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[FUTURE IMPLEMENTATION] Laser scan footprint is not slewable as should.


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Reference: A1-AV8BB-TAC-000 (pg 1-200-202)





  • Can not activate ARBS/LST if ARBS/TV is used to designated a target. Impossible even by first switching INS mode (SSS Up) and then try switch ARBS/LST to scan laser spot in the INS TD area.
  • The ARBS/LST scan pattern should be Roll Stabilized (instead it acts now like A-A mode) so rolling to left/right should keep scan moving by horizon level and not aircraft level.
  • The ARBS/LST should show a scan pattern footprint in the DDI where it can be slewed.
  • The HUD scan pattern can not be selected from ARBS/LST by pressing UNDESIGNATE when ARBS/LST is not locked on laser spot.
  • Currently the ARBS/LST will lock on the TD and stay locked to it. It should perform a Narrow scan pattern in that position. If no laser is spotted, then ARBS/LST should continue scanning in the beam of that TD.
  • The ARBS/LST should not automatically switch to ARBS/TV when laser spot is locked. The pilot needs to press SSS Aft to transfer to TV, this in case if the laser is forced to shut down, otherwise ARBS/LST mode stays on and shows where the laser spot is from the nose.
  • The system shouldn't automatically generate TD. The ARBS/LST mode is required to have enough time and rate to calculate the slant range to target to generate attack solution - after that the INS mode can be selected (SSS Up) to generate a TD for re-attacking.
  • Currently when performing re-attack, the ARBS/TV is automatically slewed to laser spot and ARBS/LST can not be selected. The pilot should revert back to ARBS/LST (disabled after TD going out of gimbal limit) that restart Narrow Scan Pattern in the TD beam. Once it again finds it, pilot can decide what to do.





The ARBS/LST mode can scan in three modes, two of them at 20 deg/s speed:


  • Wide 68° and 20 deg/s.
  • Narrow 24° and 20 deg/s.
  • HUD 8x8°


The Wide and Narrow scan patterns are selected from the DDI and can be slewed inside the DMT gimbal limits (+15/-70° in elevation, +/- 35° in azimuth (and roll stabilization +/-450°)) and are roll stabilized in A-G mode (not in A-A mode).


The scan patterns are possible be slewed (required even to find target), but by default system it will point the scan pattern automatically in angle that is 5 nmi ahead of the aircraft (in the gimbal limits) if no Target Designation (TD) exist. If TD exists, then scan pattern center is moved to it (if target elevation is known, otherwise it is at sea level altitude). So pilot can fly at various altitudes and scan pattern is moved up/down automatically to scan 5 nmi front of the aircraft. The scan pattern is as well roll stabilized, so it will scan the pattern relative to the horizon and not by the aircraft roll angle.


The TDC can be used to move the Wide or Narrow scan pattern. As the Wide mode is as wide as the gimbal limit is, you can only move it up/down and see it position in the DDI as well HUD. The Narrow mode can be slewed to sides as well up/down in the gimbal limits.


 The HUD scan pattern can not be slewed. It is fixed and should scan in a "bow tie" pattern inside the HUD centroid and complete one pattern in 4 seconds. This is the "Snapshot" mode for quick moments by pointing aircraft at the area. To initialize this, the pilot can press SSS Aft -> Undesignate and ARBS/LST performs search. There is no need to press "HUD" in the DDI for this.


In TDC ACTION mode (TDC Down) the ARBS/LST scan mode is stopped and video crosshair is shown on the DDI that can be slewed and when releasing TDC ACTION the crosshair position is used as INS DESIGNATION, after that ARBS/LST scan is resumed by automatically changing scan pattern to Narrow and centered to that Target Designation.


If pilot wants to store the laser spot position as TD, it is required to use SSS Up to switch mode to INS or Aft to get ARBS/TV on the area. That is not automatic. To generate the INS TD from the locked laser spot, the pilot needs to perform proper maneuvers and give enough time for ARBS to calculate the slant range before pressing SSS Up.

Pilot switching to ARBS/TV (SSS Aft) does not generate TD automatically, it requires a contrast lock on the target and if such is acquired, then some time and maneuvers are required by pilot to generate the attack solution. The ARBS/TV functions are required here (no ground stabilization by default, no TD in INS if not commanded).


If the pilot turns the aircraft so ARBS/LST designation center (locked on laser, or INS TD) exceeds the DMT gimbal limits then ARBS/LST mode is automatically turned off and INS mode is activated. The ARBS/LST stops scanning and requires to be initiated again with SSS Aft. This prevents accidental re-designation when outside of gimbal limits while re-attacking.


When the gimbal limits are exceeded, the ARBS/LST view in DDI is swapped automatically to compass rose (EHSD) that aids pilot in re-attack, and in the HUD the LST symbol is replaced by the TD diamond and re-attack steering guidance is shown (the arrow on VV, compass has line, target range etc).


i7-8700k, 32GB 2666Mhz DDR4, 2x 2080S SLI 8GB, Oculus Rift S.

i7-8700k, 16GB 2666Mhz DDR4, 1080Ti 11GB, 27" 4K, 65" HDR 4K.

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  • RAZBAM_ELMO changed the title to [FUTURE IMPLEMENTATION] Laser scan footprint is not slewable as should.

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