line calls. Globalstar network will be returned to the Data communications traffic is increasing as user terminal during call setup. Call priority the result of inexpensive FAX messaging I and precedence as well as call restrictions and personal computer networking. The could be associated with the user's password. primary use of Globalstar will be to extend voice and data POTS to remote areas not A second register will be identified as the I served by terrestrial wire-line telephones or Visitor Location Register. also typical of I 6 I I Globalstar for the Military

I by terrestrial cellular radio systems. As such be contained in a vehicular transportable Globalstar can extend the coverage of shelter which, with the gateway antennas, networks such as DISN to users overseas could be brought to site aboard a military I and to areas not adequately served by other transport aircraft and be set up within hours. terrestrial telecommunications systems. U.S. Armed Forces could be issued Globalstar handheld units prior to transfer I U.S. Navy Awlication and deployment in theater for use during It can be anticipated that a great demand for amphibious landings or during the Globalstar services will be for U.S. Navy establishment of an airstrip. While the I ship-to-shore and ship-to-ship majority of the communications might be communication. Globalstar will permit local to the operation, handheld terminals personnel aboard a ship (within range of a could be allowed access to any other commercial or dedicated Globalstar telephone network in the world through a I Gateway) to place authorized calls to any Globalstar transportable gateway by way of a telephone in the world simply by dialing a collocated transportable VSAT FSS link. phone number on a Globalstar mobile I terminal, which itself could be accessed Special Operations through the ship's PBX. Likewise, a In countries where the local PTT has telephone call placed anywhere in the world established a Globalstar service area, or at I can be placed to a mobile terminal aboard least may be served by an adjacent country's ship. Sailors on deck could use handheld Globalstar gateway, service to special terminals for ship-to-ship communications operations and intelligence missions can be I during maneuvers. Navy terminals could be supported. These missions would utilize the used for communication with foreign ships ability of Globalstar to support clandestine. which do not share a common military rapidly-moving, widely-separated units. I communications system with the U.S. Navy Undoubtedly the secure digital but which are equipped with commercial communications capabilities of Globalstar Globalstar handheld or ship-board terminals. would be utilized in these operations. I Gateways serving ocean regions could be ;Qisaster Relief Coordination those owned and operated by foreign PITs in neighboring maritime countries, or those Of course, with portable communications I owned and operated by DoD which may be capability, disaster relief coordination will be located at selected Navy bases, or ones that an obvious application. Operating by way of are installed aboard a (communications) ship fixed Globalstar gateways remote from the serving a fleet at sea. disaster area, or by means of transportable I Globalstar gateways flown in for the Transportable Gateway purpose, means can be provided for rapidly A possibly more imaginative application establishing emergency communication. I Disaster relief teams within the disaster­ would be in a contingency operation, where U.S. Armed Forces might be deployed to a affected area can report back to an unharmed I remote region of the world where the local area to convey accurate damage assessment telecommunications network could not be followed by requests for food, shelter, and medical personnel and supplies. With ready relied upon. Globalstar mobile terminals access through Globalstar to the PSTN, could provide for logistics communications victims of the disaster can make contact with I to back up rapidly moving Forces, where systems such as MSE have yet to be worried relatives. deployed. A single transportable Globalstar I gateway could be deployed to serve the entire I theater of operation. Such a gateway could 7 I Globalstar for the Military I

Orbiting (LEO) satellites. Gateway earth 4. SUMMARY stations will provide interconnection between I Globalstar will extend voice and data the LEO satellites and other networks, such telecommunications services to and from as terrestrial telephone, radio, or satellite I handheld, vehicular, and fixed user terminals.. systems. Communication network control & Globalstar will be an extension of the status will be accomplished by means of a telephone network, a complementary service hierarchy of Network Control Centers and to terrestrial cellular radio, and will provide Network Coordinating Gateways, while I affordable and reliable voice, data, FAX and satellite control & status will be provided by position location to U.S. Armed Fo;ces, Globalstar for all system operat9rs. other DoD, and Government personnel Globalstar will provide an inexpensive way I worldwide. This communication service will to break through geographical barriers of be extended over vast areas of the earth by personal communications. way of a constellation of 48 Low Earth I I I I I I I I I I I I I 8 I I Globalstar for the Military I Constella6on SateUile Operations 1-__SIatus__ --I Network Control I Satellites Control Center Center Terminals I Globslstar Gateway Ephemeris caller UpcIaIes Authenlica60n I Giobaistar Gateway I Equipment I

COMA Protocol Traffic Convertor I Vehicular Circuits I

Mobile Telephone Switching Office I orTTC-39 Ship-board

I 1...-___ Telephone Network I I Figure 1 Globalstar Network Elements I I I I I 9 I I Globalstar for the Military I I I • 48 satellites in 8 orbital I planes at 1,390 km altitude and 520 mcunawon- 'I- 4-:. I • High capacity, multiple satellite worldwide I coverage between±7oo latitude I • Single-Sate11ite coverage area diameter 5,700 km (1oo elevation angle) I I

computer generated I view from 450 West longitude 200 North latitude I I Figure 2 Globalstar 48 Satellite Constellation I I I I I 10 I I Globalstar for the Military

I Single User Circuit Frequency Channels I 5 6 7 8 9 10 11 12 13 I ~ ~ IIIII ~NXCDM!CirCUits I ...... 1----13 x 1.25 MHz"" 16.5 MHz ... User-Satellite Links I \ I 3 Satellites x (Example) 6 beams pe\ellite - 18 Possible Appearances I

I Antenna #1 --.J I1111 :~~~~1: LJ Illtl ~~~~3: LJ II ttl ~m:~s: I RHCP Satellite #1 illill :~+i~2: n IIITI :+*H n Illtl H~~+: ILHCP I Antenna #2 --.J 11II1111111 LJ 111I1111111 LJ Illtlllllll L Satellite #2 illllllllill n 11111111111 n II H-t 1111111 I Antenna #3 --.J 11111111111 LJ 11111111111 LJ 11111111111 L Satellite #3 illltlllllil n 11111111111 n 111111111111 I Gateway-Satellite I Feeder Links I

I Figure 3 Globalstar Frequency Plan I I I 11 I Globalstar for the Military I I I Clear I I , Shadowed , Blocked I I ~~~~, , I i I I Figure 4 Globalstar Propagation Satellite Diversity I I I I I I I I 12 I