INS Alignment to NAV/IFA

[fl0w]

I only have 2 questions in this instance.

 

Whenever I finish my INS alignment inside of the Harrier on the Tarawa or on land, am I supposed to:

 

1. Move my INS knob to NAV or IFA mode

and 2. What specifically is IFA?

 

Whenever I watch a tutorial or get involved in the mission, I go for NAV mode but whenever I am in a hot start of the Harrier, it is in IFA mode. Any answers are appreciated, and apologies if this has already been answered.

[razo+r]

isn't IFA in flight alignement?

[Ramsay]

am I supposed to:

 

1. Move my INS knob to NAV or IFA mode

IFA is the preferred mode, it constantly updates the the INS with GPS data, correcting any drift (~1 nm/hr not modelled).

2. What specifically is IFA?

IFA = In Flight Alignment.

Nav = INS (Inertial Navigation System), it can be updated by GPS or via TACAN, Overfly waypoint point, etc. (not modelled).

 

IRL, IFA is the preferred navigation mode but NAV is used every 5th flight* or in areas where the GPS signal is degraded/weak.

 

*to ensure the INS doesn't have a error masked by GPS/IFA updates

Edited May 29, 2019 by Ramsay
Typo

[fl0w]

Any idea as to why the hot start throws you to IFA then? And is there a point to having a preference over one or the other? (Assuming IFA is only modeled for just aligning in the air at this stage)

[Ramsay]

Any idea as to why the hot start throws you to IFA then?

IFA is not just an alignment mode in the Harrier.

 

IFA is the preferred navigation mode as it couples the GPS to INS and is the mode a pilot would use IRL.

 

NAV mode with realistic INS alignment, drift, position fixes, etc. is the mode that is not modelled (selecting NAV, you get a INS that is still linked to the GPS and shows no position error).

Edited May 29, 2019 by Ramsay

[Harlikwin]

Any idea as to why the hot start throws you to IFA then? And is there a point to having a preference over one or the other? (Assuming IFA is only modeled for just aligning in the air at this stage)

 

The hot start "ends" there because thats typically the most accurate. IFA GPS coupled nav mode that gives you an overall precision of ~10-20m or less depending how you count precision (x,y or X,Y,Z where the errors are larger). For DCS purposes there is no error modeled for the harrier at the moment. IRL the main reason to take it out of IFA is if the OPFOR has the ability to jam/degrade/spoof the GPS altogether, which most nations do at this point. So the INS is just as relevant now as it ever was, unless you are dropping bombs on mud huts.

 

The other reason INS is so important is most of your weapon systems need that info for proper targeting.