Services
생활속의 위성항법, 보다 안전하게 제공하겠습니다!
Glossary
| Terminology | Definition |
|---|---|
| AECD | It stands for assigned envelope-to-cycle difference (ECD) and is the currently assigned ECD in the transmission station that is already assigned. The AECD needs to be consistent in order to manage NECD and CSECD. |
| Affiliated Agency | A national agency that operates the related chain stations or secondary stations. |
| Alpha Control (알파통제) |
Baseline control stations conduct baseline control through incoming data in control stations. |
| AUTM | It stands for authorized unusable time, which is a planned operation suspension period wherein users are informed of the purpose of and reason for the transmission suspension time. |
| Baseline UUT (기선 UUT) |
It is the baseline time when the prescribed scope of usage and degree cannot be used regardless of the reason. |
| BLL | Base Line Length |
| Blink | A repetitive ON-OFF pattern of the first two pulses in the master station signal, indicating that the baseline cannot be used (ON for about 2.5 seconds, OFF for about 2.75 seconds) |
| Blanking | It suppresses the transmission of one rate due to the periodic phenomenon that occurs when the double-launch transmission station needs to transmit pulse groups of different rates simultaneously (or almost simultaneously). During the overlapping period, only rate is transmitted; the other one is suppressed or not transmitted. There are two types of blanking: priority and alternate. (a) In the priority blanking, one rate is always blanked; (b) in the alternate blanking, two rates are blanked alternately. |
| CD | Coding Delay |
| CD | Coding Delay. The time the secondary station has to wait before transmitting and after receiving a pulse from the master station. |
| Chain UUT | It is the time when the prescribed scope of usage and degree cannot be used regardless of the reason. |
| CM | It stands for chain manager, and is the person who is responsible for supervising and issuing instant instructions for the daily operation of the Chain. |
| CSECD | Controlling Standard Envelope to Cycle Difference |
| CSTD | Controlling Standard Time Difference |
| COCO | The coordinator of Chain operations (COCO) is the supervisor of the Loran-C/Chayka System, and is responsible for the instant and daily supervision of the Chain. The designated position of COCO will be determined by the chain manager (CM). COCO is designated by the country that has the master station. |
| COCO | The Chain operations liaison officer (COLO) is the person who acts as the point of contact with overseas transmission stations within the Chain. |
| Coordinating State (협력국)국 |
It refers to member countries of FERNS who hold responsibilities for the regular operation/suspension plan for maintenance work |
| CS | It includes recognized coordinating states for the execution of accurate correction in practice when monitoring control station signals and parameters of the Chain members. |
| CSECD | It stands for controlling standard envelope-to-cycle difference (EDC), and is determined by the chain calibration and is managed by monitoring stations (control). |
| CSTD | It stands for controlling standard time difference and have two types of reference standard CSTD for a control station to compare the time difference observation in Alpha-1 monitoring stations (nominal and assigned). (a) Assigned CSTD: This figure changes according to the setting standard number (nominal CSTD) determined during chain calibration. Changing the assigned TD is a long-term control function based on instructions from the master station or control station. |
| Delta Control | It is a short-term baseline control conducted by the master transmission station. |
| ECD | It stands for envelope-to-cycle difference, and is the relationship between the phase of RF carrier wave and the original time of an envelope waveform. |
| Emitted ECD | It is the ECD extracted from the antenna's current pulse of the self-transmitting station displayed on EPA. |
| ED | It stands for emission delay, and is the the time interval between the master station and secondary station transmission in the same GRI determined during chain calibration. |
| EPA | Electronic Pulse Analyser. Electronic Pulse Analyzer |
| EUTM | It stands for emergency unusable time, and is an ATUM wherein users are not given sufficient explanation and information on the purpose. |
| ECD | Envelope to Cycle Difference |
| Field Strength | It is the strength of Loran-C/Chayka signals from each transmission station as measured by the monitoring station. |
| GRI | Group Repetition Interval |
| GRI | It stands for group repetition interval, and is the time interval of successive pulse groups, measured from the third cycle (or Zero Crossover) of the first pulse from a transmission station of a pulse group to the third cycle of the first pulse transmitted by the same transmission station within the next pulse group. All transmission stations within the Chain have the same GRI. The GRI, which is indicated with 10 μs, distinguishes the Chain; it is called Chain rate. The range of GRI is from 40,000 μs to 99,990 μs, increasing by increments of 10 μs. |
| INMARSAT-C | This equipment is one of the means of near real-time communication provided to perform general administrative tasks related to the operation of the Loran-C/Chayka joint chain and communicate the status of the chain. |
| LPA | It stands for local phase adjustment, and adjusts the timing of the master station’s emission time. The size of an LPA is at least ±20 ns. |
| Long-Term Control | It is the long-term baseline control conducted by the master station or control station. |
| MBK | It stands for momentary blink and is no longer than 60 seconds. |
| MOA | It stands for momentary off-air and is the launch hold time that is no longer than two minutes. |
| NECD | Nominal Envelope-to-Cycle Difference. ECD, which is maintained by the transmission station with the same existing transmission conditions during chain calibration, is the result of CSECD observed at the monitoring station |
| NECD | Nominal Envelope-to-Cycle Difference |
| Operating Agency | A government agency operating the master station of the affiliated chain (refer to Affiliated Agency). |
| PCI | It stands for phase code interval, and is the interval at which the phase code repeats. Loran-C phase repeats every GRI. |
| PKV | It stands for pulse peak voltage, and is taken from the antenna's current pulse of the transmission station and is displayed on the EPA. This is used as the transmission output indicator. |
| Pulse Leading Edge | A part from the start of Loran-C pulse to the peak (65 μs). |
| Pulse Trailing Edge | The late peak part of the Loran-C pulse. |
| Received ECD | The time interval between the envelope waveform of the original Loran-C/Chayka signal from each transmission station, which is observed individually at the monitoring station, and the phase of the RF carrier wave. |
| Responsible UUT | The baseline time when the prescribed range of usage and the prescribed accuracy cannot be used due to a malfunction of the transmitter. |
| RM | It stands for regional manager who is responsible for operating the chain properly. The RM must ensure the validity of communication between transmission stations. It is the responsibility of the affiliated states to command each transmission station and provide administrative support. |
| SC | It stands for station chief who is responsible for the daily operation of the station. a) SC (T): station chief of transmitting Loran-C or Chayka Station b) SC (CS): station chief of the control station c) SC (M): station chief of the monitor site. |
| Scheduled off-air fir maintenance | It is the scheduled maintenance and repair work for a transmission station for maintenance, and the operation/suspension period announced due to maintenance or repair work. |
| Standard Value | The reference value for each control parameter assigned by the control station. |
| Standard Zero Crossing | The positive zero crossing at the 30 μs point of the antenna's current wave shape in the positive phase code pulse. This zero crossing is phase-locked to the cesium time standard of the Loran-C transmission station. The standard zero crossing is used as the timing standard for measuring the Loran-C signal interval. |
| TD | Time Difference |
| TD | It stands for time difference, and is the time interval between the signal reception at the monitoring stations of the master station and secondary station, which have the same rate. |
| TINO | Timing Interval Number. The time interval between the transmission station's internal timer signal and the received signal. |
| Unmanned | A facility where workers are assigned to manage different transmission station. These workers are normally near the facility. |
| Unwatched | Although the equipment and baseline status are not monitored by an operator at all times, an operator is normally stationed in the facility. |
| UTC | It is the coordinated universal time or or universal time coordinated used as the signal reference time. |
| UUT | It stands for unusable time, and is the Loran-C or Chayka Station's time where transmission is subject to suspension due to abnormal signals that require a blink or other reasons. |
| Watched | A facility where a worker is generally stationed to monitor the equipment/baseline status 24/7. |
