DIGITAL MESSAGE DEVICES
DIGITAL MESSAGE DEVICE AN/PSG-2A
| This section implements STANAG 2934, Chapter 13 Annex A and QSTAG 503. |
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B-1. OPERATION OF THE DIGITAL MESSAGE DEVICE
a. Description. The digital message device AN/PSG-2A is a small, rugged, lightweight, portable, two-way communications terminal. It is used by FA observers to transmit and receive high-speed digital messages. The DMD can communicate with the tactical fire direction system (TACFIRE), the BCS, the FIST DMD, the mortar ballistic calculator (MBC), and other DMDs through wire or radios. Mnemonics used with the DMD are listed and interpreted in Tables B-1 and B-2 at the end of this appendix (B-31 and B-32).
b. Data Entry and Message Composition. Information is entered into the DMD, and messages are composed by means of a keyboard and a display located on the front panel. Data entry menus and message formats are presented in an easily understood manner. Information is entered by using a step-by-step procedure. The DMD prompts the operator for proper entries by displaying all possible choices for each data or message element. Entries are made as direct data or as a multiple-choice selection from a displayed menu. Illegal entries are prevented. Completed data entry menus and messages are displayed for operator viewing so that errors can be identified and corrected. Some fields contain preset default values. The default is assigned if the operator selects no other value for that field.
c. Memory Capacity. The DMD memory has several buffers and files:
d. Functional Sections. The DMD AN/PSG-2A has four functional sections as shown in Figure B-1.
Figure B-1. DMD FUNCTIONAL SECTIONS
Figure B-2. DMD INDICATOR LAMPS
Figure B-3. DMD CONTROL SECTION
Figure B-4. DMD KEYBOARD SECTION
(4) Interface Section. The interface and power connectors (Figure B-5) are located on the top left side of the DMD rear case. Their functions are described below.
Figure B-5. DMD INTERFACE SECTION
e. Audible Tone. The DMD has an audible tone, or beep, which can be made to sound when a message is received and/or when a key is pressed. It can be set at different intensity levels. The audible tone sounds one time per second for regular messages, two times per second for ACK and NAK messages, and four times per second for FO CMD messages.
Before the DMD can send and receive messages, it must be prepared for use. Preparation includes the procedures discussed below.
a. Assembly. The manner in which the FA observer assembles his DMD is determined by the tactical situation, the observer's mission, and his method of operation.
(2) Mounted Operations. During mounted operations, the DMD may be installed in its carrying case or it may be removed. In either configuration, the observer must position the DMD where it can be readily used. It must be secured and protected to prevent damage during vehicle movement. The DMD normally is powered by a vehicular power source and is connected to a vehicular radio.
b. Memory Purge. The DMD memory may be purged. Purging deletes all previously stored information in the DMD status menu, authentication code file, received message buffers, off-line compose message files, and active mission buffers. Any message or data element having a default will, be assigned that default value. The memory normally is purged only when it is necessary to completely reinitialize the DMD or under emergency conditions to prevent enemy access to stored information.
c. Diagnostic Checks. The DMD has built-in test circuits which enable the operator to determine the operational status of the DMD. Diagnostic checks may be made anytime. They should be made when preparing the DMD for use.
(2) Keyboard Test. When the display and indicator lamp test is completed, the DMD is placed in a special keyboard test mode. The proper functioning of each key can be verified at this time.
(3) Operational Check. The communications interface may be checked for proper function by the operational check.
(4) Message Bell Volume Test. The message bell volume may be set and tested.
d. Initial Status Selection. The status menu is used to establish certain communications parameters, DMD functional characteristics, and battery condition information. Most of the data fields have default values. The fields are discussed below.
(2) DEST. This field is used to establish the destination to which messages will be transmitted. The unique address of the receiving device (TACFIRE, BCS, FIST DMD) is entered in this field. No default value is assigned.
(3) T/D. This field is used to indicate whether a message transmitted from the DMD is a test message or contains data. Data is the default value.
(4) XMT BLK. This field is used to select the transmit block mode employed by the DMD. If SNG is selected, then the message contents are transmitted once. If DBL is selected, the message contents are automatically transmitted twice. The single block mode is the default value. The transmit block selected is dictated by unit SOP or tactical conditions. The double block mode may be specified during periods of heavy radio interference or jamming. The DMD block mode must match the block mode specified in the destination device.
(5) XMT RATE. This field is used to specify the rate at which the DMD will transmit and receive messages. 600 or 1,200 bits per second may be selected; 1,200 is the default value. The transmit rate selected is dictated by unit SOP or tactical conditions. The DMD transmit rate must match the rate specified in the destination device.
(6) PREAMBLE. The DMD must key the radio or wire circuit before transmitting a message, just as radio operators must do. The preamble field specifies the amount of time the radio or wire circuit is keyed before message transmission. A value between 0.1 and 4.0 seconds may be specified; 2.2 seconds is the default value.
(7) AUTH GROUP NO. This field is used to indicate the current group of authenticators. Group number 00 is the default value.
(8) AUTH LINE NO. This field is used to indicate the line number of the authenticator pair that will be sent with the next message transmitted from the DMD. Line number 01 is the default value.
(9) DSPL DLY. This field is used to specify the time the DMD will wait from the last data entry until the next display is presented. A value between 0.0 and 2.0 seconds may be specified; 0.4 second is the default value.
(10) KBD BELL VOL. An audible tone can be made to sound when a key is pressed. The volume is set by selecting a value from 0 (completely off) to 7; 0 is the default value.
(11) MSG BELL VOL. An audible tone can be made to sound when a message is received. The volume is set by selecting a value from 0 (completely off) to 7; 0 is the default value. This field is also used to conduct the message bell test.
(12) WATT HRS. The DMD counts and displays the number of watt hours of power consumed from the internal battery. WATT HRS should be set at 00.0 when a fully charged battery is installed. There is no default value assigned.
(13) BATT LMT. This field is used to indicate the total number of watt hours of power the operator believes the internal battery can produce. The DMD compares the values in this field and in the WATT HRS field to alert the operator to battery weak and battery required conditions. There is no default value assigned.
e. Entry of the Authentication Code List and Operator's Key.
(2) The operator's key is also stored in the DMD authentication code files. See subparagraph B-5a(1)(a) for information on the operator's key.
f. Establishment of Digital Communications. Once the DMD has been prepared for use, digital communications must be established with the destination device. Normally, voice communications are established first to ensure that all radios are operating and are properly set or to ensure the wire circuit is complete. Once this has been done, a FREETEXT message is transmitted to ensure that communications parameters have been properly set and that the DMD can transmit and receive.
The DMD can transmit and receive 20 preprogrammed, fixed-format message types which are divided into five categories as discussed below.
a. Standard Fire Requests. Standard fire request messages contain all the information in a conventional call for fire:
They are used by observers to initiate fire missions. The five standard fire request messages are as follows:
b. Adjustments. Adjustment messages contain all the information required for the adjustment of fire. The three adjustment messages are as follows:
c. Registrations. Registration messages are used in observing a precision, an HB or MPI, or a radar registration. The three registration messages are as follows:
d. Intelligence. Intelligence messages are used to report enemy locations and other information of intelligence value. The three intelligence messages are as follows:
e. Information. Information messages can be transmitted and received by the DMD. The six information messages are as follows:
B-4. MESSAGE COMPOSITION, STRUCTURE, AND FLOW
Messages may be composed in the active mission buffers or in the off-line compose message files.
a. Message Composition in Active Mission Buffers. The active mission buffers, M1 and M2, are used to transmit messages and conduct fire missions. They permit an observer to conduct two simultaneous missions from the DMD, one in cach active mission buffer. Messages must be composed in an active mission buffer or be transferred from an off-line composed message file into an active mission buffer before they can be transmitted.
b. Message Composition in Off-Line Compose Message Files. A message composed in one of the seven off-line compose message files, F3 through F9, may be stored there until transmission is des red. This enables the observer to anticipate future requirements and to prepare messages in advance of their use. Messages stored in the off-line files must be transferred into an active mission buffer before they can be transmitted.
c. Message Structure. A DMD does not transmit messages as they appear to the operator. They are transmitted as a string containing 44 alphanumeric characters. Each DMD message is composed of two parts: the header and the body. The header uses six character positions. The first position of the body designates the message type, and the rest of the body can use up to 37 characters.
Figure B-6. DMD MESSAGE HEADER
(c) An authenticator pair is used in conjunction with the try number to provide message self-authentication. The operator can store a group of authenticator pairs in the authentication code file and cause the DMD to transmit them in order. If the operator has not previously stored authenticator pairs, he may enter them through the keyboard during message composition. In either case, the two alphanumeric characters are inserted into positions 3 and 4 of the message header.
(d) The entry in position 5 indicates whether the message contains data or is a test message. The DMD extracts this information from the T/D field of the status menu.
(e) The unique address of the DMD is inserted in character position 6. The DMD extracts this alphanumeric character from the ORIG field of the status menu.
(2) Message Body. Character position 7, the leading character of the message body, indicates the type of message being transmitted. The remaining 37 characters compose the text of the message. The DMD uses an encoding scheme which automatically converts a composed message into a string of characters. Upon receipt, the destination device decodes the character string and displays the message in a format the operator can read and understand. Each message type uses a different encoding scheme, which is identified by the character in position 7. The entire process of encoding and decoding is not apparent to the DMD operator. It is done automatically by the DMD.
d. Message Flow. When a DMD, FIST DMD, FED, TACFIRE computer, VFMED, or battery computer unit (BCU) receives a digital message, it automatically transmits a brief digital response called an ACK message. The TACFIRE computers can automatically verify message authenticity. When TACFIRE receives a properly self-authenticated message, it transmits an ACK message. When TACFIRE receives an improperly self-authenticated message, it transmits a NAK message. The DMD display shows that an ACK or a NAK message has been received, and the ACK and NAK indicator lamps flash. The operator can clear these indications by pressing the X key. When a NAK has been received, this action causes the AUTH LINE NO field of the status menu to be reset, thereby resynchronizing the DMD with TACFIRE. The other devices cannot automatically verify message authenticity, and they will always transmit an ACK message if a DMD message is received. If neither the ACK nor the NAK light flashes, the destination device did not receive the message.
Deception is a form of electronic warfare which might be used against automated FA systems. An enemy force may try to transmit messages which imitate the digital transmissions of legitimate subscribers on the fire direction nets. If TACFIRE or BCS were permitted to process deceptive messages, the enemy could direct artillery fires on friendly positions or input false intelligence information. If FA observers accept deceptive messages as autherltic, the enemy could give them erroneous tactical information or direct them to take improper actions. The authenticity of received messages must be determined to counter the electronic threat. This may be done by using the self-authentication or challenge and response technique.
a. Self-Authentication. Self-authentication is the preferred method of authenticating digital messages, because all required information is transmitted in the message header. Several requirements must be met for this technique to be used. First, the transmitting station must have a current group of authenticators. The DMD operators are issued code books which contain the authenticators they must use. Second, the receiving station must be able to compare the transmitted authentication information with that which should have been transmitted. The DMD destination must, therefore, have a copy of the DMD operator's authenticators. Likewise, the DMD operator must have a copy of the destination codes. Third, the transmitting and receiving stations must be synchronized. Each must know which authenticator pairs have been transmitted and which should be transmitted next. The DMD operator can do this by marking through the codes in the reception code book as messages are received. The DMD can keep track of the codes used for transmission.
(b) Input Directly From the Keyboard. At times, it may not be possible or desirable to retrieve authenticator pairs from the authentication code file. In these cases, the proper codes are not on file and they must be entered directly from the keyboard. To do this, the DMD operator displays the message AUTH field. He then opens his authentication code book, turns to the current group, and identifies the authenticator pair associated with the next line number to be transmitted. This authenticator pair is entered in the AUTH field. Because the DMD expects the operator key to be entered, an error message will be displayed as follows:
(2) Verifying Message Self-Authentication. If a message is transmitted and no ACK or NAK message is received, the operator should assume that the destination did not receive the message and it must be retransmitted. The DMD increments the value of the AUTH LINE NO field of the status menu. Because the destination is unaware of the attempt of the DMD to communicate, it does not increment the line number of the next authenticator pair it expects to receive. This failure to communicate causes the DMD to lose synchronization with its destination. To enable verification of message authenticity under these conditions, a try (retransmission) number is transmitted with the authenticators in the message header. The try number and the authenticators are used together to determine message authenticity.
(b) Authenticating the First Transmission of a Digital Message. When a message is transmitted for the first time, the try number is 0. The sum of the try number and the next expected line number equals the expected line number. Authentication is done by comparing the transmitted authenticator pair with the one on the expected line.
(c) Authenticating a Message Retransmission. The DMD will permit three retransmissions before it tells the operator to reestablish voice communication with his destination. When a message is retransmitted, the try number has a value of 1 to 3. Consequently, the sum of the try number and the next expected line number is greater than the expected line number.
A is transmitting to B. They are synchronized.
An extract of A's current code group is shown.
LINE NUMBER AUTHENTICATOR CODE
05 SG
06 BZ
A transmits a message to B by using line 05 (try number
= 0 and authenticator pair = 5G). B does not receive the
message.
A retransmits the message by using line 06 (try number
= 1 and authenticator pair = BZ). B still expects to
receive the authenticator corresponding to line 05.
Upon receipt, B adds try number 1 and expected line 05.
The sum is 06. Because BZ is the authenticator pair
associated with line 06, the message is properly
self-authenticated.
b. Challenge and Response Authentication. Normally, a DMD operator is issued one set of authentication code books. These allow him to transmit self-authenticated messages to his primary dejtination. Because of the litnited availability of COMSEC materials, it is unlikely that alternate destinations wiU have a copy. Consequently, it generally is not possible to transmit self-authenticated messages to alternate destinations. Authentication must be done by using the challenge and response technique that is currently used in voice communications. The challenge and response may be transmitted by using FREETEXT messages. It is not practical to authenticate every message in this manner. The DMD operator may be challenged only after his initial transmission and anytime the destination suspects imitative deception. A DMD operator generally communicates with an alternate destination for a limited time. Communications eventually will be reestablished with the primary destination. To prevent exposing the stored authenticator pairs, the DMD operator should enter phony codes by using the direct keyboard input technique. To prevent the loss of synchronization with the primary destination, the DMD operator should note the value stored in the AUTH LINE field of the status menu before destinations are changed. This value must be reentered when communications are reestablished with the primary destination.
If the DMD has been properly assembled and power has been applied, the mode menu (Figure B-7) will be displayed. The mode menu is the DMD's main index--the starting point for all DMD operations. It can be displayed anytime by pressing the MODE key. If the mode menu does not appear on the display panel, then adjust the DSP BRT control knob. It may be necessary to press the MODE key to recall the display. If the mode menu still does not appear, take the following corrective actions:
Figure B-7. MODE MENU
B-7. PROCEDURE FOR PURGING THE MEMORY
The DMD memory may be purged when it is prepared for use or in emergency situations. This prevents enemy access to the stored information. Purge the memory of the DMD 01. as follows:
| NOTE: For diagnostic test procedures, see subparagraph B-2c above. |
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B-8. PROCEDURE FOR MAKING INITIAL STATUS SELECTIONS
Establish communications parameters, DMD functional characteristics, and battery conditions by making initial status selections.
a. Display the mode menu by pressing the MODE key.
b. Note the mode menu entry E=STATUS. Press the E key to display the status menu. Entries must be made in all fields with a question mark (?). All other fields except WATT HRS and BATT LMT have default values.
c. Press the JUMP key to display the ORIG field. Enter the unique address of the DMD.
d. DEST is displayed. Enter the unique address of the destination device.
e. T/D is displayed. Select TEST when transmitting test messages; otherwise, select DATA.
f. XMT BLK is displayed. Select DBL when transmitting through heavy radio interference or jamming; otherwise, select SNG. The DMD XMT BLK must match that of the destination.
g. XMT RATE is displayed. Select 600 or 1,200 bits per second in accordance with unit SOP cr communications instructions. The DMD XMT RATE must match that of the destination.
h. PREAMBLE is displayed. Enter a 0.1- to 4.0-second preamble in accordance with unit SOP or communications instructions.
i. AUTH GROUP NO is displayed. Enter the number of the current authenticator group.
j. AUTH LINE NO is displayed. Enter the line number of the next authenticator pair to be transmitted. If no transmission has been made by using the current group, enter 01.
k. DSPL DLY is displayed. Enter the time (0.0 to 2.0 seconds) a menu or message element will remain displayed after an entry or selection has been made
l. KBD BELL VOL is displayed. Set the keyboard bell volume to the desired intensity (0 is completely off, and 7 is the maximum level).
m. MSG BELL VOL is displayed. Set the message bell volume to the desired intensity (0 is completely off, and 7 is the maximum level).
n. WATT HRS is displayed. If a fully charged battery has just been installed or if no internal battery is presently installed, enter 00.0 watt hours; otherwise, press the V key to select the displayed value.
o. BATT LMT is displayed. Enter the number of watt hours that a fully charged battery can be expected to produce. If no battery limit has been determined by experience, enter 12.0.
p. The completed status menu is displayed. Review the status menu and make corrections where appropriate.
B-9. PROCEDURE FOR STORING THE AUTHENTICATION CODE LIST AND OPERATOR'S KEY
An entire group of 100 authenticator pairs and an operator's key may be stored in the authentication code file by using the procedures discussed below.
a. Display the mode menu by pressing the MODE key.
b. Note the mode menu entry F = AUTH CODES. Display the authentication code file instructions by pressing the F key.
c. Enter the line number of the first authenticator pair to be entered. Normally, this will be 01.
d. Press the X key to enter the authentication code file at the line number specified.
| CAUTION Pressing the X key to enter the authentication code file will delete previously used authenticator pairs. The code beginning with the entry line and continuing to (but not including) the line specified in the AUTH LINE NO of the status menu will be erased. When the file is entered, at least one code (on the entry line) will be deleted. Always enter at line 01. |
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e. Beginning with the entry line and continuing to line 00, extract the authenticator pairs from the current group in the code book, and record them in the authentication code file. Extreme caution must be taken to ensure the codes are stored on the appropriate line and without error.
f. After an entry is made on line 00, select and enter an operator's key. The selected key should be easy to remember. It is used each time a message is composed to cause the DMD to retrieve and transmit the authenticators which have been stored in the file.
B-10. MESSAGE COMPOSITION AND TRANSMISSION
Messages may be composed in active mission buffers, M1 and M2, or in off-line compose message files, F3 through F9. A message can be transmitted only from an active mission buffer. Consequently, a message must be composed in M1 or M2, or it must be transferred from an off-line file into M1 or M2 before it can be transmitted. The paragraphs below discuss composing and transmitting various types of messages.
a. Composing a Message in an Active Mission Buffer and Transmission.
(2) Note the mode menu entry 1 = MSN1 ACTV or 2 = MSN2 ACTV. It indicates the mission buffer in which the message will be composed. To activate the other mission buffer, press the 2 or 1 key, as appropriate.
(3) Note the mode menu entry A = MSG TYPES. Display the message types menu by pressing the A key.
(4) Note the M1 ACTIVE or M2 ACTIVE entry on the message tvpe menu. This indicates the active mission buffer in which the message will be composed. Select the message to be composed, and display its skeleton by pressing the appropriate alphabetic key.
(5) Those fields assigned a default value will have the default displayed. Default values will be transmitted il no other selections or entries are made. Those fields with a question mark (?) require an operator entry before transmission is permitted. Some fields, such as DIR or TGT NO, may have previously specified values displayed. These values are drawn from the mission data portion of the active mission buffer.
(6) The cursor flashes in the AUTH field. Press the JUMP key to display the AUTH field.
(7) The AUTH field permits, the operator to specify the authenticator pair which will be transmitted in the message header. Either of two techniques may be used.
(b) Direct Input From the Keyboard. This technique may be used if the operator has not stored the current group of authenticator pairs. It also may be used if the operator is transmitting to an alternate destination and does not want to expose the previously stored codes. Select the authenticators to be transmitted (not the operator's key), and enter the alphanumeric pair in the AUTH field of the message. This entry will cause an error message to be displayed. Disregard the error message, and reenter the pair.
(8) Compose the rest of the message. The default or previously specified values may be selected by pressing the down arrow key. When entries have been made in all fields, the completed message is displayed for operator review. To make a correction, move the cursor to the appropriate field, and display it by pressing the JUMP key. Correct the error, and display the corrected message by pressing the JUMP key.
(9) Listen to the net. If there is no other traffic, transmit the message by pressing the XMIT key.
| NOTE: The completed message must be displayed before transmission is permitted. |
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(b) If the destination is a TACFIRE computer and it received the message and the authentication was incorrect, a NAK message is transmitted back to the DMD. The display and ACK and NAK indicator lamps indicate receipt of the NAK message. The NAK light flashes at twice the speed of the ACK light. The display indicates the line number of the authenticators TACFIRE expected to receive. Clear the display and turn off the indicator lamps by pressing the X key. This action resynchronizes the AUTH LINE NO field of the status menu. Transmit the message again.
(c) If the destination did not receive the message, no ACK or NAK indications are displayed. The try (retransmission) number is incremented. Transmit the message again.
b. Composing a Message in an Off-Line Compose Message File and Transmission.
(2) Note the mode menu entry FILE MSN=#. Select the off-line compose message file, F3 through F9, in which the message is to be composed by pressing the appropriate numeric key. The file number specified replaces the #.
(3) Note the mode menu entry A=MSG TYPES. Display the message type menu by pressing the A key.
(4) Note the F# ACTIVE entry on the message type menu. The # indicates the off-line compose message file in which the message will be composed. Select the message to be composed, and display its skeleton by pressing the appropriate alphabetic key.
(5) Compose the message as described in subparagraphs a(6), (7), and (8) above.
(6) The message cannot be transmitted from the off-line compose message file. It must be transferred to an active mission buffer. Display the mode menu by pressing the MODE key.
(7) Note the 1=MSN1 ACTV or 2=MSN2 ACTV entry. This indicates the mission buffer into which the message will be transferred. Note the FILE MSN = # entry. Select the off-line file in which the message was composed. The specified file number replaces #.
(8) Note the mode menu entry G=ENABLE FILE MSG. Press the G key to transfer the composed message from the selected off-line file into the active mission buffer.
(9) Transmit the message as described in subparagraph a(9) above.
c. Composing the FR QUICK Message.
(2) Make one of the following entries or selections:
(4) Assign an URGENT or NORMAL priority to this fire request.
d. Composing the FR GRID Message.
(2) Enter the target location grid coordinates (subparagraph v below).
(3) Enter the OT direction (to the nearest 10 mils), or select the GT line.
(4) Enter the target type and description (subparagraph w below).
(5) Select the desired shell-fuze combination to be fired in effect.
(6) Select the desired method of control.
(7) Select a LOW or HIGH angle trajectory.
(8) Assign an URGENT or NORMAL priority to the fire request. Select FPF (ASSIGN ONLY) to establish an FPF or Copperhead priority mission.
e. Composing the FR SHIFT Message.
(2) Enter the number of the known point from which the target location is determined.
(3) Enter the OT direction (to the nearest 10 mils).
(4) Enter the shift information which locates the target with respect to the known point (subparagraph x below).
(5) Enter the target type and description (subparagraph w below).
(6) Select the desired shell-fuze combination to be fired in effect.
(7) Select the desired method of control.
(8) Select a LOW or HIGH angle trajectory.
(9) Assign an URGENT or NORMAL priority to the fire request. Select FPF (ASSIGN ONLY) to establish an FPF or Copperhead priority mission.
f. Composing the FR POLAR Message.
(2) Enter the target location polar data (subparagraph w below).
(3) Enter the target type and description (subparagraph w below).
(4) Select the desired shell-fuze combination to be fired in effect.
(5) Select the desired method of control.
(6) Select a LOW or HIGH angle trajectory.
(7) Assign an URGENT or NORMAL priority to the fire request. Select FPF (ASSIGN ONLY) to establish an FPF or Copperhead priority mission.
g. Composing the FR LASER Message.
(2) Enter the target location laser polar data (subparagraph z below).
(3) Specify the type of laser mission to be conducted.
(b) Select PRED PNT to request an FFE fire mission (at the observer's command) on a position to which the observer expects the target to move.
(c) Select TRAK TGT to request a time on target on a position to which a target is predicted to move. The target must be lased at two locations. The TACFIRE or BCS assumes the target is traveling in a constant direction and at a fixed rate. An engagement point is determined accordingly.
(d) Select DRAW TGT to describe an irregularly shaped target. The target size and shape may be specified by lasing two to eight locations. DRAW TGT must be specified for each point except the final one, when LAST PNT must be selected.
(e) Select TRILAT to determine the observer's location (grid coordinates) by using two known points. The FDC must be told (by FREETEXT message) which known points will be lased and which known point is on the observer's left. The leftmost known point must be lased first and identified as PT NO - 1. The rightmost known point must be lased second and identified as PT NO - 2. The BCS then computes the observer's location.
(f) Select RESECT to determine the observer's location by using one known point. The FDC must be told (by FREETEXT message) which known point will be lased
(4) Enter the target type and description (for fire requests) (subparagraph w below).
(5) Select the desired shell-fuze combination to be fired in effect (for fire requests).
(6) Select the desired method of control (for fire requests).
(7) Select a LOW or HIGH angle trajectory (for fire requests).
(8) Assign an URGENT or NORMAL priority to the fire request. Select FPF (ASSIGN ONLY) to establish an FPF or Copperhead priority mission.
h. Composing the SUBQ ADJ Message.
(2) Enter the OT direction (to the nearest 10 mils), or select the GT line. This may be inserted by the DMD.
(3) If the adjusting round was observed and a shift will be made, select OK. If the adjusting round was not observed, lost, or erratic, select DNO, LOST, or IGN RD, respectively.
(4) Enter the shift information which adjusts the fire onto the target (subparagraph x below).
(5) Enter the fire mission target number. This is extracted from the message to observer and may be inserted into the message by the DMD.
(6) Select the desired shell-fuze combination. Specify NO PREF if no change to the adjusting or FFE munitions is desired.
(7) Select the desired method of control.
(8) Select a LOW or HIGH angle trajectory. It should match the trajectory specified in the fire request.
i. Composing the SA LASER Message.
(2) Enter the burst or target location laser polar data (subparagraph z below).
(3) Specify the status of the adjusting round and which location (burst or target) has been lased as follows:
(5) Select the desired shell-fuze combination. Specify NO PREF if no change to the adjusting or FFE munitions is desired.
(6) Select the desired method of control.
(7) Select a LOW or HIGH angle trajectory. It should match the trajectory specified in the fire request.
j. Composing the PREC REG Message.
(2) Enter the OT direction (to the nearest 10 mils), or select the GT line. This may be inserted by the DMD.
(3) Select the appropriate command as follows:
(5) Enter the fire mission target number. This is extracted from the MTO and may be inserted into the message by the DMD.
(6) Select the fuze to be fired. Specify N/G if no change is desired.
(7) Select the desired method of control.
k. Composing the EOM&SURV Message.
(2) Enter the OT direction (to the nearest 10 mils), or select the GT line. This may be inserted by the DMD.
(3) Enter the desired refinement (shift) information if the target will be recorded as a known point (subparagraph x below).
(4) Enter the target type (subparagraph w below). This has been specified in the fire request and may be inserted into the message by the DMD.
(5) Select the target disposition.
(6) Enter or select the estimated number of casualties.
(7) Enter the fire mission target number. This is extracted from the MTO and may be inserted into the message by the DMD.
(8) Select EOM to end the mission or EOM RAT to end the mission and record the target as a known point.
l. Composing the HB/MPI Message.
(2) Enter the reference direction. This is extracted from the orienting data received from the FDC and may be inserted by the DMD.
(3) Select the observed error in the burst location as follows:
(5) Enter the number of mils the burst location was right or left of the reference direction.
(6) Select YES if you have been designated to measure the vertical angle; otherwise, select NO. This is extracted from the orienting data and may be inserted by the DMD.
(7) If you have been designated to measure the vertical angle, enter the number of mils the burst location was above or below the reference vertical angle; otherwise, select N/G.
(8) Enter the fire mission target number. This is extracted from the MTO or orienting data and may be inserted by the DMD.
(9) If the burst was observed, select OK If the burst was not observed, lost, or erratic, select DNO, LOST, or IGN RD, respectively.
(10) Select HB if observing a high-burst registration or MPI if observing a mean-point-of-impact registration. This is extracted from the orienting data and may be inserted bv the DMD.
m. Composing the RDR REG Message.
(2) Enter the impact location grid coordinates (subparagraph v below).
(3) If the impact was observed, select OK If the impact was not observed, lost, or erratic, select DNO, LOST, or IGN RD, respectively.
(4) Enter the fire mission target number. This is extracted from the MTO or orienting data and may be inserted by the DMD.
n. Composing the FO CMD Message.
(2) Make one of the following selections:
o. Composing the SHELREP Message.
(2) Enter the direction to the location from which the projectiles were fired.
(3) Enter the impact location grid coordinates (subparagraph v below), omitting altitude.
(4) Select the type of projectiles.
(5) Enter the caliber of the projectiles. Select UNK if unknown.
(6) Enter or select the number of rounds that were fired.
(7) Enter the time the incident occurred.
p. Composing the FL TRACE Message.
(2) The FLOT is specified by two or more location entries. Enter an entry number and the frontline grid coordinates (subparagraph v below), omitting altitude.
(3) Enter the entry number for another frontline location, and enter the second frontline location grid coordinates (subparagraph v below), omitting altitude, for the second entry.
(4) If an observer wishes to send more than two frontline grid coordinates, he must use a second FL TRACE message.
q. Composing the OBSR LOC Message.
(2) Enter the observer location grid cocrdinates (subparagraph v below).
r. Composing the ATI GRID Message.
(2) Enter the target location grid coordinates (subparagraph v below).
(3) Enter the target type and description (subparagraph w below).
(4) Make one of the following selections:
s. Composing the FIREPLAN Message.
(2) Enter the names of the FIREPLAN in which this target is to be included.
(3) Enter the target location grid coordinates (subparagraph v below). The coordinates may be omitted (and N/G selected) if the target has been previously recorded (target number must be entered subsequently).
(4) Enter the target type and description (subparagraph w below).
(5) Select CONFIRMD if the target is confirmed or SUSPECTD if the target is suspected.
(6) Select the accuracy to which the target was located.
t. Message to Observer. Messages to observers are not composed on the DMD. They are transmitted from TACFIRE or BCS and received by the DMD.
u. Composing the FREETEXT Message.
(2) Compose the desired message. It must not exceed 37 characters.
v. Entering Location Grid Coordinates.
(3) Enter a four-digit altitude. In the FR GRID and FIREPLAN messages, the last digit is a zero, and the specified altitude is accurate to the nearest 10 meters. It may be necessary to enter a leading zero.
(4) In those regions of the world near grid zone boundaries, two grid coordinate systems may be used. Select STD if the standard (westernmost) grid zone coordinates are used; select EST if the easternmost grid zone coordinates are used. If the location is not near a grid zone boundary, select STD.
w. Entering Target Type and Description.
(2) Enter the number of elements in the target.
(3) For personnel targets, select their degree of protection. For other target types, select N/G.
(4) Select the target radius or length. If N/G is selected, TACFIRE and BCS will assume a circular target with a 100-meter radius.
(5) For rectangular targets, select the target width. For circular targets, select N/G.
(6) For rectangular targets, enter the target attitude.
x. Entering Shift Information.
(2) Select the direction of the desired range shift. The magnitude of the range shift must be entered subsequently. If no range shift is desired, select N/G.
(3) Select the direction of the desired vertical shift. The magnitude of the vertical shift must be entered subsequently. If no vertical shift is desired, select N/G.
y. Entering Target Location Polar Coordinates.
(2) Enter the OT horizontal distance.
(3) Select the direction of the desired vertical shift. The magnitude of the vertical shift must be entered subsequently. If no vertical shift is desired, select N/G.
z. Entering Target Location Laser Polar Coordinates.
(2) Enter the OT slant distance.
(3) Select the direction, and enter the magnitude of the vertical angle.
| NOTE: This information can be transferred across the DMD-G/VLLD interface and entered automatically when the target is lased. Section II. |
|---|
FORWARD ENTRY DEVICE
B-11. OPERATION OF FORWARD ENTRY DEVICE CP-1995/U
a. Description. The forward entry device (FED) is a lightweight, hand-held communications message processor. It can compose, transmit, receive, edit, store, and display messages to conduct fire support. Messages that it transmits and receives include requests for fire, artillery target intelligence messages, messages to observers, plaintext messages, observer locations, registrations, fire plans, and the forward line of own troops (FLOT). The FED performs polar-to-grid conversions, calculates the observer's position location, and interfaces with the G/VLLD to process laser missions. The message processor performs the tasks of message composition, editing, address coding, error control checking, and net protocol. The operator can specify message data rates, addresses of receiving agencies, and keying times. The FED can transfer its software to another FED. The FED can be programmed either to function as a FIST FED or for use by an observer. The FED is shown in Figure B-8.
b. Data Entry and Display. Information is entered into the FED by use of a keyboard consisting of 64 alphanumeric, symbol, and function keys. The display screen can display 25 lines of text with 40 characters per line.
c. Memory Capacity. With the FED, an observer can store nine active messages at one time, including two fire missions. The FED can hold 40 messages in the received buffer and can store 10 messages in the save buffer. The FED also stores copies of the last 25 messages transmitted.
d. Communications. The FED communicates either over radio by use of a CX-8830 cable or over wire. It gives the observer a single-channel digital capability with point-to-point and netted (multiple subscriber) communications.
e. Authentication. Authentication procedures with a FED are similar to those with a DMD. The FED can store up to four authentication code tables of 100 authenticator pairs each as well as an authentication key code.
f. Power Supply. The FED is powered either by an internal battery (BA-5800 lithium battery) or by 28 volts DC using a DCA-11 DC adapter with a CX-8835 cable.
B-12. FORWARD ENTRY DEVICE MESSAGE FORMATS
The FED communicates with other digital devices by using 25 fixed-format message types. These types are divided into the six categories discussed below.
a. Standard Fire Requests. FED-equipped observers use seven standard fire request messages to conduct fire missions.
Figure B-8. FORWARD ENTRY DEVICE
(2) FR GRID (Fire Request, Grid Coordinates). The FR GRID message is used to request fire by using the grid coordinates method of target location.
(3) FR SHIFT (Fire Request, Shift From a Known Point). The FR SHIFT message is used to request fire by using the shift from a known point method of target location.
(4) FR POLAR (Fire Request, Polar Coordinates). The FR POLAR message is used to request fire by using the polar coordinates method of target location.
(5) FR LASER (Fire Request, Laser, Polar Coordinates). The FR LASER message is used to request fire by using the laser polar coordinates method of target location. Interface with the G/VLLD enables data to be transferred directly from the G/VLLD into the FR LASER message.
(6) FR MOV1 (Fire Request, Moving Target, One Point). The FR MOV1 message is used to request fire on a moving target by using one set of grid coordinates.
(7) FR MOV2 (Fire Request, Moving Target, Two Points). The FR MOV2 message is used to request fire on a moving target by using two sets of grid coordinates.
b. Adjustment Messages. The four adjustment messages are used to make necessary corrections for previously requested missions.
(2) SA COORD (Subsequent Adjustment, Grid Coordinates). The SA COORD message is used to adjust fires onto a target when an FR GRID message has been used in the initial request for fire.
(3) SA LASER (Subsequent Adjustment, Laser). The SA LASER message is used to adjust fires onto a target when an FR LASER message has been used in the initial request for fire.
(4) EOM&SURV (End of Mission and Surveillance). The EOM&SURV message permits the observer to end a fire mission, make refinements, report target surveillance, and request that a target be recorded.
c. Registration Messages. The three registration messages are used in observing precision, HB or MPI, and radar registrations.
(2) HB/MPI (High Burst or Mean Point of Impact). The HB/MPI message is used to report spottings made in observing an HB or MPI registration.
(3) RDR REG (Radar Registration). The RDR REG message is used by a radar section to report the impact grid coordinates of rounds fired in a radar registration.
d. Intelligence Messages. The three intelligence messages are used to report information of intelligence value.
(2) ATI POLAR (Artillery Target Intelligence, Polar Coordinates). The ATI POLAR message is used to report enemy locations by use of polar coordinates.
(3) SHELREP (Shelling Report). The SHELREP message is used to report information concerning the impact of enemy artillery or mortar fire.
e. Information Messages. The seven information messages are used to send and receive various important information.
(2) FL TRACE (Frontline Trace). The FL TRACE message is used to report the front line of troops of the observer's associated maneuver element.
(3) FM ALERT (Fire Mission Alert). The FM ALERT message is used to alert the FDC or another subscriber about a fire mission.
(4) FO CMD (Forward Observer Command). The FO CMD message is used to fire a mission established at the observer's command and to order check firing. The FDC uses this message to report SHOT, SPLASH, and READY to the observer.
(5) MTO (Message to Observer). The MTO is used by the FDC to report fire mission data to the observer.
(6) OBSR, OC (Observer Location). The OBSR LOC message is used to report the observer's location to the FIST or FDC. The FDC uses this message to report the observer's location to the observer when that location is determined by resection or trilateration.
(7) FREETEXT (Plaintext). The FREETEXT message is used for nonformatted messages.
f. Remote Loop Test. The remote loop test (LOP TEST) message is used to conduct a test of the communications link between digital subscribers. The loop test interval is established during initialization. Under normal operations, a warning message is received if the loop test fails.
The FIST's FED can be programmed to function in one of three message transfer modes for each observer.
a. Review Mode. All message traffic from an observer's FED is addressed to the FIST's FED. The message must be called up, modified if desired, and then retransmitted to the subscriber selected by the FIST.
b. Automatic Mode. A link is established between two subscribers of the FIST's FED A message addressed to the FIST's FED for another subscriber is automatically readdressed and transmitted to the receiving subscriber. No action by the FIST is necessary when the automatic mode has been programmed for two subscribers.
c. Fire Request Approval Mode. A link is established between an observer and a fire support asset. The initial request for fire is actioned by the FIST as in the review mode. A link is then established, and subsequent messages between the observer and the fire support asset are transmitted as in the automatic mode.
Before use, the FED must be prepared as discussed below.
a. Power Source Installation. Take the following steps to install the power source:
b. Communications Interface.
(2) Wire. Strip one-half inch of insulation from the ends of the wire line, and insert them into the FED binding posts.
c. Operational Checks. Take the following steps to ensure proper operation of the FED:
d. Initialization. The following steps explain how to establish the FED status, net status, subscriber (member) data, and authentication table:
-- TIME SET.
-- LOP TEST.
-- OBSERVER.
-- LOCAL ADDRESS.
-- FED ADDRESS.
-- KEY BELL VOLUME.
-- MSG BELL VOLUME.
-- DISPLAY DELAY.
-- TEST DATA.
-- NORTHING.
-- ALTITUDE.
-- GRID ZONE.
| NOTE: If self-location is to be used, go to subparagraph e below. |
|---|
-- CLOUD HEIGHT.
-- G/VLLD CODE.
-- VISIBILITY CODE.
-- PREAMBLE.
-- RATE.
-- DELAY.
-- CONNECTION.
-- SQUELCH.
-- ROUTING.
-- UNIT.
-- EASTING.
-- NORTHING.
-- ALTITUDE.
-- GRID ZONE.
-- CLOUD HEIGHT.
-- G/VLLD CODE.
-- VISIBILITY CODE.
-- DEVICE TYPE.
-- ROUTING MODE.
-- OBSERVER.
| NOTE: Cloud height, G/VLLD code, and visibility code are laser data for an FO with a laser device. |
|---|
e. Self-Location. Calculate the FED self-location as follows:
(2) Display SURVEY MODE METHODS. The observer uses one of four methods in calculating FED self-location.
B-15. POWER OR COMMUNICATIONS FAILURE
In case of power or communications failure, certain steps must be taken to restore the FED to operation.
| WARNING Before reestablishing power, always turn the POWER switch to OFF. |
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a. Battery Power. The following are steps for restoring battery power:
b. External Power. The following are steps for restoring power from an external source:
c. Communications Failure. The following are steps for restoring communications:
B-16. SAVE OR PURGE DATA AND POWER DOWN
The following paragraphs cover how to save or purge all operational data, how to power down the FED, and how to disconnect the communications and power sources.
a. Save Data. The following are steps to save data:
b. Purge Data. The following are steps 10 purge operational data:
c. Disconnect Power Source. Remove either the BA-5800/U battery or the DCA-11 DC adapter from the FED.
d. Disconnect Communications Equipment. Remove the CX-8830 cable if using a radio. If using wire, remove the wire.
B-17. UP-LOAD AND DOWN-LOAD THE CURRENT FORWARD ENTRY DEVICE SOFTWARE
The following paragraphs provide information on how to connect a host FED to a target FED and how to transfer current software data from the host FED to the target FED.
a. Connect a host FED to a target FED by using a CX-8834 cable.
b. If the target FED has no software, initialize it as follows:
c. If the target FED has software, down-load the host FED current software as follows:
d. Up-load at the target FED as follows:
e. Return the host and target FEDs to mode menu as follows:
f. Complete the up-load and down-load of software as follows:
B-18. MESSAGE PROCESSING PROCEDURES
a. Processing Messages in the Received or Saved Message Queues or the Message Copies File. This paragraph covers procedures on how to display a message from the received or saved message queue and from the message copies file, how to edit and transmit a message from the received or saved message queue, and how to save or delete a message in the received or saved message queue.
| NOTE: Messages from the MESSAGE COPIES file can only be displayed. |
|---|
b. Moving and Copying Messages in the Local Files.
c. Processing Information Messages. Proces information messages as follows:
d. Processing Mission Data in the Mission Data Files. The following are procedures to display mission data from the active mission list or member data summary and to edit or delete a mission data record:
-- Redisplay the ACTIVE MISSION LIST or MEMBER DATA SUMMARY.
e. Processing Local Known Points.
f. Processing Recorded Targets.
B-19. FIRE MISSION PROCESSING PROCEDURES
a. Area Fire Mission Procedures.
b. Precision Registration Mission Procedures. The FDC initiates the precision registration mission by requesting the observer's direction to a target specified by the FDC or selected by the observer.
c. High Burst/Mean-Point-of-lmpact Registration Mission Procedures.
d. Copperhead Mission Procedures.
e. Final Protective Fire (FPF) Mission Procedures. The following procedures detail how to conduct a center point or a laser draw FPF mission.
| NOTE: When conducting a laser draw mission, the automatic target numbering capability must be turned off first. |
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| NOTE: If conducting a laser draw mission, transmit an FR LASER message for each aimpoint requested by the FDC. For the last aimpoint transmitted MISSION is LAST PNT. |
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| NOTE: The preceding procedures for subsequent adjustments are followed until the adjustment phase is completed. |
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| NOTE: To save an FPF in the off-line file for reexecution later, follow the procedures in subparagraph B-18b above. |
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f. Moving Target Mission Procedures.
(b) Display FR MOV1 or FR MOV2 message.
(c) Enter data as required, including PRTY FS in the PRIORITY field.
(d) Transmit FR MOV1 or FR MOV2 message to the FDC. ACK should appear in the status line.
(e) Display MTO received from the FDC.
| NOTE: If the following messages are received, go to the subparagraphs indicated and continue the procedures: FO CMD:UPDTGT.... f(1)(f) Accurate FO CMD:PREDPT--not under check fire.... f(1)(i) Inaccutate FO CMD:PREDPT... f(1)(j) Accurate FO CMD:PREDPT--under check fire.... f(1)(o) |
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(g) Enter updated information as required.
(h) Transmit FR MOV1 or FR MOV2 message. ACK should appear in the status line.
| NOTE: Go to subparagraph f(1)(f) to process the next FO CMD. |
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(j) Form the FO CMD:CHECK FIRE message.
(k) Transmit the FO CMD:CHECK FIRE message. ACK should appear in the status line.
(l) Form the last FR MOV1 or FR MOV2 message.
(m) Enter updated information as required.
(n) Transmit the FR MOV1 or FR MOV2 message. ACK should appear in the status line.
| NOTE: Go to subparagraph f(1)(f) to process the next FO CMD. |
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(p) Display MESSAGE TYPES from the mode menu.
(q) Display the FO CMD message.
(r) Enter data as required, including CANCFR in the MISSION INFO field.
(s) Transmit the FO CMD message. ACK should appear in the status line.
(2) Delete a moving target mission as follows:
g. Immediate Suppression Mission Procedures.
| NOTE: If FR GRID is displayed, go to subparagraph g(1)(d). If LOCAL FILES is displayed with a warning, go to subparagraph g(1)(b). |
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(c) Display the FR GRID message.
(d) Enter data as required, including FFE in the CONTROL field and URGENT in the PRIORITY field.
(e) Transmit the fire request to the FDC. ACK should appear in the status line.
(f) Display the MTO, FO CMD:SHOT, and FO CMD:SPLASH messages in sequence as received.
(2) Process subsequent adjustments as follows:
B-20. CHECK FIRE AND CANCEL CHECK FIRE PROCEDURES
a. Check fire a fire mission as follows:
b. Cancel check fire on a mission as follows:
FIST DIGITAL MESSAGE DEVICE
B-21. OPERATION OF THE FIST DMD (AN/PSG-5)
The FIST DMD (Figure B-9) has three major functions:
a. Use of the FIST DMD reduces the number of TACFIRE computer subscribers. All communicating resources assigned to a FIST normally communicate only with the FIST DMD. All forward observer-TACFIRE communications can be controlled by the FIST DMD. The company FSO decides which information must be forwarded to TACFIRE.
b. Instead of each FO communicating directly with TACFIRE, all FOs assigned to a FIST normally communicate only with the FIST DMD. The company FSO has control in deciding the destination of information from each subscriber. Two obvious benefits from this system are:
The net effect of these changes is to reduce the number of messages handled by TACFIRE, thus improving reaction time of the system.
c. The FIST DMD allows communication among the various communications nets. Thus, an FO on one radio net can communicate, through the FIST DMD, with a subscriber on a different radio net without changing his radio. The only requirement is that both subscribers appear in the net assignment table of the FIST DMD. Figure B-10 shows one possible configuration with the subscribers shown in the FIST DMD net assignment table. With this arrangement, it is possible, with the approval of the company FSO, for DMD A on net 2 to run a mission, with a howitzer platoon BCS (S) on net 1. The FIST DMD provides the communications link between nets 1 and 2.
Figure B-9. FIST DMD
d. Except for the relay function, all traffic is addressed to the FIST DMD (F in Figure B-10). The company FSO decides which subscribers can communicate with each other and under what circumstances this communication will be allowed. For example, if DMD A initiates a fire request, the company FSO may decide that the battalion mortars are the proper choice for the particular target type. The company FSO can route the fire request and all subsequent messages related to that target to the battalion mortars (R). This type of operation is called the fire request approval mode.
e. There are two other modes of operation. Before DMD A started the fire request, the company FSO could have decided that all traffic from DMD A should automatically be routed to another subscriber; for example, the battalion FDC. This is called the automatic mode. The company FSO also could have placed DMD A in the review mode. In this mode, all traffic from a subscriber (for example, DMD A) must be viewed by the company FSO. The company FSO then has the choice of forwarding the unaltered traffic to another subscriber (for example, battalion FDC), changing the text of the traffic and forwarding it to another subscriber, or terminating the message.
f. Thus, some of the decisions that were previously made at the battalion TACFIRE level are now made by the company FSO. The FIST DMD gives the company FSO the means to use and coordinate his local resources, provide the necessary communications links, and reduce the traffic volume at the battalion TACFIRE level.
Figure B-10 TYPICAL NET ASSIGNMENTS
In addition to its other functions, the FIST DMD can be used as an FO DMD. All operations that are possible with an FO DMD are also possible with the FIST DMD. In addition, expanded capabilities are provided. These capabilities, which are unique to the FIST DMD, are explained in the following paragraphs.
a. FIST Location. The FIST location, easting, northing, and altitude, can be entered in the FIST DMD any one of three ways. If the absolute grid location of the FIST is known, it can be manually entered directly into the FIST DMD. The second method involves observation of a single known point in calculating the FIST location. The observation data may be entered manually through the keyboard or automatically from the G/VLLD. The FIST location also can be determined by use of observations to two known points. The calculation necessary to determine the FIST location in grid coordinates is done automatically by pressing one key of the FIST DMD. The location calculated is displayed in the STATUS display of he FIST DMD and is used in converting polar data to grid lata.
b. Polar to Grid Conversion. The FIST DMD operator may convert polar data to grid data. He can convert following message types:
For example, the FIST DMD operator may use his laser range frnder to supply polar data in an FR LASER message he is composing. He may transmit the completed FR LASER message, or he may choose to have the FIST DMD automatically convert it to an FR GRID message before he transmits it.
c. Mission Buffers. The MSN1 and MSN2 buffers are the only two buffers from which messages can be transmitted; only one of these buffers can be active at a time. Unlike the FO DMD, a mission can be initiated in the active mission buffer and then stored in the off-line message files. When done in this manner, the mission data are also stored in the off-line file, and the file is protected against any changes. When a message that was originally composed in a mission buffer is moved from the off-line message files back to the active mission buffer, the current message in he active mission is destroyed. The mission data in the off-line file are also transferred along with the message. Using this feature, it is possible to interrupt a mission and start a new one. When the new mission is completed, the old mission can be resumed without loss of data.
d. Message Files. As with the FO DMD, the message files, F3 through F9, can be used for off-line message composition. A unique feature of these buffers in the FIST DMD is that a mission data file is associated with each buffer.
e. Message Transfer. Just as with an FO DMD, messages also can be composed directly in the off-line message files. However, in this case, a separate mission data buffer is not associated with the composed message. Also, when the message is transferred to the active mission buffer, the current message in the active mission buffer is destroyed and the message that is transferred uses the mission information in the active mission data file. The message that was composed in the off-line message file is not erased from the message file when it is transferred to the active mission buffer. However, active missions that were transferred to the message files are erased from the message files when they are moved back to the active mission buffer.
| EXAMPLE A priority Copperhead mission is stored in buffer F3. There is a mission data file associated with buffer F3 that contains data such as target number, time of flight, and mission number. These data are used in the composition of several diiferent messages when this mission is running. MSN1 buifer is active, and the FIST DMD operator is running a non-Copperhead mission. In the middle of this mission, the Copperhead priority target appears. The FIST DMD operator decides that the target is more important than the mission he is currently running. He files the active mission. This moves the message in the MSN1 buffer and the associated mission data to a message file. Then message file F3 is activated. This moves the message and associated mission data from buffer F3 to the active buffer, MSN1. The proper mission data and message are now in the active mission buffer, MSN1, and the active mission data file. The Copperhead mission can be completed. After completion of the Copperhead mission, the old mission can be resumed by repeating the message or data transfer procedure. |
|---|
f. File Protection. If a message is composed in an active mission buffer and stored in off-line files or is currently in the active mission buffer, it will be protected from changes. If a Copperhead-related message or an FPF message that was originally composed in the active mission buffer is stored in the off-line files, it will be shown in the MESSAGE FILES display with an underlined C for Copperhead or an underlined F for an FPF mission. Other types of missions that were originally started in the active mission buffer and then transferred to the off-line message files are indicated by an underlined A in the MESSAGE FILES display. Any attempt to change any of these stored messages or to file another message in the same file will cause an error message to be displayed. It will state either CANNOT CHANGE FILED ACTIVE MSN or ACTION WOULD DELETE FPF OR COPPERHEAD PRIORITY MESSAGE.
MORTAR BALLISTIC COMPUTER M23
The MBC (Figure B-11) is hand-held, lightweight, and battery-powered. It is used for automated computations, digital communications, and displaying mortar-related information.
The MBC performs the following functions:
The MBC storage contains the following:
B-26. DMD SUPPORTED MISSION PROCESSING
The MBC transmits and receives digital communications from DMDs or FIST DMDs. This capability reduces mission processing time and provides a more secure communications network. The MBC receives and processes digital fire requests (FR) and subsequent adjust (SA) messages. It can transmit ACK, MTO, and shot or splash messages.
Figure B-11. MORTAR BALLISTIC COMPUTER M23
SPECIAL PURPOSE POWER SOURCES
The DMD AN/PSG-2A and the FIST DMD AN/PSG-5 may be operated with 24-volt DC vehicular power. A receptacle cable assembly unique to each device listed herein is available for connection to vehicle receptacles. (The DMD m
