Loran-C and eLoran Timing Receiver

OEM version PCB

This latest version of UrsaNav’s “Mitigator™“ series LF receiver is provided as an OEM module for further integration into customer applications. The UN-151B receiver uses an external E-field or H-field antenna that is connected to the OEM module using the same antenna connector. The receiver provides 10MHz and 1PPS timing signals that are aligned to UTC that is derived from received signals, as well as NMEA compliant data logs.

Key Features

  • Small form factor
  • NMEA messaging
  • Complete range of integration capabilities
  • Software configurable
  • Intuitive user-friendly graphic display software
  • Loran-C, eLoran, Chayka
  • Flexible SDR architecture


View the full product description


The UN-151B is the latest version of UrsaNav’s Mitigator™ series Low Frequency (LF) receivers designed as an OEM module for further integration into your applications. This OEM module provides precise time, frequency, and data channel demodulation from Loran-C or eLoran systems. The receiver is capable of processing Chayka and other low or medium frequency sources.

The UN-151B is the only commercially available timing receiver module that meets the stringent European Telecommunications Standards Institute requirements for Primary Reference Clocks, the Stratum–I frequency requirements, and provides traceability of time to within 50 nanoseconds of UTC. Built-in future–proofing ensures capability to track next generation LF signals with advanced waveforms and enhanced data channel capability.

As solutions experts for LF Position, Navigation, Timing, Frequency, and Data technology; UrsaNav has you covered from transmission to reception. Our turnkey solutions include system design, timing and control equipment, advanced data channel techniques, and differential Loran reference equipment.

Download the UN-151B Product Fact Sheet (PDF)

Technical Specifications

  • Timing Specifications: ETSI EN300 462-6-1 / ITU G.811
  • Maximum Time Interval Error: < 50ns from UTC; < 25ns for 100s intervals; < 100ns for intervals <1000s
  • Hold-over: < 5 μs / 24 hrs
  • Timing source: 1 to 3 radio transmitters with automatic handover
  • Time to First Fix: 30 seconds
  • Position Update Rate: 1 Hz
  • Accuracy (95%): 10-20m Stand-alone eLoran absolute positioning accuracy in differential eLoran mode
  • Stations tracked: All in view
eLoran Engine
  • Sensitivity: 30-120 dB μV/m
  • Dynamic Range: 96 dB
  • Signal Processing: Band pass/notch filtering, cross-rate cancellation, moving average TOA integration
  • Loran Data Channel: Eurofix, 9th / 10th pulse
  • Heading: <1 degree with H-field antenna
  • Dimensions: 100 x 158 x 33 mm
  • Weight: 198 g
  • Input Voltage: +5VDC (+/- 5%)
  • Power Consumption: 14 W
  • Dual Serial ports (TTL Level)
  • 115200 baud
  • NMEA Messaging
  • GPIO Port
    10 MHz frequency output
  • 1 PPS eLoran UTC output
  • 10 MHz frequency input
  • 1PPS input
  • Feature connectors
  • Optional USB
  • Optional Ethernet
  • Operating Temperature: -40°C to +65°C
  • Storage Temperature: -50°C to +75°C
  • Humidity: 95% noncondensing
  • Dual Core ARM/DSP Software Defined Radio
  • Firmware upgradable
  • On Board FPGA and flash memory
  • Meets RTCM SC127 draft MPS spec
  • Meets ETSI PRC requirement
  • Meets Stratum-I frequency spec
  • eLoran UTC recovery
  • Full eLoran, Loran-C, Chayka capable
  • Differential Loran capable
  • Position, Frequency, Time & Data
  • GNSS Integration ready
  • Stand-alone, ASF and Differential Positioning
  • User friendly intuitive GUI for Windows XP/7
  • Allows monitoring, archiving and control of UN-151 series
    • Time of Arrival trending
    • Position Scatter plot
    • Loran Data
    • Channel display
    • Command interface
    • Replay of recorded data
    • FFT