Air Fronts: Air Defense FM 44-8; Antiaircraft Operations Room and Antiaircraft Artillery Intelligence Service - Chapter 3. AAOR and AAAIS for Gun Defense
Section I. GENERAL
59. GENERAL. a. For the purposes of this chapter a defense composed of one AA gun battalion is assumed. The battalion is equipped with five radars.
b. In a defense composed solely of AA guns the responsibility of furnishing a continuous AAAIS must be assumed by the gun units themselves. The battalion commander will establish an AAOR. An AAAIS for reporting all targets must be formed from the personnel of the gun defense. The AAAIS organization will consist of personnel manning radars and of personnel manning outlying observation posts.
Section II. ANTIAIRCRAFT OPERATIONS ROOM
60. LOCATION. The battalion AAOR is located in accordance with the principles outlined in paragraphs 12-14.
61. EQUIPMENT. a. AA operations board. It is suggested that the operations board he a table approximately 8 by 8 feet. For convenience in transporting this can be broken down to four tables. On the table is spread a map or a sheet of drafting paper, covered completely with some transparent material. The defended area is in the center. Gun positions, observation posts, the grid in use, and the most prominent terrain features are also shown. A scale of 1 inch = 2,000 yards is suggested. This will permit plotting targets to the maximum range of the radars. (See fig. 1.)
PERSONNEL
1 Switchboard operator. 7. Situation board operator.
2, 3, 4, 5, 6, 8. Plotters. 9. Plot observer. 10. AA operations officer.
Figure 10. Typical AAOR gun battalion (radios are not shown as it is assumed they are remotely operated).
b. Situation board. The situation board is similar to the operations board. It is smaller, is hung vertically, and is used to display early warning information. The situation board has a smaller scale and covers more area than the operations board. It should extend the radius from the center of the defended area to the limit of the early warning range.
c. Status board. See paragraph 18 and figure 2.
d. Platform. A platform about 4 feet square and 30 inches high is required for the use of the AAOO and plot observer. The stand should be equipped with a writing desk. (See fig. 10.)
e. Communications. Communication equipment includes switchboards, radios, and the necessary telephones and head and chest sets.
f. Miscellaneous. Miscellaneous equipment includes: chairs, lights, AAOR operations journal, display stands, arrows, grease pencils, and tabs to display information about the targets.
62. PERSONNEL. a. General. Enlisted personnel to operate the AAOR will be taken from personnel within the battalion, normally from the operations and intelligence and communication sections of battalion headquarters battery.
b. AA operations officer. The AAOO is the representative of the battalion commander, and supervises the operations in the AAOR during his tour of duty. He evaluates all information received in the AAOR. He orders changes in the state of readiness. He insures that all batteries receive prompt warning of any attack. He restricts or releases fire as necessary based on information from the AAAIS, higher head-quarters, or appropriate air force operations room. He issues orders for the direction and coordination of the fire of the entire defense in all cases not covered by SOP.
c. Plot observer. The plot observer, assistant to the AAOO, is the senior non-commissioned officer on duty. He alerts the batteries and directs changes in the state of readiness as ordered by the AAOO. He relieves the AAOO of as many as possible of the routine duties required to insure execution of his orders. He is responsible for the status board being posted. He records in the AAOR operations journal all actions, changes of state of readiness, and all orders received or issued by the AAOR. He supervises all checks made on the communication nets.
Figure 11.
Typical AAOR operations journal.
d. Radio operators. Radio operators are responsible for the proper tuning, operation and maintenance of the radio. Each carries out the hourly schedule of checks with the other stations in his net. Each monitors the nets and enforces strict radio discipline. They execute such other duties as directed by the AAOO.
e. Switchboard operator. The switchboard operator is responsible for installation, operation, and maintenance of the switchboard. He makes periodic checks. He monitors the wire nets and enforces strict telephone discipline. The switch-board is set up as close as possible to the AAOO. He executes such other duties as directed by the AAOO.
f. Plotters. Six plotters (five radar plotters and one OP plotter) at the operations board plot the locations of targets as they are reported to them from the radars or the OP's. They erect stands displaying information about the targets they are plotting. An additional plotter, for the situation board, plots the early warning location of targets. One plotter is assigned to each radar "on the air." In some cases it may be possible to assign more than one radar to each plotter.
Section III. AAAIS
63. GENERAL. The radars of the defense are supplemented, when necessary, by outlying OP's to form the battalion AAAIS. The personnel to man the OP's are taken from the various batteries. OP's are connected by wire to the nearest radio transmitter operating in the AAAIS net. If the establishment of wire lines is impossible, the radios allotted to the lettered batteries or battalion headquarters may be used. It is very desirable that the radios remain with the battalion and batteries, but if the need for OP's is particularly urgent, this shift of equipment may be necessary.
64. OP's. For discussion of location and operation of OP's see paragraphs 38 and 44.
65. RADARS. a. The radars send in reports on all targets in terms of grid coordinates. The PPI tube of the radar is gridded with the grid used on the operation board. (See par. 66.) Plots are read from the PPI scope and reported to the AAOR as rapidly as practicable or at intervals as requested by the AAOR. (See par. 69.) If there is no PPI scope on the radar the present position data of the targets are obtained from the selsyns in the battery CP. (See par. 68.) These data are converted to grid coordinates and transmitted to the AAOR.
b. If radars are assigned normal sectors of search greater than 1600 mils, it may be advantageous to use the automatic search features of the radar and scan through 6400 mils. SOP must state whether radars will report targets "picked up" outside of assigned sectors. The normal procedure will be for radars to report all targets to the AAOR until directed by the AAOO to discontinue reports on specific flights or in specific sectors.
66. GRIDS FOR PPI SCOPES. a. The PPI scope of the SCR-584 is gridded each time the radar position is changed. The PPI scope of the radar assigned to a gun battery is gridded for the 35,000-yard scan. The PPI scope of the battalion headquarters battery radar is gridded for the 70,000-yard scan.
b. For construction and application of grid to PPI scopes see appendix II.
67. CONVERSION BOARD. a. A conversion board is constructed for use at each radar with a PPI scope. Grids for both the 35,000-yard and the 70,000-yard scans are superimposed on the board using distinctive colors.
b. This board is used at the radar to convert plots read from the PPI scope to true coordinates. For example, if the radar is being used on a 70,000-yard scan and its PPI scope is gridded for the 35,000-yard scan, the plot is transferred to the conversion board by reference to the 35,000-yard grid. The correct coordinates are read from the board by reference to the 70,000-yard grid. (See fig. 12.)
Figure 12.
Conversion board.
c. For construction details of conversion board see appendix II.
68. REMOTE DATA INDICATOR. a. Batteries having radars with no PPI scope read present position data from the remote data indicator in the battery CP. The data are plotted on a battery plotting board (see FM 4–121) and converted to grid coordinates for transmission to the AAOR. This method of obtaining and reporting data is also used during early stages of an operation until such time as the PPI scope can be gridded.
b. If the battery is issued no remote data indicator, but spare selsyns are available, a remote data indicator is constructed capable of receiving coarse azimuth, elevation, and slant range. To permit the proper employment of this indicator, a modification is made at the radar. This consists of the attachment of a 19-conductor ordnance plug to the data trans-mission system of the radar, so that coarse azimuth, elevation, and slant range can be transmitted over one cable while present position data are being transmitted to the normal fire control instruments of the battery also. A sketch of the remote data indicator is shown in figure 13. See TB SIG 38 for details of construction. The dials are graduated in 10-mil units for both azimuth and elevation and 100-yard units for slant range. If a remote data indicator is not employed, it will be necessary for Ao, Eo, and Do readers to transmit data over telephone lines from the radar to a battery plotting board.
Figure 13.
Remote data indicator.
c. See paragraph 82 for a discussion of another type of remote data indicator.
69. REPORTS FROM RADARS. a. Using gridded PPI. (1) When the radar is on surveillance, reports are made on each target appearing on the PPI scope. Assume that the radar is searching using PPl scan with the range selector switch set for the maximum range of 70,000 yards. The PPI operator reports:
"Baker Able" (code name of position).
"Target 10+" (estimate of number of planes). "26–44" (grid coordinates of the target).
"IFF Clear" ("IFF Unknown," "No IFF").
(2) If a radar in the defense other than the battalion headquarters battery radar is being used for surveillance, the initial reports on targets beyond 35,000 yards are converted to grid coordinates using the conversion board. (See par. 67.)
(3) Radars on surveillance furnish altitudes whenever requested by the AAOR.
(4) When gun battery radars are tracking targets with the 70,000-yard scan, the coordinates are converted using the conversion board. When the target comes within 35,000 yards, the PPI scan is switched to the 35,000-yard scan and grid coordinates are read directly without reference to the conversion board.
(5) Gun battery radars tracking targets report coordinates to the AAOR at intervals as directed. Altitudes are transmitted every minute.
(6) Gun battery radars tracking targets give initial report as in (1) above. Subsequent reports consist only of coordinates and altitudes.
b. Using remote data indicator. Present position data are read from the selsyns in the battery CP on all targets tracked by the battery radar. The data are plotted on a battery plotting board, converted to grid coordinates, and transmitted to the AAOR. Reports are made as frequently as practicable or as directed. The reports are made as in a above.
Section lV. COMMUNICATIONS
70. GENERAL. The particular situation will determine the exact type and extent of the communication set-up to be used. The general rule to be followed is that the AAOR and AAAIS must rely on radio communication in the early stages of all tactical operations, changing to wire as time and local conditions permit. In a static defense, wire will be the backbone of the communication system. When the gun battalion is being used in mobile situations, most of the communications will have to be by radio.
71. COMMUNICATION FOR STATIC DEFENSE. a. Primary net. (1) Two wire lines are laid to each battery and to the site of the battalion headquarters battery radar. The first line is a data line running from the radar through the CP of each position to the corresponding plotter in the AAOR. The second line is the command and intelligence line. (The latter line will probably have to be used for administrative matters during slack periods.) The command and intelligence net is a "hot loop" from the AAOO and plot observer in the AAOR to every battery and to the battalion headquarters battery radar. The phones are manned 24 hours a day so that connection between them is instantaneous without the necessity of ringing. When time permits and the additional necessary wire is available, the command and intelligence lines are run directly to the AAOR and the "hot loop" is established by cord connections at the switchboard. (Sec fig. 14.) If sufficient drops are available, the data lines are run through the switchboard. This adds to the flexibility of the system.
(2) For communication to OP's, see paragraph 63 and figure 14.
b. Secondary net. In the event of failure of wire communication, the radio nets must be used. Intelligence is broadcast over the AAAIS net with reception at the batteries by the SCR-593's. Data from the batteries must of necessity flow over the command radio net to the AAOR. Command and administrative matters can flow over either the AAAIS net or the command net. The radio set at the AAOR being the net control station can break in and send the necessary messages.
Strict radio discipline must be enforced or the communications will bog down.
Figure 14.
Schematic primary wire and radio nets gun battalion. (Number of
OP's will vary with situation. Command radio net not shown.)
72. INITIAL COMMUNICATION NET FOR AAOR. a. Communications for an AAOR must be put into operation as soon as the battalion moves into a new position. At the outset, radio is used exclusively. The radio nets described in paragraph 71b are initially used. No observation posts, other than air guards in the immediate vicinity of the batteries, are established until at least one wire circuit is laid to all batteries.
b. Data reports by radio from the batteries are broadcast over the command radio loud speaker in the AAOR. As successive reports are received, the plotters pick out the reports from their particular battery and plot them on the operation board.
Section V. OPERATION
73. OPERATION BEFORE TARGET PICK-UP. a. At OP's. One observer at each OP is constantly searching the sky in his sector for aerial targets. Information on any targets seen by the observer is transmitted immediately to the AAOR by the communication means available.
b. Surveillance radar. At least one radar in the battalion is always "on the air." The five radars in the battalion alternate as the surveillance radars. The radar on surveillance duty is manned according to SOP, ready to report on all targets over the data line to the AAOR. (See par. 69.)
c. AAOR. The status board is continuously posted. A plotter is connected by telephone to the surveillance radar. The situation board plotter is at his post ready to plot early warning information. The OP plotter is ready to plot data received from the OP's.
74. ACTION UPON TARGET PICK-UP. a. By the surveillance radar. A target picked up by the surveillance radar is reported immediately to the AAOR.
b. By OP. A target picked up by an OP is reported immediately to the OP plotter.
c. At AAOR. Reports received from either the surveillance radar or an OP are plotted on the operation board by the appropriate plotter. The plotter immediately prepares the display stand and places it beside the plot in such a position that it can be readily seen by the AAOO. Any reports received from early warning agency are plotted on the situation board or operations board depending on their range. Plots are evaluated and pertinent information is passed on to the units of the AA defense. Full manning details in the AAOR are ordered.
75. ACTION WHEN TARGET IS IDENTIFIED AS HOSTILE. a. When targets have appeared on the situation or operations board and a raid seems likely, the AAOO alerts all batteries, using the command and intelligence net. He gives them the location of the target or targets in grid coordinates, and any pertinent information about the target which is already available. All radars go "on the air" upon receipt of this warning. If necessary, while the battery radars are getting on target, the plot observer gives them subsequent reports in grid co-ordinates. The batteries plot this information on a plotting board.
b. The AAOO watches the target plot on the situation board as it approaches the area covered by the operations board. As soon as the target is within range of the operations board, it is transferred from the situation board to the operations board. The AAOO notes which battery radars are on target, as reported by the batteries. The AAOO, using the command and intelligence net, orders the radar of the battery to whose sector the target is closest, to commence reporting the grid co-ordinates of that target to its plotter in the AAOR. (It may be advisable for the plotter to do this himself, using his data line, when he is so directed by the AAOO.) The plotter plots the information coming over the data line and erects a stand showing information on the raid.. The other batteries continue to track or search according to existing SOP and instructions from the AAOO. If the battery radar should lose the target, it will report "Off target" to the plotter at the AAOR. Upon receipt of this information, the AAOO may order another radar to start sending plots.
c. The surveillance radar continues searching and reports plots on all targets. The plotter at the AAOR disregards those reports duplicating reports from battery radars.
d. Often one of the battery radars will be performing surveillance duty. When alerted, the battalion headquarters battery radar automatically takes over the task of surveillance, notifying the AAOO through its plotter in the AAOR when it starts searching. Then the AAOO releases the battery radar, which had been on surveillance duty, to the battery.
e. In the case of multiple attacks the AAOO studies the plots of all targets and evaluates them. If necessary he will exercise fire direction so as to insure proper distribution or concentration of fire on appropriate targets.
f. It may occur that two or more plotters in the AAOR are plotting the same target. The AAOO will determine which plotter should continue to plot the target. The other plotter, over the data line, requests that no more plots be sent him on that target.
g. Assume that all batteries are engaging targets. All may be engaging the same target or engaging individual targets. The surveillance radar, or an OP, reports the appearance of a new target, which, in the opinion of the AAOO, offers a more dangerous threat to the defended area than one or more of the targets already being engaged. The AAOO, over the command and intelligence net, orders one or more batteries to cease tracking their present target and to pick up the new target. The procedure in b and c above is then repeated.
h. The fire direction exercised by the AAOO should be covered, as far as is practicable, in SOP. In the cases where SOP does not apply, the orders of the AAOO must be clear, concise, and brief so as to prevent delay and confusion. It is to be noted that the conduct of fire and technical fire control are left to the firing batteries' commanders. The AAOR has completed its mission when the various radars are accurately tracking the targets assigned to them, a visual record of the course of such targets is being maintained on the operations board, the necessary commands and intelligence have been passed to the fire units, and the AAOR is alert to cope with any additional targets which may menace the objective being protected by the gun defense.
