Could somebody please explain INS mode??

Could somebody please explain what it means when INS appears in the top left of the screen when using DMT/FLIR or when the IRMAV is uncaged?

Target Point is tracked through INS not optical (TV).

Thanks but that doesn't really advance my knowledge. Do that mean in INS the TV is slaved to a designated target point. How about when IRMAVs are uncaged? When IRMAVs are uncaged and TPOD is on they follow where the TPOD is looking despite being in either IRMV or INS mode so what is the difference. Can you fire IRMAVs in INS mode and if so where will they hit?

I'm not totally sure of how to use INS for targeting. I believe you basically point your VV (Velocity Vector) at the target and press TDC-Down. This should put the diamond marker in the HUD on the ground where the VV is at that point, where it should stay, but this is very inexact.

First go to left MPCD and select STRS, then at the top select IRMV. If the IRMV's have not initialized (3 minute cool-down period) already, above OSB 20 you will find STBY over TONE. When STBY changes to RDY, the IRMV's are initialized.

Press SSS-FWD (Sensor Select Switch) to select INS. Switch Master Arm to on (up).

Switch master mode to A/G (Air-to-Ground).

TDC-Down on target.

Press Uncage - the IRMV's IR camera will display in the left MPCD.

Pess SSS-FWD to slave the TDC to the selected IRMV. Use TDC-Left -Right -Forward -Aft to position the IRMV's cross hairs exactly on target. When acquired, they will close nearly completely together over the target. Now just rifle with the Bomb Pickle.

You can immediately uncage the next IRMV and repeat above from uncage, although you will be hard pressed to be able to get on a second target without a lot of practice.

I would highly suggest learning to use the TPOD and/or DTM first though. At least I find them far more useful, and I'm not even sure if INS targeting actually works correctly.

Also, get Chuck's Guide for the Harrier from here: Chuck's DCS Tutorial Library

This relates to the way the Sensors Point of Interest is tracked :

- IRMV → the Maverick IR camera is slewed by the TDC and the Maverick computer tries to keep the image fixed by tracking the contrast differences in the picture

- TV → the DMT camera is slewed by the TDC and the plane computer tries to keep the image fixed optically

- INS → the DMT camera is slewed by the TDC and the plane computer tries to keep the image fixed by pointing the camera at coordinates using the inertial navigation system (INS)

When the DMT cannot see the target (e.g. it goes out of its gimbal limits) the system switches to INS automatically so it can remember where the target was.

As soon as the remembered target comes back in a position visible by the DMT camera, it switche back to TV automatically.

Hope this helps.

Could somebody please explain what it means when INS appears in the top left of the screen when using DMT/FLIR or when the IRMAV is uncaged?

from the A1-AV8BB-TAC-000

Concept. ARBS is a bombing system

which utilizes rate of change of the Line of Sight

(LOS) Angle between the aircraft and target to

compute slant range. When this value has been

computed, the system will provide for and automatic weapons release to impact the designated

target. This is accomplished through the MC

which processes the LOS information along with

air data and attitude information from other

aircraft sensors to compute this target range.

This data in conjunction with ballistics data

results in computed weapon release points. An

angular rate of change of the sight line to the

target, (line of sight rate) referenced to the

velocity vector, is required for ARBS deliveries.

The pilot can utilize either the ARBS DMT or

the INS for designation and tracking of surface

targets. The DMT provides both TV and LST

sensors to provide LOS angles and angle rates to

the MC for computation of target range, height

and weapon release solution. The INS mode uses

either coordinate position or HUD symbol LOS

angles, inertial velocities and either barometric

or radar altitudes via the MC to determine the

release solution.

 

The velocity is further refined using inputs

from AOA and INS pitch and roll angles to

give the direction of the vector.

3. G. The INS sends a signal of the direction

and magnitude of the g-force.

4. Groundspeed. During INS computations

for navigation purposes, a signal of groundspeed is produced.

 

At dive angles less than 20°, the INS

supplies range wind and therefore does not

take target motion into account. In this case,

the along track movement of the target will

slightly affect the elevation sight line spin rate

which, fortuitously, will account for target

motion by approximately 50 percent.

There several docen pages on the manual about INS relations to the ARBS and weapons delivery.

Dual Mode Tracker is a component/subsystem of Angle Rate Bombing System. DMT and ARBS are not part of LiteningII TPOD, or vice versa. TPOD and ARBS can be used together. But each is a separate system. ARBS is old technology, with development traced back to 1957.

DMT has two basic modes. LST and TV.

Laser Spot Tracker (LST), which is a passive sensor that scans for laser reflections from designated target , at preset Pulse Repetition Frequency (PRF) Code. You do not need TPOD to use LST mode, if another element lases the target. If you are carrying TPOD, it can be the laser designator for LST. If you are carrying TPOD and plan on using laser guided munitions, you should put DMT into NITE mode or turn it off. When LST finds the laser spot, ARBS crunches complex math, of measuring slant distance based from relative motion and position of aircraft relative to the laser spot. ARBS then uses slant distance and aircraft position to calculate target position, and provide range and shoot que to pilot.

DMT TV mode, usable in daytime, calculates target position, range , and shoot que, as with LST. But instead of laser, ARBS uses TDC caret and aircraft's navigation system to optically lock on to desired target point. ARBS takes that information and aircraft position data from Inertial Navigation System (INS) to derive slant distance to target, and present range and shoot que. TV tracking works best when there is sufficient daylight for DMT to see the TDC caret. DMT tends to lock on high contrast points in the DMT TV image.

If the above is a bit confusing, blame only me. Concise explanation is that both LST and TV modes of ARBS are used to calculate target position, range , and shoot ques.

LST can be used night and day and TV during the day only. ARBS in LST mode is not a laser, it cannot designate. LST requires a laser spot, from TPOD (when carried), or laser spot provided by another friendly element.

ARBS TV mode uses aircraft's navigation system, its INS, to derive slant range, target position, and shoot que.

Because ARBS uses INS NAV , the INS must be accurate. Which is why you have to wait a few minutes , during preflight and startup, for INS quality to be .7. Without functional and aligned INS NAV, accuracy of weapon delivery is degraded. If INS is allowed to drift, accuracy is degraded to the degree of INS drift. In Flight Alignment navigation option, corrects the drift. LST is more accurate then TV mode.

During flight, check INS accuracy by overflying a terrain feature, and compare to shown position on digital moving map display. If IFA is needed. Have aircraft fly straight and level at constant altitude and indicated speed, and set NAV system to IFA. Wait at least one minute, place navigation into NAV mode, and continue the mission.

I've seen conflicting info about of the INS should be set to NAV or LFA during normal flight operations.

I've seen conflicting info about of the INS should be set to NAV or LFA during normal flight operations.

The preferred navigation method is IFA (tightly-coupled to GPS), however every 5th flight should use NAV mode to confirm the loose coupled INS (degraded fallback mode) is still functioning correctly and errors are not being masked by GPS updates.