What is the field of view for the Unity Window?
6 degrees vertical and 18 degrees horizontal increasing to 30 degrees depending on head movement
When is a round most affected by crosswind and why?
Primarily within the first 3 meters from the end of the gun tube when the forward portion of the projectile leaves the blast envelope and is subject to external wind forces, and the base of the projectile is still protected inside the envelope
What is Cant?
It occurs when the tank is on uneven ground and one gun trunion is higher than the other
What is the Cant Unit?
A simple, rugged, pendulous device mounted on the turret ceiling forward of the CWS
The MRS is used to correct for boresight loss caused by what 2 factors?
Thermal Bending and Gun Tube Droop (Gravitational Bending)
Effective use of the ELRF may be lost to what causes?
1) Internal LRF Failure 2) Vehicle Failure 3) Environmental conditions 4) Man-made or battlefield obscurants 5) Multiple returns from a target small than the LRF beam width with obstructions to the front and rear of the target
What does the reticle pass through and then reflect off to superimpose in the GPS FOV?
The Dicroic Beam Splitter
What is first and last return?
First Return: The first return from 200 tp 7990 meters Last Return: The last return recieved from 7990 meters to 200 meters
When does the symbology display flashing "OOOO"'s?
1) When all returns are less than 200 meters 2) When all returns are 8,000 meters or greater 3) When insufficient light is returned to the reciever to calculate a range
What are the standard battlesight ranges for Sabot, HEAT and Coax?
Sabot: 1200 meters HEAT: 900 meters Coax: 500 meters
When should air temperature and barometric pressure be updated?
Air Temperature: When the air temp deviates by more than 10 degrees Fahrenheit from indexed value Barometric Pressure: When the Baro deviates by more than 1 inch of mercury from indexed value
How long does it take for Ammo propellant to reach the same temperature as the compartment?
Describe the effects of temperature on ammunition propellant in regards to striking targets.
Muzzle velocity increases if ammunition propellant temperature increases, causing the projectile to travel faster and strike higher on the target. The opposite is true for lower propellant temperatures.
What is the purpose of the Balistic Computer Subsystem?
Consistantly calculates and provides signals to control the angle between the GPS reticle, CITV reticle and the main gun
What does the Ballistic Computer Subsystem angle consist of?
1) Ballistic Solutions 2) Lead Angle 3) Parallax Correction
Describe the ELRF.
An Erbium glass laser transmitter with a range reciever using an InGaAs semi-conductor.
Why are APFSDS-T and APDS-T not significantly affected by crosswind?
Because they have a faster flight time
What are the 3 ways for the FCS to display and implement a range other than 150 for CAN?
Gunner lases: 1) If the return is 200 to 1100 meters, this range will be displayed and the ballistic solution for it will be implemented. 2) If the return is greater than 1100 meters, this range will flash twice; the FCS will then desplay and implement a 150 meter solution. 3) If the return is less than 200 meters, "0000" will flash twice; the FCS will then display and implement a 150 meter solution
What are the 8 functions of the IFCEU?
1) Performs calibration functions 2) Provides Gun/Turret control and stabilization signals 3) Provides GPS line of sight control and stabilization signals 4) Performs gun firing inhibits 5) Performs fire control system diagnostics/continuous fault detection 6) Provides CITV line of sight control 7) Provides firing signals for main gun, coax and smoke grenades 8) Converts all analog fire control inputs to digital and forwards them to the ITMPU
What is the purpose of the IFCEU?
To interface with various components in the fire control system and send information to the ITMPU for ballistic solution calculation
What are the gun firing inhibits?
1) Gun/sight error greater than .27 mils in elevation, azimuth or both in emergency mode or normal mode 2) If either normal or emergency mode drift menus are selected 3) In normal mode while conducting the fire control system test or when MRS functions are selected. 4) In emergency mode when the Boresight or Zero functions are selected 5) With coax during target designate operations until the CITV LOS and Coax LOS are within .27 mills in AZ and EL
What actions by-pass all gun firing inhibits?
When the firing trigger on the elevation hand pump is used or the manual blasting machine
What does the ITMPU do?
It is the controller for the data bus, the monitor for the utility bus, it stores critical data in non-volatile memory and calculates the ballistic solution offsets
What does the IHMPU do?
It stores the same critical data for the fire control system as the ITMPU. If the ITMPU is unable to process the ballistic solution, the IHMPU will serve as a backup
The IGCDP contains all the controls and displays required to do what?
1) Provide manual inputs to the computer 2) Bypass automatic inputs 3) Recall stored information 4) Perform maintenance functions
What are the set (nominal) values?
Ammo Temp: 69.8 degrees F Air Temp: 59 degrees F Baro: 29.92 inches of murcury (inHG)
When using the 4-way toggle switch on the IGCDP, what is the movement command actually being applied to?
The Dual Axis Head Assembly (DAHA) for movement in azimuth and elevation
What is the purpose of the ICDU?
It provides the soldier machine interface between the tank commander and the M1A2-SEP vehicle
What are the 3 modes of operation the vehicle can be placed in from the ICDU?
1) VEH SYS (Vehicle system mode) 2) C3 3) DIAG (Diagnostic mode)
Describe the 4 different color groups of buttons on the ICDU.
Blue: CITV Operations Green: Power Control Black: Vehicle Mode Operations and alpha-numeric input Red: for triggers and smoke grenade firing
What does flashing numbers mean in the GPS symbology?
Correct range but incorrect ballistic solution
What are the 4 occasions when the GPS symbology will display flashing "0000"'s?
1) When all returns are less than 200 meters 2) When all returns are 8,000 meters or greater 3) When insufficient light is returned to the reciever to calculate a range 4) When laser range switch is set to safe and the lase button on the power control handles is pressed
What is the purpose of the MRS?
It enables the crew to establish a referrence point during boresighting, then check and correct any change in the relationship between the GPS reticle and the main gun
What is the purpose of the H/TPS?
It is an electro/optical device that monitors hull to turret position and rotation.
What is the purpose of the POS/NAV sensor?
It provides data for calculation of tank position and heading and input of the hull pitch and roll angles for dynamic cant calculations
What conditions must be met for the IFCEU to accept the signal from the Cant sensor?
1) Two identical consecutive values are recieved by the IFCEU 2) The tank is stationary
What is the purpose of the Line Of Sight (LOS) Subsystem?
To maintain the relationship between the GPS reticle, CITV reticle and the main gun
What is the purpose of the DAHA (Dual Axis Head Assembly?
To provide for line of sight stabilization of the scene and reticle in elevation and azimuth
What is the head mirror?
A one piece, highly polished beryllium mirror surface large enough to reflect day, night, unity and laser light
What is the purpose of a resolver?
To sense and report the position in AZ and EL and send that position signal to the IFCEU
What is the purpose of the dual axis gyro?
To provide signals to stabilize the head mirror in AZ and EL
What was the CITV designed for?
For hunter/killer operations and to allow the tank commander to designate targets for the gunner
What is the purpose of the CITV-SM?
It recieves signals from the FLIR scene and produces the video signal for display on the ICDU
What conditions must be met in order for the Tank Commander to lase using the CCHA?
The CITV must be in GUN LOS mode and one of the narrow fields of view (13x, 25x or 50x) must be selected
What conditions must be met in order for the Tank Commander to use the stadia reticle?
The CITV must NOT be in GUN LOS and one of the narrow fields of view (13x, 25x or 50x) must be selected
What is the purpose of PLUMB and SYNCH?
To ensure that the GPS, main gun and the CITV maintain alignment through all angles of elevation
Within how many degrees between the gun and the CITV GLOS does the 16x resolver take over?
Within 11.25 degrees
Why does the 16x resolver take over for the CITV GLOS and gun positioning?
To make more accurate and refined movements
What is the preferred optical system for searching and aquisition of targets both during the day and night?
What is the purpose of the Gun/Turret Drive and Stabilization Subsystem?
It provides control of the main gun and coax machine gun in the stabilized (normal), non-stabilized (emergency) and manual modes of operation
What is the purpose of the Gun Azimuth Gyro?
To work with the Hull Gyro in refining the Hull Gyro correction to stabilize the turret in AZ.
What is the purpose of an LTDV?
To transform the handle (mechanical) movement into an electrical signal
What is the capacity of the Hydraulic Susytem?
20 gallons of FRH, 19 gallons in the resevoir and 1 gallon in the lines
How much fluid is the main hydraulic pump capable of displacing?
Variable fluid displacement from 26 gallons up to 47 gallons per minute
Why is the TIS aiming box a box and not an aiming circle?
Because the TIS is digital therefor incapable of displaying a circle