Terminal High Altitude Area Defence (THAAD) is a US Army anti-ballistic missile system designed to shoot down short, medium, and intermediate ballistic missiles in their terminal phase using a hit-to-kill approach. The interceptor missile carries no warhead, but relies on the kinetic energy of the direct impact to destroy the incoming threat. Verotec has supplied Lockheed with custom 4U, 750mm deep 19 inch VPX chassis that houses a signal integrity testing subsystem, the reconfigurable and analogue Self Test Subsystem. The STS chassis validates the signal outputs from other parts of the control system to ensure their integrity.
Signals enter the STS through four high density circular connectors in the front panel. They are initially processed through FPGA-based cards, which are cooled by one of two integral high performance fan trays mounted in the base of the unit. The top and base of the chassis are fitted with high perforation covers to maximise airflow through the cards. The processed signals from the FPGA cards are propagated to a 3U 9 Slot VPX (VITA 46) system at the rear of the unit, which is housed in a heavy-duty KM6-HD card cage, powered from a 300 Watt pluggable PSU and cooled by the second dedicated fan system. The rear panel also provides cut-outs for DIN, USB and RJ45 connectors. Signals exit the VPX section of the system to a DMM and oscilloscope, generating external data that allows the operating personnel to confirm their integrity against reference values as part of the pre-launch sequence.