The terrestrial navigation system is a national core infrastructure that provides position, navigation, and timing needed in various public and private fields such as finance, power, and transportation.
The advanced terrestrial navigation system is a backup and substitute navigation system that improves the position accuracy and stability, which are shortcomings of the existing Loran system, and can provide position, navigation, and timing even when GPS is disturbed.

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eLoran System

eLoran Signal Generation & Control System

[DAR-eL100-S]
The system provides 100kHz envelope eLoran signal generation function for advanced terrestrial navigation, LDC (9th Pulse/Eurofix) modulation/demodulation function for processing correction information, time correction function for system timing synchronization, and high-power transmitter interface function.

This system has the function of ensuring service continuity by monitoring and controlling the signals transmitted from the redundant system.

Specifications

• ECD control performance: <±2.5μs

• TOT control performance: <50ns

Functions

[Signal generating]

• Generating eLoran Pulse Signals Synchronized to UTC

[LDC]

• 9th Pulse modulation and demodulation

• Eurofix modulation and demodulation

[Signal Measurement]

• Measuring Transmission Signal Quality(Occupied BW, ECD, SNR, etc.)

[TOT Control]

• TOT control for UTC time synchronization of transmission signal

[Control & Monitoring]

• Monitoring of external reference timing supply system status

• Control(GRI, Phase Code, ECD, TOT, Blink Control) & Status Monitoring of eLoran Exciter

• Control & Status Monitoring of high-power transmitter

• Remote control using eLM messages

• Switching function of a redundant system

• Monitoring of LDC message status

eLoran Exciter

[DAR-6000T]
The eLoran Exciter is a device that generates an eLoran Pulse signal that inserts LDC (Loran Data Channel) information based on the received reference time information and then transmits it to the eLoran transmitter.

The eLoran Exciter performs a TOT automatic control function based on the received TOT status value to control the error between the time of the antenna transmission signal and the reference time to be within the error tolerance range.

The eLoran Exciter performs the function of measuring the signal quality of the output signal.

Specifications

• ECD control performance: <±2.5μs

• TOT control performance: <50ns

• Input signal: 1PPS, 10MHz, IRIG-B, TOT Value, eLM Message, eLoran Feedback signal

• Output signal: eLoran signal (LVDS)

Functions

• GRI, Phase Code, TOT, ED, ECD, Blink control functions

• LDC(Eurofix and 9th Pulse) modulation/demodulation functions

• Signal quality measurement functions such as ECD, SNR, occupied bandwidth, etc.

• Function of eLM message reception and control

UTC Synchronization System

Loran-C UTC timing Synchronization System

[DAR-6100UTC-H]
This system is to synchronize the transmitted signals of the Pohang and Gwangju transmitting stations belonging to the Loran-C international cooperation chain to Universal Coordinated Time (UTC), by using GNSS (Global Navigation Satellite System).

This system generates a reference time using the Holdover function when GNSS signals are unavailable due to GNSS interference, etc.

Specifications

• Timing synchronization performance :

< 50ns to UTC @GNSS Locked

< 50ns(rms) for 14 days @GNSS Unlocked (Holdover)

• GNSS CV Timing comparison performance : < 10ns for 1 day

• Loran-C signal SZC detection resolution: <2ns

• TOT control performance: < 10ns

• Input Signal: GNSS signal, Loran-C Feedback signal

• Output Signal: 5MHz Sinewave

Functions

• Generating a reference timing(1PPS, IRIG-B, 10MHz) synchronized to UTC

• Timing error measurement and control of the reference timing generation system

• Comparison of timing with UTC KRISS using Common View

• Holdover using cesium atomic clock

• TOT control (Auto/Manual)

• SZC detection

• Blink detection and status information provision

• Transmission signal quality measurement function based on SAE9990 standard (ECD, SNR, Droop, PKI, PKP, etc.)

• Status monitoring function through GUI

• Remote control and monitoring functions

• Log data storage and inquiry function

• Dual system structure (main and standby device design)

TOT Control Unit

TOT Control Unit

[DAR-6100T]
The TOT control unit receives the reference time information (IRIG-B, 10MHz, 1PPS) from the reference timing generation unit and generates the UTC-based GRI chain Timing.

This unit uses the automatic TOT control function that controls the frequency and phase of the output signal (5MHz Clock) based on the generated UTC GRI Timing to ensure that the time of the Loran-C signal transmitted from the transmitter is continuously synchronized with the UTC time.

This unit performs a signal quality measurement function based on the SAE9990 standard for the transmitted Loran-C signal.

Specifications

• SZC detection resolution: < 2ns

• TOT control performance: < 10ns

• Input signal: 1PPS, 10MHz, IRIG-B, Loran-C Feedback signal

Output signal : 5MHz(Sine wave)

Functions

• Transmission signal quality measurement function for SAE9990 standard: First Pulse and 8 Pulses quality measurement of Group A/B

• Signal quality measurement functions such as ECD, SNR, Droop, PKI, PKP, and Occupied Bandwidth for the transmitted signal

MF R-Mode System

[DAR-6200RM-S]
This system is a terrestrial backup navigation system for PNT (Position, Navigation, Time) services required for ship operation and berthing in the event of GPS interference and hacking.

It is a terrestrial navigation technology that transmits a signal that combines an MSK signal and two CW signals at a frequency of 300 kHz, and is one of the alternative navigation systems that stably provides PNT services.

Specifications

• Timing synchronization performance between MF R-mode transmitters:

<10ns @GNSS Locked

<20ns(rms) for 15 days @GNSS Unlocked

• R-Mode signal generating : satisfied MF R-Mode Modulator Spec.

• DGPS MSK modulation/demodulation : satisfied ITU R. M-823-3 standard

• RTCM demodulation : satisfied RTCM SC-104 standard

• TOT control performance: <±5ns

• Input signal : GNSS Signal, RTCM Data, MF R-Mode Feedback Signal

• Output Signal : MF R-Mode Signal

Functions

[UTC Timing Synchronization System]

• Generating a reference timing(1PPS, IRIG-B, 10MHz) synchronized to UTC

• Timing error measurement and control of the reference timing generation system

• Timing comparison between transmitters using Common View(CV)

• Holdover using cesium atomic clock

[MF R-Mode Exciter]

• MF R-Mode signal generation

• MSK signal modulation and demodulation

• CW1/2 signal generation

• TOT control(Auto/Manual)

• Signal quality measurement such as ECD, SNR, Occupied Bandwidth for the transmitted signal

[Transmitter Control Unit]

• Control & Monitoring Transmitter system : output path, switching mode (Auto, Manual) and output On/Off

• Transmitter remote control

MF R-Mode Exciter

Brochure

[DAR-6200T]
The MF R-Mode Exciter is a device that receives a reference timing data from a reference timing generator, generates an MF R-Mode signal that combines an MSK signal and two CW signals, measures the quality of the output signal, and controls the generated CW signal to be synchronized to the reference time through TOT control.

시스템 사양

• MF R-mode Modulation

– MSK Signal Frequency control : 283.5kHz ~325kHz @1Hz Step

– RTCM Bit Rate setting : 50/100/200bps

– MSK Signal Timing control : 1ns Step based on MSK phase

– CW1/2 Signal Frequency control : 283.25kHz ~325.25kHz @1Hz Step

– CW1/2 Signal Timing control : 1ns Step based on CW phase

– Amplitude Control : 0~100%, 1% Step

• External 1PPS Synchronization

– MSK Bit timing uncertainty : <1ns @ MSK Phase vs. 1PPS

– CW1/2 Signal timing uncertainty : <1ns @CW Phase vs. 1PPS

• CW Phase Estimator