Micro-Transcoder 10-Channel GPS Simulator and Assured-PNT Transcoder Module
1-inch square 10-channel real-time GPS simulator module that transcodes secure PNT data into a standard GPS L1 RF signal for legacy receivers.
- Simulator channels
- 10-channel
- Transcoding latency
- less than 100 ms
- UTC 1PPS timing-transfer accuracy
- better than 5 ns
- Timing accuracy
- 5 ns
Overview
The VIAVI Micro-Transcoder is a full-constellation, stand-alone, real-time 10-channel GPS simulator in a 1-inch square module. It is designed to retrofit existing GPS equipment with secure and assured PNT capability without additional interface hardware.
The module is spliced in between the existing antenna and the user's GPS receiver. It takes the output of a secure PNT source such as an INS, SAASM or M-code receiver, or a concurrent GNSS receiver, and encodes (RF modulates) the baseband PNT and UTC timing information into a standard GPS L1 RF signal that any legacy GPS receiver can receive. In this role the unit can act as a GPS firewall to identify and block jamming and spoofing attempts, and can provide an alternate PNT source during fully GPS-denied operation.
The Micro-Transcoder is based on the CLAW GPS Simulator and RSR Transcoder technologies. It combines the 10-channel real-time simulator with an integrated high-stability timing reference and an internal GNSS receiver that monitors the RF output signal for quality and accuracy. Applying 3.3 V power is sufficient for the unit to transmit a GPS L1 RF signal carrying UTC time, position, velocity and heading.
Interfaces and operation
Baseband NMEA or SCPI PNT information and external 1 PPS timing pulses are received through two serial ports and a 1 PPS port, allowing direct connection to external GNSS or INS PNT sources. The baseband signals are transcoded into GPS L1 RF with typically less than 100 ms latency, and UTC 1PPS timing-transfer accuracy is generally better than 5 ns. Setup and location information can optionally be stored in internal non-volatile memory.
Software and general-purpose use
The module can also be used as a general-purpose GPS simulator with a built-in GPS Disciplined Oscillator (GPSDO). It is supported by the SimCon application software, which controls all simulation aspects, creates and stores simulation vector commands, and tests user equipment for leap-second and GPS week rollover compatibility. No external PC is required for operation, which simplifies embedded use.
Key Features
- Embedded NMEA encoding to GPS L1 RF
- Upgrades existing GPS systems to INS, SAASM, M-Code or concurrent GNSS PNT sources
- Functions as a GPS firewall to harden against spoofing and jamming
- Serves as an alternate PNT source during fully GPS-denied operation
- Full-constellation, stand-alone, real-time 10-channel GPS simulator
- Built-in GPS Disciplined Oscillator (GPSDO)
- Internal GNSS receiver monitors the RF output for quality and accuracy
- 0.97 x 0.97 x 0.4 inches in dimension, 0.95 W
- 5 ns timing and 1 m positioning accuracy typical
- Leap second and Week Number Roll Over testing of customer GPS receivers
- Can be used as a low-cost general purpose GPS simulator
- Operates without an external PC by applying 3.3 V power
- Setup and location information can be stored in internal NV memory
- Supported by SimCon application software
Specifications
| Simulator channels |
10-channel
Full-constellation, stand-alone, real-time GPS simulator
|
|---|---|
| Transcoding latency |
less than 100 ms
Typical
|
| UTC 1PPS timing-transfer accuracy |
better than 5 ns
Generally
|
| Timing accuracy |
5 ns
Typical
|
| Positioning accuracy |
1 m
Typical
|
| Built-in GNSS monitoring receiver | 72 channel gen-8 GNSS receiver |
| 1 PPS output | One 3.3 V CMOS 1 PPS output |
|---|---|
| 10 MHz output | One 10 MHz CMOS 3.3 V output, disciplined by external 1 PPS reference |
| RF output | One RF GPS L1 C/A code, -105 dBm to -128 dBm |
| Spectral Purity (1 MHz to 13.2 GHz) | < -30 dBc in-band (L1, ±20 MHz), < -70 dBm out-of-band |
| Harmonics of L1 (1.57542 GHz) | < -140 dBm |
| Data/Power Connectors | Standard DIP 100 mil footprint, can be soldered or socketed into customer PCB |
|---|---|
| Serial Control | SCPI-99 Control at 9.6 K, 19.2 K, 38.4 K, 57.6 K, 115.2 K |
| External GNSS receiver compatibility | Any NMEA compatible source, direct control of Rockwell Collins GB-GRAM and MicroGRAM SAASM GPS, and u-Blox GNSS receivers, supports Satelles/Iridium-STL receivers |
| SCPI Control/Monitoring Port | Compatible to any terminal program, SimCon, and GPSCon, NMEA output sentences |
| Inputs | Two serial ports and 1 PPS port; baseband NMEA or SCPI PNT information and external 1 PPS timing pulses |
| Dimensions | 0.97 x 0.97 x 0.4 inches |
|---|---|
| Power consumption | 0.95 W |
| Supply voltage | 3.3 V |
| Operating Temperature | -40°C to +75°C |
| MTBF | >600,000 Hours |
Specifications are taken from the manufacturer's documentation. See the datasheet for complete and current values.
Applications
- Defense
- 5G Communications
- SATCOM
- Transportation
- Data Center
- Energy
- Financial
- Critical Infrastructure
- Retrofitting legacy GPS equipment with assured PNT
- GPS receiver leap-second and week rollover testing
Options & Accessories
| Option | Description |
|---|---|
| 1005240 | Micro-Transcoder w/o TCXO - RoHS — Micro-Transcoder configuration without TCXO |
| 1005220 | Micro-Transcoder w/TCXO – RoHS — Micro-Transcoder configuration with TCXO |
| 1005221 | Micro-Transcoder HP w/ TCXO - RoHS — High Power (HP) Micro-Transcoder configuration with TCXO |
| 1005250 | Micro-Transcoder TCXO Evaluation Kit — Kit contents: Micro-Transcoder module, LC XO PCBA, Micro-Transcoder Top Shield, Micro-Transcoder Bottom Shield |
| 1005278 | Micro-Transcoder Evaluation Kit w/o Micro-transcoder — Kit contents: Micro-Transcoder Evaluation Board |