Battlefield Navigation: Ancient Problems, Modern Solutions AUTHOR Major Conrad G. Dahl, USMC CSC 1989 SUBJECT AREA - Warfighting EXECUTIVE SUMMARY TITLE: BATTLEFIELD NAVIGATION ANCIENT PROBLEMS MODERN SOLUTIONS I. PURPOSE: To review the identified need, operational considerations, and logistic support requirements for the fielding of the Position Location Reporting System (PLRS) in the Marine Corps and to analyze its future use by combat forces. II. PROBLEM: Over the past decade the Marine Corps has come a long way in terms of modernization and quality of personnel and equipment. In spite of this modernization however, there has remained a void in the area of vehicle land navigation systems as well as man-packed navigation aids. For example terrain orientation in the $2.5 million dollar M-1A1 Tank is still largely dependent on "primitive" tools like the map and compass. The limitations of current land navigation techniques on the modern high-speed battlefield are common knowledge: they are time consuming, cumbersome and frequently inaccurate. III. DATA: An accurate, reliable land navigation system has been determined to be a priority need. The proven technology is on hand and PLRS is currently being fielded to the three MEF's and the fourth Division/Wing Team. The computer based system will provide three-dimensional position, location, and navigation information along with a limited digital, crypto-secure, free text message, burst transmission communication capability IV. CONCLUSION: To date, tests have demonstrated that many of the problems of battlefield navigation, command and control, and communication can be alleviated through the professional planning and use of PLRS. V. RECOMMENDATION: Few people in the Marine Corps or Navy know just what PLRS is or is capable of. It is time for the Marine corps to take active steps to educate all Marines, and in particular those personnel filling planner billets, as to the capabilities of PLRS. This system is undoubtedly the commanders tool of the future, available today, and ready for the true 'thinking " commanders employment BATTLEFIELD NAVIGATION ANCIENT PROBLEMS MODERN SOLUTIONS Over the past decade the Marine Corps has come a long way. We have moved not only in terms of time and space, but also in terms of modernization. In spite of this modernizationœhowever, there has remained a void in the area of vehicle land navigation systems (VLNS). Now, although long delayed by inadequate technology and budget, vehicle land navigation systems are reaching maturity. These systems will constitute true cost effective force multipliers in the area of command and control (C2) for the Marine Corps--and in particular for our mechanized units. Integral to the plans for the modernization of the Marine Corps are recent significant technological achievements gained despite budget limitations, procurement problems and the often given, seldom sought advice that "technology does not win battles." The fact is, that breakthroughs in the application of laser sensors, microprocessors, turbine engines, aerodynamics and other technologies have been a real boon to Marine Corps combat capabilities. All of the advances which we have experienced in firepower, communications, target acquisition and surveillance have not, until recently, been matched by similar progress in land navigation. Terrain orientation in the $2.5 million dollar (plus) M-1A1 Abrams main battle tank (MDT) or in the Light Armor Vehicle (LAV) is still dependent on "primitive" tools like the map, pencil and magnetic compass. Their limitations are common knowledge: they are time-consuming, cumbersome and frequently inaccurate. Consider, for example, the leader of an advancing mechanized column who, unaware that he is disoriented, charges ahead. Following behind, like lemmings, the rest of the unit. Utter confusion, if not disaster, is the result--and this is in broad daylight. A far more typical combat environment could feature cross-country maneuver in terrible weather with units in combat formations and probably receiving fire. Such a circumstance may not bring defeat but the result may be serious in terms of casualties and material losses. The dynamics of the modern high speed battlefield greatly magnify the potential effect of disorientation on its outcome. With land navigation such an obvious need, why has the need remained unfulfilled? While it ia true that their combat dynamics and environments are dramatically different, air and naval forces use sophisticated space, air, and land based instruments in their demanding environments. Why then is there a technical lag for ground vehicles? Perhaps the lag is the result of three related factors: low priority of the requirement, lack of a land navigation system (LNS) practical for land vehicle application, and a tight budget. How important is land navigation to land combat? Would an accurate, viable land navigation capability materially increase combat power relative to the dollar expenditures required? is the high technology needed for a precise, reliable, practical land navigation system for general distribution now available? A combat situation in which a truly viable VLNS could contribute significantly to combat power can be easily visualized. Potential action by a light motorized rapid deployment force in the Persian Gulf area comes quickly to mind. Picture the likely, and unfamiliar environment: widely dispersed forces move day and night across the rugged desert terrain. There is an urgent need to move rapidly, possibly against significant resistance, before the enemy can mass his forces. Rapid changes in direction result in order to meet unexpected situations. Aerial strafing forces vehicles to button up. Radio silence is imposed. Sandstorms occur at critical phases of the operation. Visual landmarks are few or perhaps nonexistent. The situation is ripe for disorientation and chaos. Suppose now that this force is equipped with state-of-the-art VLNS, especially command and control vehicles, artillery batteries, tanks, LAVs, reconnaissance vehicles, as well as fuel and ammunition supply trucks. The system provides accurate and continuous readings in both heading and position (in standard grid coordinates), and provides the option of transmitting "formatted" messages in burst-tone mode. This describes the VLNS. Use of this system means there is no need to stop for visual orientation or map reading. The momentum and direction of attack are maintained despite the formidable obstacles--an enormous tactical advantage. While tropical and arctic environments are entirely different, the merits of the VLNS apply as they do for the desert. Maneuver in these environments may be slowed--but consider such factors as the ambiguity or lack of visual landmarks, the importance and difficulty of night operations, and extremes of weather such as tropical monsoons and arctic snowstorms. Jungle warfare obviously accentuates such problems as coordinating dispersed units, knowing unit locations, delivering fire support, and the difficulty of guiding units in such terrain. Clearly there is a vital need for VLNS in every battle environment. There is no question as to the combat multiplier value of a viable VLNS, but there remain the questions of availability and of cost-effectiveness. The technology is on hand and has been well demonstrated, but is it good enough to buy in light of system costs and budget limitations? A look at today's situation in Europe and in the Middle East may be instructive. Contrary to the conventional view, the Soviets are quick to grasp the relationship between technology and tactics. Soviet combat vehicles, including their BMP infantry fighting vehicles, captured during the 1973 Arab-Israeli war, featured VLNS. Today an estimated 90 percent of Warsaw Pact combat vehicles are VLNS equipped. Throughout NATO there is significant interest in a general use navigation aid which fits the description of VLNS. Some NATO armies employ versions of a VLNS in a limited distribution and primarily to enhance fire control. The microprocessor technology available today makes possible instant conversion of sensor signals into directional heading and position data. Several U.S. and foreign firms have pursued the goal of producing a VLNS over the past two decades. But, for whatever reasons (impractical size, weight, reliability, complexity, cost), the effort did not produced a general use system. Now the Marine Corps has the solution to the vehicle land navigation problem. We are in the process of buying and fielding the Position Location Reporting System (PLRS)--a system which networks user units to tell them where they are, where they are going, and where the other users in the system are as well. A sole-source contract with Hughs Aircraft Corporation will provide the Marine Corps with PLRS at all three Marine Expeditionary Forces and the Fourth Division/Wing Team. Each MEF will receive two PLRS consisting of three master stations and approximately 330 user units which can be widely dispersed on the battlefield. Few people know just what PLRS is, just what the Marine in the field can expect, or just what tradeoffs there are that the commander must address in order to use PLRS effectively. The computer based system provides three-dimensional position, location and navigation information. PLRS also has a limited digital data communication capability which provides operators with the capability of transmitting crypto-secure, free text messages in burst transmissions. Click here to view image The PLRS system consists of two major components, the master station (MS) and the basic user unit (BUU). (See Figure 1.) Just like a Marine Air-Ground Task 1PLRS--Position Location Reporting System AN/TSQ-129 Handbook. a publication of HUGHES AIRCRAFT COMPANY, Hughes Ground Systems Group, Fullerton, California (May 1984), p. 13. Force (MAGTF), PLRS will be organized for the task at hand as determined by the commander. The MS serves as the brains and heart of the PLRS. (See Fiaure 2.) Click here to view image The MS consists of three standard computers which provide all ranging computations, coordinate conversion (to map coordinates), graphic displays, and network management for the system. It is housed in a standard S-280 shelter and powered by a 30-kilowatt generator. The shelter comes equipped with its own air conditioning units, 5-ton truck, and a section of operators and maintenance personnel who have their own maintenance van. 2PLRS--Position Location Reporting System AN/TSQ-129 Handbook, p.17. The BUU is the second major component of PLRS. (See Figure 3.) As the name implies. it is the component most obvious to the user. Each system can accomodate up to 370 BUU's, which come in either a manpack, surface vehicle, or aviation configuration. The user unit designed for use in a surface vehicle adds a power unit adapter, cables, and a larger antenna to the BUU. The one configured for use in an aircraft adds a unique antenna and a different man-machine interface called a pilot control display panel (PCDP). Click here to view image 3PLRS--Position Location Reporting System AN/TSQ-129 Handbook. p.21. The BUU. without ancillaries, weighs approximately 14 pounds. The man-machine interface, or user-read-out (URO), antenna, batteries and box, and ALICE pack frame increase the weight to about 22 1/2 pounds. The attempt to keep this weight as light as possible. while not eliminating any of the system's capabilities resulted in the major portion of the hardware being housed in the MS, with the trade off being the man-portable BUU. When a PLRS user unit is activated, the Master Station assigns it a transmission time slot and calculates the units location to within 15 meters circular error probability (CEP) for ground based systems. and 25 meters CEP for airborne platforms. Covertness and anti-jamming capabilities are achieved through the use of burst transmissions--800 millisecond bursts in a spread spectrum frequency hop of 8 hops per transmission. Locations are updated every two seconds for airborne units and every two minutes for ground units. It will not be necessary for a commander to become a PLRS technician. but like any system on the battlefield, an understanding of how it works will provide helpful clues for its most effective and efficient employment. There are three basic concepts which must be understood in order to realize how the system works. The first two are easily understood while the third will require some detailed explanation. First, PLRS uses radio signals as a basis for its computations. Like a radio, both the MS and the BUU are transmitters and receivers. Second. PLRS radio-like transmissions are time ordered. That is, each BUU transmits only during a time slot specified by the MS. Third, PLRS is a relative positioning system. The user community's location is calculated relative to at least three units in the system. Accurate knowledge of at least three other reference units allows the MS to calculate the positions of all other units in the network. The solution to the land navigation problem which PLRS provides is obvious. Additionally, it provides the commander with a new flexibility--enhanced positioning, command and control, and navigation are but a few of the areas which will benefit. When fully employed, every function of the modern battlefield will feel the effect of this system. When operating in an offensive action, the commander will validate locations of adjoining units by asking PLRS for their grid and range or bearing. By the same technique he can ensure his subordinate units are in proper positions for a defensive action. On the ground, navigation between objectives will be precise, as terminal guidance is received in the form of continual range and bearing instructions. In the air, three-dimensional helicopter corridors can be constructed and pilots provided with the same type of guidance. Restricted zones, such as no-fire areas and minefields, can be programmed and labeled. Warnings, restrictive information, and exit/evasion guidance will then be provided before a zone is penetrated. As with any addition to the Marine Corps' inventory, PLRS "pros" come with some "cons." PLRS features are largely designed to provide maximum capability to the user while minimizing operational complexities. The trade-offs are generally to the advantage of the commander while the burden of support requirements are centralized to the rear. The user, however, is not exempt from having to consider trade-offs. Two are immediately apparent. First, the manpack weighs 22 1/2 pounds. The infantry commander is therefore forced to use one of his Marines to carry the unit. The gains probably far outweigh the loss, but there is a loss. Second, in order to possess PLRS capabilities, the user must make his position known automatically to higher headquarters. This may be an motional issue in some quarters as it raises the question of PLRS being used as a tool for "micro-management." Will a MEB commander be tempted to manipulate platoons now that he has an accurate, real-time display of all his forces? This is a possibility, but not one worth much concern. Sound commanders will undoubtedly make prudent use of their new technological capability. Real trade-offs will begin as you move further to the rear. Effective use of PLRS is going to require detailed planning and coordination. The PLRS appendix to the communication annex to the operation order will become a standard consideration. Matters such as message set assignments (who has access to what unit locations); allocation of predesignated locations (objectives, checkpoints, link-up points for which range and bearing are provided); contents of notices (weather reports, rearm/refuel points, passwords) must all be thought out, coordinated and circulated as a part of the operation planning. Such coordination and planning will become a part of preoperatlon administration and will probably accommodate PLRS when more Marines become familiar with the system. Who will be responsible for PLRS is the real question. The communications officer may be a likely candidate since the PLRS appendix will be attached to his communication annex. PLRS also uses radio signals and, therefore, might qualify to be treated as a radio. Even the MS operators are communicators. As convenient as this seems, however, PLRS information will be of primary concern to the S-3 officer. He will coordinate the operations order and make tactical recommendations to the commander based on the battlefield situation. The S-4 officer will also be deeply involved. Resupply points, medevacs, generators, POL, and maintenance are all concerns that impact on the S-4's area. Ultimately, of course, the commander is responsible. But PLRS is new equipment that introduces new capabilities and concepts, and complete procedures for its use don't exist yet. The Fleet Marine Force (FMF) will simply have to wrestle with the system for a while to arrive at an acceptable standard operating procedure. A somewhat more perplexing problem faces the Marine Corps if the commander decides he wants to use PLRS operationally during the ship-to-shore movement of an amphibious assault. The first question is will the Navy allow PLRS to be turned on? The amphibious task force commander may want to maintain emission control (EMCON) and not allow PLRS signal to be transmitted. If the Navy does allow PLRS to be turned on, then the commander faces another consideration. The MS requires 25 watt, 3 phase, 60 hertz. grounded (5 wire) electrical power. Navy ships have only ungrounded (3 wire) for safety considerations. A match can be made if military specification transformers are embarked that provide the needed grounded power. The trade-off is in the effort needed in advanced planning for the transformers and appropriate power cables and connections. Another consideration is that the MS antenna must have a line-of-sight to the shore or to a relay station. This means either deck mounting the MS or remoting the antenna. If deck mounted with the generator close at hand, the problem of the transformers can be overcome by using generator power. Again, close coordination with the ship is necessary. If deck mounting is impossible, the MS antenna can be remoted up to 200 feet to allow operation from below decks. Routing and placement of antenna and cables will have to be an item for preembarkation discussion If the Navy does allow the employment of PLRS shipboard, there is still one more technical coordination question: how to establish the three reference units? Options abound for this operational problem. The least complicated solution would involve placing reference units ashore with recon elements. BUU's on there separate ships could provide a solution, however, it is doubtful a ship would remain at anchor during an amphibious assault. The reference units cannot move with the current configuration of PLRS unless new positions are determined and fed to the computer ever 16 seconds. Anchored bouys are another option. If this plan is pursued, embarkation and emplacement prior to H-hour is one more consideration which must be coordinated with the Navy. The solution to the problem may lie in the interface between PLRS and the Global Positioning System (GPS). GPS provides extremely precise position fixes using satellite signals. The Marine Corps is looking at purchasing a limited number of these GPS units for the purpose of "anchoring" the PLRS reference units. An accurate, reliable land navigation capability has been determined to be a priority need. The proven technology is on hand and PLRS is on the way. Delivery of the first production units was made to the First MEF in September of 1987. It has since been certified as safe and ready for follow-on tent and evaluation. To date, tests and evaluations have demonstrated that many of the problems of battlefield navigation. command and control, and communication can be alleviated. PLRS is one more tool to benefit the commander. Broad distribution of the system is about to commence. Soon those tankers in the Persian Gulf scenario--blind in their closed turrets, beset by sand clouds and countermeasures, their radio useless--will, nevertheless, know where they are and where they are heading. BIBLIOGRAPHY 1. Barlow, David A., Capt., USA. "NAVSTAR On The U.S. Army Battlefield." SIGNAL (January 1989), 51. 2. Barton, B.M., Capt., USMC; Brogan, M.M., Capt., USMC; Wilkes, K.R., Capt., USMC; Deward, W., Lt., Thailand Marine Corps. "Position Location Reporting System (PLRS) Concept Of Employment In The Marine Air Ground Task Force." 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