Table of
Contents

APPENDIX G

COMMUNICATIONS

This appendix gives an overview of Patriot communications and equipment to aid in communications planning. The Patriot system relies heavily on data and voice communications. For more complete information, see FM 44-85-1 (TBP).

BATTALION COMMUNICATIONS EQUIPMENT

Patriot uses many types of communications equipment, each with its specific use. The following paragraphs describe communications equipment found at battalion level.

VHF-FM

At the battalion and battery levels, FM radios are in command, logistics, administrative, intelligence, and operations vehicles. Primary FM radios are the SINCGARS with secure COMSEC devices.

IHFR-AM

This is used primarily as backup communications for C2 when at a static position. The AN/GRC-106 radio with the dipole antenna is used at battery, battalion, and brigade CPs.

MOBILE SUBSCRIBER EQUIPMENT

The mobile subscriber equipment (MSE) consists of an interface box at the ICC and is hardwired to a small extension node (SEN) van which will transmit the signal to other SENs. The purpose is to allow the battalion to communicate with higher echelons, other ADA units, and anyone in the net.

UHF

This is the main method that Patriot FUs use to communicate using voice and data channels. The AN/GRC-103, 12-channel, Band III radio sets are in every ICC, ECS, and CRG. Two corner reflector antennas are used for short-range communications, and the AMG is used for long-range communications. Encryption is provided by the KG-194A. The UHF system transmits data through the following methods:

Wire

WD-1 and 26-pair cables are used to connect elements within the battalion and battery for C2, administrative, logistics, and CSS. To enhance the capabilities, the wire lines are connected with the UHF to communicate with higher and supporting units.

BATTALION COMMUNICATIONS REQUIREMENTS

The communications system for Patriot battalions must provide reliable, real-time or near real-time information to dispersed Patriot batteries, higher headquarters, adjacent battalions, and supported units. The communications system must be redundant to provide continuous communications even when the primary system fails. To effectively defeat the air threat, the Patriot battalion must maintain communications to support--

Each Patriot battalion commander is responsible for establishing an effective communications system. He exercises C2 of organic signal assets through his signal officer. The doctrinal responsibilities for establishing communications are found in FMs 24-1 and 101-5. Communications are established from higher to lower, left to right, and supporting to supported, (see FM 24-1). The battalion uses multichannel radio and wire nets to maintain external and internal communications. A communications platoon organic to the Patriot battalion provides external and internal communications for the battalion TOC (extended multichannel radio systems) and limited support to the FUs.

EXTERNAL COMMUNICATIONS

External communications are established with the ADA brigade and adjacent Patriot battalions. The battalion is also capable of communicating with a CRC, brigade, SHORAD, or a Hawk battalion.

ADA Brigade

Communications with the ADA brigade supports air battle C2. It also facilitates administrative, logistical, operational, and intelligence functions. The brigade signal operations company establishes the voice and data links via multichannel radio and MSE between brigade and battalion.

The EAC ADA brigade uses organic MSE resources to install, operate, and maintain a multichannel system between the brigade and subordinate HIMAD, Patriot, and SHORAD battalions. The corps ADA brigade is supported by the corps signal brigade, normally with an MSE SEN at brigade headquarters and required resources at the Patriot battalion location. The Army tactical data link (ATDL), intelligence and radar reporting (IRR), and air defense control (ADC) are circuits routed over the multichannel system.

Generally, three channels are used for control of the air battle. One channel is used for the automatic data link which uses ATDL-1. Another channel is used by the brigade and battalion tactical directors for the identification function. This is called the IRR line and is usually established on party line two. The third channel is used by the brigade and battalion tactical director assistants (TDAs) for the engagement function. This is called the ADC line and is usually established on party line one. All voice circuits are terminated at the ICC patch panel. The automatic data link is also terminated there, either at the RLRIU or at a modem.

IHFR-AM is used as a voice system for ADC and IRR (see Figure G-1). Battalions establish the AM net with brigade to pass messages and facilitate command, control, and coordination with higher echelons. Because of effective internal communications using UHF links, only a backup AM between battalion and brigade is required.

Adjacent Patriot Battalions

A Patriot battalion establishes a UHF multichannel communications system with an adjacent Patriot battalion. Generally, one terminal of a CRG is used by each battalion for this external communications link. The link can also be established by the EAC ADA brigade. Because the Patriot UHF equipment provides a more effective link, use of CRGs is recommended for interbattalion communications. The battalions exchange selected information using the Patriot air defense information language (PADIL) at a data exchange rate of 1,200 bits per second. The information is exchanged to improve fire and track coordination.

Supported Unit

Patriot battalions should establish communications with the supported unit or the unit in whose area the battalion is operating. The battalion normally coordinates with the ADCOORD officer on ADA functions. The Patriot battalion will provide early warning to the supported unit using the Patriot command net.

Supporting Unit

Supporting units establish communications with the supported unit. Normally, the direct support (DS) Patriot maintenance company collocates with or sends a liaison element to the Patriot battalion headquarters. If this is not feasible, the DS Patriot maintenance company enters the Patriot battalion VHF-FM administrative and logistics net. All other units which provide support to the Patriot battalion on an area basis normally do not establish communications with the Patriot battalion. The ADA brigade establishes communications with the COSCOM and TAACOM to provide support for Patriot units.

Combat Radio Net Operations

Command communications use the UHF system as the primary means of communications. SINCGARS is allocated to the Patriot battalion staff to operate in the AD brigade FM command and FM admin/log nets. Distance may be a constraint, in which case UHF multichannel and or MSE via MSRT/VRC-97 is used.

INTERNAL COMMUNICATIONS

Internal communications are established with each Patriot FU to support the battalion command function. Internal communications also facilitate control of the air battle, administrative, intelligence, operations, and logistics functions, using UHF multichannel and VHF-FM nets.

Multichannel Radio Systems

Patriot battalions use organic resources to establish a multichannel radio system to each subordinate battery. When collocated, an FU can connect via specialty cable directly to battalion. The C2 structure is heavily dependent upon communications for efficient operations. To pass real-time air battle and air traffic information, automatic data links must be established. An example of a multirouting scheme is shown in Figure G-2.

To effectively fight the air battle, each FU needs three UHF circuits. One channel on each radio is used for the multirouting of data on the automatic data link circuit. Normally, for standardization, channel four is used. An engagement voice circuit, called ADC, is established using channel one and party line one. An intelligence and radar reporting (IRR) circuit is established using channel two and party line two. An additional circuit is established using channel three and party line three. This is a maintenance circuit and is not used for control of the air battle. Patriot battery TCAs and battalion TDAs use the ADC net. Patriot battery TCOs and battalion TDs use the IRR net.

Battalion Command FM Net

The purpose of this net is to provide communications for the command function within the battalion headquarters. Each station operating in the net is shown in Figure G-3. This is used as the primary C2 net during movements and as a secondary net when in a static location.

Administration, Intelligence, Operations, and Logistics

Normally, the UHF system which provides communications for control of the air battle also supports other functions. Since the UHF system is operational most of the time, it is also the primary means for the staff to provide C2 of the FU. The total number of circuits is limited by the 12 external wire connections at the ICC. These 12 circuits must provide connections to brigade and each battery. Generally, each battery has a minimum of one circuit and will frequently have more than one circuit. These UHF circuits are connected to switchboards at the battalion and battery.

Patriot battery and battalion communications operators use the maintenance net. This circuit is an unsecure channel used to coordinate communications circuits. This circuit is similar to other circuits between the battalion and the ADA brigade.

The ICC is linked to the BTOC and the system maintenance center by wire (see Figure G-4). This net allows for rapid communications between key elements of the TOC and the ICC. It can be used to cross-tell time-sensitive air battle data such as a change in the airspace control order (ACO). Maintenance support can also be requested without leaving the ICC.

The battalion wire net is shown in Figure G-5. This net is the primary means of communications between battery elements. The switchboard also provides access to a minimum of one circuit to each FU.

A UHF link provides administrative and logistics C2 (see Figure G-6). The net control station is located at the S1 and S4 van. Every station in the net is secure. The net is routed through the ICC with UHF links to higher and supported units.

BATTERY COMMUNICATIONS REQUIREMENTS

The communications system for a Patriot battery is composed of three elements. These elements are the C2 net, data net, and the wire net.

FIRE UNIT COMMAND FM NET

The purpose of this net is to provide communications for the battery command function (see Figure G-7). The net control station is the battery CP. This net is primarily used during unit moves. When the battery is emplaced, the VHF-FM net is used as a secondary means of communications.

FIRE UNIT OPERATIONS NET

The FU operations net is used for C2 of the fire unit when emplaced (see Figure G-8). The net control station for the battery operations net is the CP. All elements in the net are connected by wire lines. A switchboard at the CP provides a means of control for the battery commander.

PATRIOT BATTERY DATA NET

Fiber-optic cables link the ECS to the launching stations. This is to launch missiles and to establish availability and status of missiles. Data radio transmissions are used as backup. The net is controlled at the ECS by special purpose radio equipment which provides reliable transmission of low-data rate messages over a short path (see Figure G-9). All command messages originate at the ECS, requiring a slaved response from the LS in the form of a status message. The LS cannot originate data communications. This is the first net established during battery emplacement.

BATTERY COMMUNICATIONS LAYOUT

The battery wire communications are shown in Figure G-10. Wire is the primary means of communications between elements of the battery. FM radios are used only during movement and until the wire net can be established. A minimum of one circuit to the battalion is available at the switchboard. Normally, the wire lines to the LS connect to ground defense positions.

PATRIOT COMMUNICATIONS PLANNING

Patriot communications consist of radio relay terminals (RRTs), RLRIUs, communications patching panel, corner reflectors, AMG, and amplifiers. These items are used to carry out the battalion's communications plan. See appropriate technical manual for a functional description of these items.

PLANNING RESPONSIBILITIES

The signal officer, in conjunction with the S3, coordinates with brigade staff and adjacent battalion signal officers in developing the communications plan prior to each move. A well-developed communications plan minimizes confusion and indecision during moves. The signal officer prepares the communications plan using the CE annex to the TSOP and the SOI. Frequency management personnel can assist him in developing several areas of the plan.

PRIMARY CONSIDERATIONS

When developing the communications plan, the signal officer considers a number of factors. This list is not exhaustive and will vary depending on the situation. The signal officer considers the following actions:

PLANNING THE COMMUNICATIONS NETWORK

Communications network planning requires close coordination between the signal officer and the S3 section. The S3 informs the signal officer of proposed unit locations determined by the RSOP. The signal officer determines the need for CRGs based on the distance between units and the terrain. Once the UTM coordinates of the deployed units are known, the locations are plotted on a map to determine profile elevations and verify distance between units. Detailed system planning guidance is provided in TM 11-5820-540-12. The same information displayed on the battalion UHF link diagram (see Figure G-11) will be required in a Patriot three- to six-battery configuration. The diagram should contain the UTM coordinates and elevation data for each ECS, ICC, and CRG.

STANDARDIZATION

Standardization of communications tasks is essential for rapid system emplacement and operations. To the maximum extent possible, basic and redundant communications functions should be standardized.

Communications Patching Panel

Standardization at the CPP is achieved by the way voice party lines and data channels are patched. Party line 1 is patched to channel one; party line 2 is patched to channel two of whichever RRT is being used. Data channels within the battalion will be patched from RLRIU port 1 to channel three of RRT 1, from RLRIU port 2 to channel four of RRT 2, and so forth. This process will continue until all patching is complete.

Data Channels

One of the first 11 channels should be dedicated for intrabattalion data transmissions. Channel 12 should not be used for data transmission since a synchronized pulse is routinely sampled from this channel. However, channel 12 can be used for voice transmissions.

EXTRABATTALION AND INTERBATTALION COMMUNICATIONS

The five modems at the ICC and CRG are used for communications with brigade and interbattalion communications with adjacent units. Standardization is achieved by assigning, for example, modem 5 to channel 5 of whichever RRT is being used by the ICC or the CRG. Direct linking provides an alternative to the use of modems for interbattalion data communications. This process increases data throughput and provides data flow between lateral ICCs when modem hardware is unavailable. Up to six direct links can be established during initialization. For example, at initialization, the special direct link source codes to be accepted from battalion B over a direct link are set in the battalion A RLRIU. All data packets originating in battalion B will flow over any direct link antenna path established between the two battalions. Only those data packets carrying the authorized data link source codes will be relayed into the battalion A net and passed into the battalion A computer by the ICC's RLRIU.

At battalion B, the same special direct link source codes are used in the RLRIU. Therefore, packets from battalion A carrying the authorized direct link source codes will also be relayed into the battalion B net and passed into the battalion B computer. A battalion net may also act as a relay between two other battalions using direct linking (see Figure G-12).

Party Line Loops

The party line loops switch located on the front of the CP is also part of communications standardizing. It must remain in the NORM position at all FUs and in the OPEN position at the ICCs and CRGs.

Radio Relay Terminal

Use the same RRT at both ends of the link; for example, RRT 1 at the ICC to RRT 1 at FU 1. By setting up links in this manner, troubleshooting the links using the communications fault data tab at the ICC is made easier.

DEVELOPING DATA LINK NETWORK

In developing the data link network, the signal officer uses the G2, ICC, and CRG deployment FU communications assignment to designate communications links, antenna azimuths, unit ID codes, and CRG locations. Tab 62 is used to assign data and voice partners and is accessible during tactical operations. Tab 62 has been expanded to two pages to allow the addition of six FUs, additional communications links, and antenna azimuths.

The FUs, the ICC, and the CRGs are shown in a 360-degree perimeter (see Figure G-11). The distance from a unit to its perimeter represents 20 kilometers (half the nominal communications planning range). In determining whether units can communicate with each other, the individual observes the situation display and notes the proximity of the units to one another. If the symbols touch or overlap each other, they should be able to communicate without having to relay through a CRG. This assumes that the AMG is used and LOS exists. If the unit symbols do not touch (the overall separation is 40 kilometers or more), a CRG is required.

INITIALIZATION

When a communications plan is developed, it must be implemented. Operators at the ICC, CRG, and ECS use the previously discussed link diagram and the communications planning work sheet as guides in their emplacement procedures.

Once the system is initialized, the operational software monitors and checks the RRTs, RLRIUs, and modems at all units (ECS, ICC, and CRG). This information is displayed at the ICC in the communications link fault data tab. The tab, when used with the battalion UHF communications link diagram, is an excellent tool in determining link and equipment status. The information in the tab becomes available when data communications are established between links (RLRIU to RLRIU).

DATA LINK CONSIDERATIONS

Patriot data communications is defined by or limited to the 32 kbps UHF multirouting network. Each linked unit, depending on its data protocol and initialized linkage, uses (loads) a portion of that capacity. If but only a "moderate" number and combination of units (Note: Far less than the maximum number and combination allowed by PDB-3 [Block II] ICC software) are interfaced via the UHF net to the ICC, the net loading capacity of 32 kbps (or 100 percent) can be exceeded.

In the ICC, as a PDB-3 software improvement, the network loading is automatically calculated and displayed for currently linked units as a percentage value in Tab 02.

For planned deployments, this percentage, referred to as the deployed net loading percentage (DNLP) is also calculated and displayed in communications Tabs 67, 68, and 69.

In the ICC, also as a PDB-3 software improvement, data communications can be accelerated between ICCs by initializing a "direct-link." A direct link (up to five are possible) bypasses modem hardware and fully accesses the 32 kbps net capacity.

Data modems located only at the ICC and CRGs, five each per shelter, are required for data communications with ATDL-1 and TADIL-B units; for example, brigade TOC, HEU, GEHOC, CRC, and auxiliary (see Figure G-13).

TACTICAL CONSIDERATIONS

Patriot communications via UHF are subject to degradation under combat conditions. The following are procedures to help reduce the amount of degradation.

System Loading Reduction Measures

Given DNLP > 100 percent, to maintain optimum system performance, the ICC will automatically degrade gradually its data communications to Patriot FUs first and then to or with CRG modem-ported Hawk fire units (if linked). The number of messages on the link(s) to FUs will be reduced and lower-priority messages for FUs will not be serviced as often. Note: Engagement and engagement-related commands are high-priority messages.

Operator Loading Reduction Measures

Given an overloaded net (DNLP > 100 percent), the ICC operator will be alerted and can take the following actions:

RECOMMENDATIONS

The following are some basic rules for UHF communications carrying data (additional information can be found in FM 44-85-1 [TBP]):