NEYRPIC ACS 450 is a satellite tracking system designed, manufactured and distributed by Alstom. It is destined to be mounted on all parabolic antennas covering frequencies from L to Ku band, for tracking geostationary satellites in a stable or inclined orbit. Specifically designed for harsh environmental and operating conditions, the 450 series can also be used with mobile antennas on land vehicles.


General Description

The NEYRPIC®ACS 450T is offered in two form factor; Rack – NEYRPIC®ACS450TR, Cabinet – NEYRPIC®ACS450TC. Both products are composed of :

  • The NEYRPIC®ACU 450T antenna control unit
  • The set-up software: NEYRPIC®ACU Param450T
  • The Motor Drive Unit

They interface with the following antenna peripherals:

  • Beacon receiver
  • Motors for the azimuth, elevation and polarisation axes
  • Optical positions sensors
  • Limit switches and interlocks
  • Compass
  • GPS receiver
  • Temperature gauge
  • Tilt Sensors
  • Motorization emergency stop button
  • LNA Alarms
  • RF switches


  • Manual axis control
  • Unit heater
  • NEYRPIC® IHM 450T dialog box

Antenna Control Unit: NEYRPIC®ACU 450T

The NEYRPIC® ACU 450T antenna control unit is the main controlling device in the NEYRPIC®ACS450TR and NEYRPIC®ACS450TC. While monitoring system status, the ACU allows the operator to have access to the following features:

  • Speed mode: Each motor can be operated independently in low /high speed.
  • Position mode: Manual entry of the AZ/EL position.
  • Satellite homing: The ACU has 32 pre-programmed satellite orbits parameters. Two sets parameters are available for each of the 32 satellites. They can be loaded via the Ethernet port. 64 RF configurations are also available.
  • Satellite acquisition: After homing, satellite acquisition is made using a raster scan.
  • Step tracking: After homing and acquisition of the satellite, tracking is made by configurable period intervals.
  • Calculated tracking: When the signal is no longer considered as acquired, the system switches over to calculated tracking which operates on orbit parameters from Eutelsat, Norad TLE or CNES.
  • Orbit Prediction Tracking: Intelligent Progressive Orbit Prediction (I.P.O.P.) tracking allows efficient orbit prediction and tracking up to 7 days without beacon signal.
  • Standby Mode: The motors are stopped.
  • Survival/Transport Mode: The motors are stopped with the antenna in a specific position.

NEYRPIC®ACS 450T: Other features

Beacon receiver control: via an RS232 link the ACU can control most commonly used receivers such as SMP, Vertex DTR, Novella, MITEQ, etc. Other models can be added upon request.
Managing multi-band antennas: the ACU automatically adapts its satellite search and tracking parameters according to the frequency band being used.
Anti-Secondary lobe: Broad scan algorithm is executed around theoretical position to determine the main lobe position.
Peripherals: Interface with instrumental peripherals (GPS, Magnetic Compass, inclinometer) to optimise satellite tracking with a static or dynamic plate compensation.
LNA Monitoring: LNA monitoring through dry contacts.
RF switches: Possibility to control and retrieve status of 2 RF switches.
RF inhibition: Output of an SPDT reflecting if RF transmission is allowed according to antenna position.
Automatic detection of movement error: Monitors antenna movements according to control commands.
Intelligent travel management: selects proper travel direction (CCW, CW) upon calculated satellite drift box before pointing to a satellite.
Customers DIO: 4 24V DI and 6 dry contact connections are available for customer use.

NEYRPIC®ACS450T: Interface, Monitor and Control

NEYRPIC® M&C interface is the dedicated control application for the NEYPIC®ACS450T. Software updates are downloaded via the CAN bus or the RS232 port. The NEYRPIC®HMI450T is a complete communication tool with the NEYRPIC®ACS450T. All inputs and outputs are short circuit protected and diagnosable.

NEYRPIC®ACU Param450T: Backup/Restore software tool

The NEYRPIC®ACU450T is delivered with its set-up software tool which allows for an easy configuration and installation using a PC. The NEYRPIC®ACU param450T allows backup/restore of all parameters, as well as read-write access to them:.

  • On-line modification of the ACU parameters.
  • Saving and backing up all ACU parameters to a file
  • Instant display and modification capability of the parameter file
  • Restoring into an ACU all parameters.

This software, developed in Java, runs under various operating systems such as Windows and Linux.

NEYRPIC®ACS450T power unit

The servo drive unit is included in the NEYRPIC®ACS450TR and the NEYRPIC®ACS450TC. This servo drive unit main features are:

  • Control of a 24V AZ motor with a frequency converter
  • Control of a 24V EL motor with a frequency converter
  • Control of a 24V POL motor
  • Motorisation Stop mounted on front (ACS450TR) or side (ACS450TC)
  • Axis limit switches
  • Power supply 24V DC or 110/220v AC 50/60 Hz

Position sensors

The ACU can read from the three position sensors (AZ, EL and POL). These sensors may use different technologies:

  • 12-bit optical absolute encoder (single or multi turn)
  • 18-bit optical absolute encoder
  • 34-bit multi-turn encoder

NEYRPIC®IHM 450T dialog box

With its large display and its four buttons, this HMI is a real communication tool with the NEYRPIC®ACS 450T. It allows full control of the whole system, displaying the operating modes, the antenna positions and the beacon signal level. Its rugged ergonomic housing enhanced the ease of use of the NEYRPIC®ACS450T in any rough environment.


  • Backlit screen: 110mmx110mm
  • 4 illuminated buttons on the front panel
  • 80dB buzzer
  • Communication via CANOpen bus
  • French/English display
  • Protection index IP67

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