New JLT Micro-Transcoder provides GPS firewall retrofit

December 5, 2018  - By
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Jackson Labs Technologies Inc. (JLT) released its tiny, new Micro-Transcoder, a full-constellation, stand-alone, real-time 10-channel GPS simulator. The unit can act as a GPS firewall to identify and block jamming and spoofing attempts, and to provide an alternate PNT source during fully GPS-denied operation.

JLT is a designer and manufacturer of GNSS, timing and frequency equipment.

Photo: JLT

Photo: JLT

The one-inch-square Micro-Transcoder module allows glueless retrofitting of existing GPS equipment by upgrading systems with secure and assured positioning, navigation and timing (PNT) capability, the company said. It achieves hardening of the customers’ GPS equipment by splicing the unit in between the existing antenna and the users’ GPS receiver.

It takes the output of any secure PNT source — inertial navigation system (INS), SAASM, M-code, Iridium STL, or concurrent GNSS receiver — and encodes (RF modulates) the baseband PNT and UTC timing information into a standard GPS L1 RF signal.

This RF signal can then be received by any legacy GPS receiver.

The unit is based on JLT’s CLAW GPS simulator and RSR transcoder technologies, and includes a stand-alone full-constellation 10-channels real-time GPS simulator with integrated high-stability timing reference, as well as an internal GNSS receiver for monitoring the RF output signal for quality and accuracy.

The unit will transmit a standard UTC time, position, velocity and heading GPS L1 RF signal by simply applying 3.3V power to it.

The Micro-Transcoder can also be operated as a generic high-performance GPS simulator with built-in GPS Disciplined Oscillator, and is supported by a comprehensive free Windows application program downloadable from the JLT website.

The Windows application allows control of all the simulation aspects, creating and storing simulation vector commands, and testing user equipment for leap-second and GPS week rollover event compatibility to identify weaknesses in user equipment.

The unit does not require a PC to be connected to it to function. This makes embedded operation as easy as applying power, and connecting the units’ RF output to the antenna input of any GPS receiver.

By generating a legacy RF GPS signal from any secure PNT source, the Micro-Transcoder allows users to maintain their investment in fielded legacy GPS equipment. Example applications include retrofitting financial transaction time servers with CSAC or rubidium atomic clock holdover capability, and adding GPS RF output capability to concurrent GNSS receivers to allow reception of L1, L2, L3, L5 GPS, GLONASS, Galileo, BeiDou, QZSS, Iridium STL, or any other satellite-based navigation signal to legacy GPS receivers.

It can also be used to add inertial navigation system (INS) capability to vehicles and aircraft.

None of these applications require any modifications to be made to the legacy GPS receiver system; all configurations are done externally using the Micro-Transcoder Windows application or a standard terminal program, and on the assured PNT source.

A real-world customer application is a data-center where communications equipment required a GPS signal to operate. The user wanted to prevent vulnerabilities that an external antenna would have introduced. In this scenario, the Micro-Transcoder provided a fixed-position GPS RF signal to a number of the data centers’ GPS receivers, and allowed the GPS user equipment to operate properly without exposing it to the possibility of external jamming or spoofing.

At 0.97 x 0.97 x 0.4 inches and with less than 0.95W power consumption, the Micro-Transcoder is small enough to be designed into emerging assured PNT products, allowing them to communicate gluelessly to existing legacy GPS infrastructure.

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