text: Appendix C
  MAINTENANCE OR SYSTEM FAULT
  C-7. Another possible reason to operate degraded is because a piece of automated fire control system
  temporarily goes down for a maintenance related issue. Unit level TTP, battle drills, and SOPs can allow the
  units to reciprocally lay a howitzer, transfer the howitzer or launchers to another FDC, or switch to a backup
  piece of fire control equipment. All in order to maintain fires and TA capability.
  C-8. Unit TTP and SOPs for maintenance related work arounds vary by the type of equipment and the nature
  of the fault. Self-locating howitzers are able to reciprocally lay with another howitzer in order to maintain
  firing capability, while a radar system may have to rely on another system to fill its mission while the fault
  is being repaired.
  THE THREAT TO GLOBAL POSITIONING SYSTEMS
  C-9. One of the greatest threats is a persistent disruption of the GPS affecting positioning, navigation, and
  timing in operations. Timing, especially for secure communications, can be controlled by the net control
  station and pushed to subordinate radios. Units must ensure they load the proper communications security
  (referred to as COMSEC) into their GPS systems to help prevent degradations in the signal quality and
  provide the most accurate data possible.
  C-10. Pre-combat checks and pre-combat inspections should be performed to ensure GPS receivers are
  keyed. A DAGR is keyed through the J1 connector for loading the crypto variable key. DAGRs utilize over-
  the-air distribution for updates once they have been physically keyed. DAGRs should be powered on at least
  once a month to ensure the updated keys are downloaded. Leaders should verify these checks are being
  performed.
  C-11. There are multiple technologies and techniques that can be utilized to improve GPS operations when
  jamming occurs. The best solution is to use anti jamming equipment if available. If anti jamming equipment
  is unavailable, block the signal by placing a barrier (for example, your body) between the device and the
  suspected source of jamming. If using your body, slowly pivot 90 degrees every two minutes until the signal
  is regained. The EMI emitter is then behind you. Alternatively, the receiver can be placed in a hole six inches
  deep. A vehicle hatch may be used as a hole. Allow two minutes for the device to acquire the signal. If neither
  of these techniques resolve the issue; move. The emitter is too close for mitigating techniques to have any
  effect.
  C-12. FA systems can operate in a GPS denied environment. Units must be prepared and trained to execute
  their mission using INS, maps, aiming circles and compass when necessary.
  THE THREAT TO NETWORK CONNECTIVITY
  C-13. Enemy CEMA can disrupt the network affecting key means of communications. Units must ensure
  they have an adequate PACE plan. Ensure it is known and rehearsed at all organizational levels in order to
  maintain communications and firing capability as long as possible.
  C-14. Digital communications are the primary means for transmitting fire commands. If digital
  communication is lost or degraded it must be reestablished as soon as possible. Degraded digital
  communication uses the AFATDS purely as a technical fire direction computer and the FDC personnel would
  transmit the fire command by voice. If one howitzer in the battery or platoon loses digital communications,
  the FDC will issue voice commands to that howitzer or the howitzer can fire data from an adjacent section.
  If two or more howitzers or launchers lose digital communications, the FDC may direct all howitzers or
  launchers to use degraded mode. The howitzers or launchers can then take fire commands by voice only. To
  facilitate voice commands, the FDC provides the fire command standards to the section chief after occupation
  of the position.
  C-15. If digital communication is denied or degraded with the supported element, fire missions, fire plans,
  FSCMs, and any other data can be transmitted by voice. If voice communications are not possible courier or
  liaison personnel can be utilized.