INS aligment
-
The system is aligned via the lat/long coordinates entered by the operator.
Or taken directly from GPS device (if GPS is good and pilot is validating this position)
-
Or taken directly from GPS device (if GPS is good and pilot is validating this position)
All is correct but one note to remember, INS alignment uses manual or GPS latitude entry only for alignment. Longitude is a comparison of the manual or GPS longitude coordinates entry with last know Longitude stored in the memory.
-
All is correct but one note to remember, INS alignment uses manual or GPS latitude entry only for alignment. Longitude is a comparison of the manual or GPS longitude coordinates entry with last know Longitude stored in the memory.
100%
-
It is possible for an INS to discover its latitude on its own. I know this to be true. The motion around the Earth’s axis is unique for every latitude (N S pair). Heading and local vertical are self-discovered during attitude alignment. The combination of accelerations suggest a loop path the vehicle takes around the Earth. With knowledge of the craft’s azimuth and local vertical it can be combined with the path the craft is taking around the Earth’s axis to find latitude uniquely.
I would guess that the F-16 does not derive latitude for navigation purposes but does check the calculated against the entered as large discrepancies will prove to be unusable in flight.
-
Stubbies is right. There is no compass entry for INS/IRS alignment.
INS/IRS is giving a true heading.
Mag heading is given by software computation based on location, true heading and known Mag variation table.I was thinking it’s like “witch came first the chicken or the egg?”
If you takeoff without allignment there is no heading tape?
Does INS heading drift? Note that when heading NW, in a roll the INS heading will be handed off to all three gyros.
Mag heading must be in an ICP page because I didn’t see a switch for it. -
Mag heading is given by software computation based on location, true heading and known Mag variation table.
.My 1984 D1 says the HSI compass card is the “INS magnetic heading”. I didn’t find that it was computed from True North. And the HSI compass card is INS servo driven just like the ADI.
-
You can only base very little when comparing BMS with 1984 F-16. The only similarities is that it is still an F-16 and…. yeah all the system are different. Engine, avionics, hell even the structure is different.
This one is better but still only a reference, nothing more and not 100% -
page 1-163
The face of the HSI is a compass card driven by the INS so that aircraft magnetic heading is always read at the upper
lubber line.I do not understands much (certainly not this), but I do not think this says anything about INS using magnetic heading, I will keep looking.
-
Anyone got a 1F-16()-2-34GS-00-1?
PS
Not the same as a -34 {1F-16()-34-1-1} -
For the OP, sorry do not mean to continue derailing your thread, I do believe that is you want to fly the JA-37, just performing an 90 alignment should be sufficient in BMS
-
Some EGI info
EMBEDDED GPS/INS NAVIGATION SYSTEM (EGI).
-Description. The EGI system utilizes GPS, and INS to keep an estimate of aircraft position, velocity, heading, attitude,
and altitude. This estimate is referred to as the system navigation solution. To integrate the information from these two sources
and determine the system navigation solution, the system uses a Kalman filter. The Kalman filter mathematically combines the
information from these sensors to produce a more accurate aircraft position estimate than could be expected from the sensors
alone. To insure accuracy of the navigation solution, the system utilizes INS performance model information along with GPS
data to determine the drifting behavior of the INS. In this manner, the system can continue to be accurate even with the loss of
GPS information. EGI includes the following features:
EGI Blended NAV Solution
24-Channel SAASM (Selective Availability Anti-Spoofing Module) GPS Receiver
Direct-Y GPS Acquisition
Fiber Optic Gyro (FOG) INU
DTE Load of EGI GPS Keys and Almanac Data
Automatic Entry of Align Coordinates
EGI Auto IFA
Alignment Refinement Capability
Navigation Database (5,000 steerpoints)
Emergency Airfields.- The EGI system supplies three distinctive navigation solution; INS-Only free inertial solution, GPS-Only solution and
a GPS/INS blended solution. EGI navigation solutions are available upon completion of a ground gyrocompass (GC) alignment
(NORM or STOR HDNG), an automatic or manual in flight alignment (IFA) or when the EGI is in the NAV mode by either
placing the function knob is in the NAV position or auto naving by moving the aircraft with the EGI function knob in NORM. - After each flight is completed, the LN-260 observes and computes a percentage of errors at shut down and stores it in
non-volatile memory. The next time the EGI is turned on, corrections are made to the free inertial solution before NAV is
selected or 80 knots. Errors from Gyro Bias, Gyro Scale Factor, Accel Bias, and Accel Scale Factor are not allowed to build on
subsequent flights.
- The EGI system supplies three distinctive navigation solution; INS-Only free inertial solution, GPS-Only solution and
-
Or taken directly from GPS device (if GPS is good and pilot is validating this position)
Nope you must enter the coordinates for each normal/gyrocompass alignment even if they are correct for SINS/RLG INS systems. The combined INS/GPS units might be different but what is simulated in BMS would require entry.
-
You believe there is way to senses the earth’s rotation while in flight.
You believe the only compass in the a/c is the backup compass. BTW, I know backup compass is not intergraded into any system in the a/c. use a little intuition.
You don’t believe there is algorithm in the INS software that correct for the “known” spinning of the earth spinning under the a/c.
You believe that the clock in the INS is perfect.
You believe that accelerometers are perfect.
You believe that light ring rate gyros are perfect.
You believe that Analog to Digital converters are perfect.
ok, enuff said……Not sure what you are smoking as I’ve never said anything in what you have just tried to pin to me.
-
If you takeoff without allignment there is no heading tape?
No If you take off without INS/GPS going you won’t have a heading tape as that is derived from the INS system.
Does INS heading drift?
ALL INS systems drift thanks to living on a rotating roundish globe. The longer the INS is run or the aircraft is moved the bigger the errors. GPS keeps it in check now a days.
Note that when heading NW, in a roll the INS heading will be handed off to all three gyros.
Which is why both SINS and RLG INS systems attempt to compensate for not travelling across a flat planet that doesn’t spin. They aren’t perfect hence drift is induced.
Mag heading must be in an ICP page because I didn’t see a switch for it.
If you dug around enough you would find the appropriate page on the DED.
-
I would guess that the F-16 does not derive latitude for navigation purposes but does check the calculated against the entered as large discrepancies will prove to be unusable in flight.
The system doesn’t have any error checking for what is entered for lat/longs. If you enter something grossly off the system cannot align and would be completely unusable.
-
My 1984 D1 says the HSI compass card is the “INS magnetic heading”. I didn’t find that it was computed from True North. And the HSI compass card is INS servo driven just like the ADI.
The HSI displayed magnetic north but once again the HSI gets all of it’s information from the INS system when in NAV mode. If what the INS system sensed on alignment was true heading and as is agreed that the HSI is displaying magnetic heading how else do you think that was done?
Mag heading is given by software computation based on location, true heading and known Mag variation table.
The statement above is correct.
-
page 1-163
I do not understands much (certainly not this), but I do not think this says anything about INS using magnetic heading, I will keep looking.
Caper is correct in that the compass card is displaying magnetic heading.
-
@Gas Now there is a gyrocompass. That was my missing link. There had to be a compass some where. And would ya know that the FOG suite is used to allign it.
-
@Gas Now there is a gyrocompass. That was my missing link. There had to be a compass some where. And would ya know that the FOG suite is used to allign it.
There is NO COMPASS used to align any version of the INS system. Just accept it already. I’ve used the term gyrocompass alignment more than a few times and that doesn’t mean there is a compass used to align the system. Good God.
-
There is NO COMPASS used to align any version of the INS system. Just accept it already. I’ve used the term gyrocompass alignment more than a few times and that doesn’t mean there is a compass used to align the system. Good God.
That’s not what I said. I just the FOGs are used to align the gyrocompass.
If the gyrocompass was used to initialize INS after alignment, you wouldn’t find in your end-user docs away.
BTW we did design an INS without FOGs and gyrocompass. It use a fluxgate compass and rate gyros. It also feed data to the FLCS. We were not the first.