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 modernizationohowever, 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.
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