Profile: Servo Corp. Of America designs, develops & manufactures components for satellite attitude determination, earth resource monitoring, infrared detectors & radio navigation systems for harbors and airports. The bearing display/control unit is installed at the operations site and connected via 4 wire voice grade telephone line circuit to the receiver/bearing processor unit located at the antenna site. It is a rack-mounted unit which is similar in physical appearance to the receiver/bearing processor assembly. The unit contains all circuits necessary to remotely control tuning of the receiver and to receive and display the receiver channel frequency as well as status & bearing data through the use of the modem and associated 4-wire telephone circuit. Mini horizon crossing indicator sensor consists of a lithium tantalate pyroelectic detector mounted in an aluminum housing. The detector is a 1mm diameter octagon configured in a voltage follower circuit. This circuit consists of the pyroelectric crystal connected to a JFET, with a 1x10Ell ohm source resistor. A lens designed for use in the 14um to 16um spectral band is mounted in the housing.