Computer history LEOK:
The Mech Lua Trainer (MLT)

The 35 mm AA Tank CAESAR: Introduction

The Caesar system was developed on the basis of Netherlands military requirements for an armoured vehicle equipped with a proven AA weapon coupled to a highly effective radar fire control system and capable of keeping pace with other armoured units on the battlefield.
Oerlikon-Contraves, Hollandse Signaalapparaten and Kraus Maffei' jointly developed the CA-1 weapon system.

The AA tank fills the gap in the defence against low-flying aircraft. The weapon system, mounted on a Leopard 1 battle tank chassis, is fully autonomous, its main components being:

• a search and tracking radar,
• two periscopes,
• fire control system with an analogue computer, and
• a 35 mm twin gun.

The AA tank has a crew of three men: the commander, the gunner and the driver.

• The commander is in charge of the tactical use of the weapon system. He evaluates the air threat, decides about target engagement, and maintains radio communication.
• The gunner is charged with the engagement of the target selected, using the optimum mode of operation. If necessary, a single operator can execute an engagement and operates the entire weapon system.
• The driver manoeuvres the AA tank as ordered by the commander.

The search radar continuously scans the surrounding airspace, no matter whether the vehicle is at standstill or on the move. In the MTI mode of operation, only moving targets are displayed on the radar screen. Each target displayed is automatically interrogated for its identity (friend or foe).

The commander selects the target to be engaged by marking the echo, and presses a button for automatic acquisition and tracking of the target by the tracking radar, whilst air surveillance by the search radar will continue without interruption.

Commander and gunner have a periscope at their disposal. These are used in the optical mode of ground and air target acquisition and tracking, and combat zone observation.

The fire control system aims the guns, taking into account the continuously measured target data, the meteorological data, and the muzzle velocity. As soon as the target is within the effective range, the operator receives the "Ready for Firing" indication.

Training - An Integral Part

The design and realisation of this unique training system took place under technical system responsibility of LEOK-TNO (the electronics laboratory of the national defence research organisation - TNO) and was a joint effort of LEOK, Signaal and the AA-Defence School. The two trainers (MLT-1 and MLT-2) for the RNLA are due for delivery in 1980.

Training Program

• Classroom lectures,
• MLT training sessions,
• Practical exercises with an AA tank.

Classroom lectures for the operators cover all the preparatory aspects of the training in the MLT.
The trainees are first familiarised with the functions and performance of the AA tank and with the safety regulations. Subsequent lessons deal with the theoretical backgrounds of combat situations and the associated reactions. The classroom lectures are integrated with the MLT training sessions, which are adapted to the level of experience of the trainees.

During combat training, operation of the
fire control system is one of the major
elements. This necessitates correlated
periscope/radar pictures in the MLT, as shown.

MLT radar picture without MTI

MLT radar picture with MTI

The MLT permits the execution of combat procedures without spending live ammunition and, additionally, all the procedures necessary to operate the AA tank equipment. From the very start, the operators are in a realistic environment, in which practically any tactical situation can be simulated. Operators, both skilled and unskilled, will improve their acquaintance with the system through the MLT.

The teaching matter is divided into four levels, covering some 50 MLT training sessions of one hour.

• Level 1
  At this level the training sessions consist in practising the operation of the various controls of the weapon system.
• Level 2
  The operator training at level 2 comprises the actions to be taken on the appearance of a target. Experience must be gained in all the actions necessary for the acquisition and tracking of the target by radar and by optical means until fire is opened.
• Level 3
  In this phase of the training, the trainees have to react on their own initiative to the various targets. Hampering factors are now introduced. These factors can be:
  • simultaneous action of several targets,
  • terrain conditions (influencing radar and optics),
  • electronic countermeasures (ECM),
  • simulated equipment failures,
  • high level of background noise (also in the intercom),
  • higher ambient temperature in the turret.
• Level 4
  This is the highest level. The teams are trained in platoons. All operators receive the same exercises in tactical procedures.

The Training System

• Weapon System Simulator
  The three independent training turrets are, internally, exact replicas of the real turret. All the controls and the displays necessary for the tactical training are available, including the periscopes.
  Besides the simulation of the direct physical environment, the weapon system performance and reaction are simulated by computer software and special-purpose simulation hardware. The training in the MLT is thus 'with all hatches closed down', giving the realistic impression to be in the actual tank. The motion of the turrets is observable through the periscopes. Noise (motor generator, firing etc.) is simulated to a realistic level. This necessitates the use of the headsets by the crew. They allow for training in intercom and RT procedures.
• Battlefield Simulator
  The simulation of the environment, performed by the computer systems, includes targets with various flight profiles, as well as background scenery.
  The trainee observes the battle scene environment on the radar screens and through the periscope. The simulated radar pictures show the same effects of clutter, screening, multi-path, ECM and glint as a real radar.
  The optical pictures are fully correlated to the situation on the radar; computer-generated imagery is presented on a graphic display and is observed through the periscopes. The radial velocity of the target is audible by the Doppler tone in the crew's headsets.
• Instructor Facilities
  Photo: Through view of the Computer Trailer of MLT-1. This is the instructor's domain; the instructor keeps control over both trainers. The Ferranti 1600B computer can be seen behind the console.

  One instructor has the supervision over the simultaneous training of three teams. Besides this instructional task, he records the training results and evaluates the progress of the trainees. A number of subtasks, traditionally performed by the instructor, have been transferred to the software of the MLT computer system: the Computer-Assisted Instruction (CAI) software.

  The integration of CAI in a real-time system environment gives advanced training capabilities. Using the facilities on his console (BIC), the instructor is able to pay full attention to teaching and attendance. He will select his lesson material from the computer libraries for the particular training level. During the session, the individual achievements of the teams are continuously monitored by the CAI software.
  The instructor is provided with the pictures of radar and periscope, as presented to any selected crew.

Mobile and Stationary Version

Computer Assisted Instruction

• giving each crew a tailored training,
• using objective criteria for evaluation during and after the exercise,
• giving the instructor freedom to pay maximum attention to the progress of each student individually.

The assignment of further steps (part of a training session) is highly automated. The trainee is not degraded to a robot; in a number of cases he has influence on the kind and the pace of the development of the problems. The CAI provides an adaptable training, making allowance for what the individual trainee can digest and what he prefers to rehearse. Moreover, the instructor can pay maximum attention to the progress of each student individually.

The lessons are prepared off-line, and are composed of libraries of flight profiles, targets and backgrounds. The preparation includes the recording of desirable and necessary reactions of the crew to an attack. These recordings are used as reference for the CAI software in evaluating the action taken by the trainees. This is practically the only way to evaluate the training results with objective criteria.
The uniform structure of the CAI software facilitates the adaptation of the lessons to the latest views of didactics or tactics.
The trainees' reactions are recorded for review after conclusion of the exercise; a printout is made for direct evaluation, while a magnetic recording is kept for long-term evaluation.

The instructor has a direct survey of the situation through the information presented on the displays of the BIC, viz.:

• the PPI (search radar display),
• the A-scope (track radar display),
• the screen with one of the periscope views (commander or gunner),
• the lamps indicating the status of the controls in the turret.

Software Elements

FLEXIBILITY

The software renders the MLT the flexibility necessary to keep the exercises up to date. The Application Software developed under system responsibility of LEOK, consists of the following elements, defining various modes of operation of the computer system.

PREPARATION

Exercise libraries contain the parameters for the training software, while their preparation does not require any specialised programming skills. The libraries are composed of the following files:

• flight profiles,
• environment data, including optical and clutter data,
• target shapes, defined in three dimensions for the pre-calculation of the target contours according to the flight profiles,
• exercises.

The training staff must decide the scenario of the exercise and compose the above files. The files are prepared with the aid of a graphical tablet and display terminal in a conversational mode with the computer system; they are stored on disc.

TRAINING

Used in the training mode of operation, the main program functions are:

• Simulation of weapon system performance, including the generation of pictures for the radar and optical displays, the simulation of the various servo loops (in antennas, periscopes, turrets, guns and fire control computer), and the simulation of audio;
• Simulation of battlefield environment:
  • terrain simulation for periscopes and radar (including ground and rain clutter and dazzling sunlight),
  • target simulation for periscopes (silhouette) and radars (PPI, A-scope, Doppler audio, IFF and ECM);
• CAI functions, including the control of the simulated battlefield environment, and the sensing of the weapon system reactions in conjunction with the crew to the ~CAI step instructions. They also record the progress made by the crew and the communication with the instructor.

EVALUATION

The digital magnetic recordings of the training results are available for further evaluation of the long-term progress made by the trainees individually.

GENERAL SUPPORT

The general support software furnishes reprogramming facilities for the organisational, structural and arithmetic part of the software (the "instructions"). These facilities include the standard software supplied by the computer manufacturer (Fixpac Assembler, CORAL 66 Compiler, and associated routines), and LEOK-designed software (integrated in the EOS-operating system; this is software that controls the execution of computer programs and provides debugging, input-output control, compilation, etc.).

TEST

The test mode of operation assists in fault-finding and repair work, while providing a full check on the operation of the various system modules. In the event of a failure, test programs indicate passively or actively the type of failure, so that the faulty module may be replaced.

Hardware Elements

COMPUTER

The system employs the Ferranti FM1600B computer: a 24-bit parallel mode computer with a 3-address instruction code, and a 44K word internal core store. For input/output operations, 22 interface channels are available.

DISC UNIT

The background store for the software package and real-time library data is a dual Hewlett Packard HP 7900A disc cartridge system with a total capacity of 3.2M words.

LINE PRINTER

This produces hard copies of all relevant information, including the lesson reports. The Data Products DP 2310 line printer operates at speeds between 350 and 1100 lines per minute.

SIMULATION ELECTRONICS

Under software control the simulation electronics generates the video for the various displays, and interfaces switches and indicators. The unit, designed and manufactured by LEOK, includes:

• radar target and clutter generator,
• periscope image generator,
• analogue 110 interface,
• switches/indicators 110 interface,
• real-time counter and antenna bearing simulator,
• 'tank logic' microprocessor (delegation of special functions to reduce main computer time load),
• digital audio simulator,
• on-line PROM programmer for loading of special programs and data for the simulation electronics.

INSTRUCTOR'S CONSOLE

Supervision of the training and control of the exercise are performed via the BIC, designed and manufactured by LEOK. The status of the training system is monitored via various indicators and displays. These are a conversational text display, video displays (search and tracking radar) and a graphic display (periscope), designed and manufactured by Signaal (HSA B.V.).
A headset is used to simulate both tank intercom and ~RT communications.
A digital cassette recorder is available for the storage of selected exercise results for analysis at a later date.

INTERFACE CABINET

This unit provides an analogue and digital multiplexing system between the Simulation Electronics and the three independent training turrets, reducing the number of cables between the two trailers of the mobile MLT.
The unit is of LEOK design and manufacture.

TRAINING TURRETS

Each MLT comprises three training turrets designed and manufactured by Signaal. They are exact replicas of the simulated weapon system. The turrets are connected to the air-conditioning system.

Summary of Features

General

• Computer-Assisted Instructions (CAI).
• One instructor only.
• Three independent turrets.
• Targets:
  • 8 ground/air targets, which can be distributed at will over the 3 turrets,
  • presentation for radar and periscopes with correlated positions,
  • echo-strength adapted to range, aspect and noise fluctuations,
  • radar presentation adapted to signal-to-noise ratio and the presence of multipath,
  • optical aspect adapted to position, course, roll and pitch of targets.
• Terrain:
  • one common optical background for the 3 turrets,
  • one common ground-clutter map for the 3 turrets,
  • separate rain-clutter map for each turret; this map can be altered during the exercises (real-time),
  • automatic optical and radar screening of targets by objects on the terrain.
• Optical simulation:
  • digital vector displays,
  • 1024 x 1024-point grid,
  • maximum 2047 vectors per display frame (6 independent displays),
  • frame refresh rate 60 Hz,
  • picture refresh rate 20 Hz.
  The pictures are viewed via special optics, which simulate the periscope with respect to eyepiece, magnification and view-angle.
• Optical target presentation:
  • synchronised with radar target simulation,
  • adjusted to target and periscope movements and magnification,
  • presented as silhouettes, background presented by characteristic contours for position
  • identification.
• Support facilities for the composition of exercises:
  • Any type of target definition,
  • Any flight profile,
  • Any optical and correlated clutter background,
  • Any type of exercise.
  The standard libraries are flexible and can be expanded as required.
• Realistic audio simulation of shots, turret and gun movements and power unit.
• Simulated degradation of the weapon system.
• Capabilities for practising RT procedures.
• A rapid re-availability and a high MTBF are assured through the use of reliable solid-state electronics.

Mobile Version

• Both trailers are air-conditioned; the Computer Trailer is fitted with a special humidity-control installation. The ambient temperature is maintained above 10 C.
• The temperature in the turrets can be controlled between 20 C and 40 C.
• Special safety precautions in the vehicles and turrets, including smoke detectors and emergency exits.
• Weight per vehicle: about 23,000 kg.
• Length: 15 m, height: 3.90 m, width: 2.50 m.
• Total power consumption, including air-conditioning: max. 75 kVA.