GB 14391-2026Technical specifications for 406 MHz distress beacons (English PDF)

5.1 System Requirements

5.1.1 Essential Functional Components A position indicator should have at least the following functional components.

a) Digital information generator;

b) Modulator and 406MHz transmitter.

5.1.2 Digital Information Generator

5.1.2.1 Basic Requirements The digital information generator, used in the keying modulator and 406MHz transmitter, should transmit the digital information content defined in 5.2.

5.1.2.2 Repetition Period 5.1.2.2.1 Except for ELT(DT), the repetition period of other position indicator signals is not fixed and should be randomly distributed between 47.5s and 52.5s, with an average interval of It lasts for 50 seconds. 5.1.2.2.2 For stand-alone ELT(DT) in PDF-2 that does not contain 3LD, the repetition period shall meet the following requirements.

a) Phase 1 (0s~120s). 24 signals are transmitted, with a time interval of 5s±0.2s between adjacent signals; the first signal is emitted from the position indicator. Transmission will begin within 5 seconds of activation.

b) Phase 2 (120s~300s), a total of 18 signals are transmitted, with a time interval of 10s±0.2s between adjacent signals.

c) In stage 3 (after 300s), the time intervals between adjacent signals are evenly distributed between 27s and 30s, and the values are random. 5.1.2.2.3 For stand-alone ELT(DT) containing 3LD in PDF-2, the repetition period should meet the following requirements.

a) Phase 1 (0s~120s). 24 signals are transmitted, with a time interval of 5s±0.2s between adjacent signals. The first signal is transmitted via the position indicator. Transmission begins within 5 seconds, and starting from the second signal, 3LD is transmitted once every 4 signals.

b) Phase 2 (120s~300s). 18 signals are transmitted, with a time interval of 10s±0.2s between adjacent signals; the 25th signal is emitted. After 5s ± 0.5s, the first signal containing 3LD is transmitted, and thereafter a signal containing 3LD is transmitted every 6 times, plus... The 3LD signal was transmitted a total of 21 times.

c) Phase 3 (300s later). The 46th signal is transmitted once every 28.5s on average after the start of the 45th signal, with the time interval between adjacent signals... The values are uniformly distributed between 27.0s and 30.0s, and are randomly selected; after the 61st signal ends and every 30 subsequent signals, the values are determined by the previous signal. Within 15s ± 0.5s after the signal begins, a signal containing 3LD is sent once. 5.1.2.2.4 The repetition cycle of the impact-type ELT (DT) should meet the following requirements.

a) If the ELT(DT) has a crash detection function, and it is activated or reactivated within 5 seconds after a crash, then the ELT(DT) is considered to be activated. It is active and will continue to transmit signals at least 95 times (approximately 30 minutes).

b) The average signal transmission time interval (TR) after the 95th transmission is 120s, and it is evenly distributed between 115s and 125s.

c) For the next 18 consecutive signals, the standard deviation of TR is greater than 2.5s, the minimum TR value is 115.0s~115.2s, and the maximum TR value is... 124.8s~125.0s.

d) For ELT(DT) containing 3LD in PDF-2, no more 3LD information is transmitted after the 95th signal.

e) If the ELT(DT) has been running in flight for more than 370 minutes and has not yet switched to "post-crash" mode or been deactivated, continue pressing the button. Transmit signals according to the rules established 370 minutes ago (update GNSS position information before each signal transmission) until any of the following conditions are met. occur. 1) ELT(DT) is disabled; 2) Upon receiving a subsequent "crash" signal, switch to "post-crash" mode; 3) Battery depleted; 4) Achieve the shortest continuous running time. 5.1.2.2.5 The repetition period of the combined ELT(DT) transmission signal shall meet the following requirements.

a) When activated as ELT(DT), it conforms to the provisions of 5.1.2.2.2 or 5.1.2.2.3;

5.1.3 Modulator and 406MHz Transmitter

5.1.3.1 Transmission Frequency The carrier frequency of the position indicator should be set within ±1 kHz of the corresponding channel center frequency in accordance with the requirements of C/ST.012, and should not exceed 5 years. The range is -5kHz to 5kHz. This excludes position indicators operating on the following channels.

a) 406.025MHz channel, carrier frequency set at 406.025MHz±2kHz, not exceeding -5kHz to 5kHz within 5 years. The range of variation;

b) 406.028MHz channel, carrier frequency set at 406.028MHz±1kHz, not exceeding -5kHz to 2kHz within 5 years. The range of variation.

5.1.3.2 Transmission frequency stability 5.1.3.2.1 Short-term stability The short-term variation of the transmission frequency within 100ms should not exceed 2×10-9. 5.1.3.2.2 Medium-term stability Mid-term stability of the transmission frequency is determined by the average slope of the frequency versus time over 15 minutes, and the residual frequency change of the average slope. It should be meaningful and should meet the following requirements.

a) The average slope change does not exceed 1×10^-9 within 1 minute (under stable temperature conditions), and does not exceed 2×10^-9 within 1 minute. (Under variable temperature conditions of ±5°C/h);

b) The residual frequency change does not exceed 3×10-9 within 1 minute. Mid-term stability of the transmit frequency does not apply to ELT(DT).

5.1.3.3 Transmitter Power Output For position indicators other than ELT(DT), the transmitter output power measured under a 50Omega load should be in the range of 35dBm to 39dBm. Within the operating temperature range specified in 5.3.1.1, the transmitter shall maintain this power output range for at least 24 hours of operation. The rise time of the power output measured between 10% and 90% power points should be less than 5ms. For ELT(DT), the transmitter output power measured under a 50Omega load should be in the range of 36dBm to 39dBm. The output should be maintained within a minimum continuous operating time of 370 minutes.

5.1.3.4 Antenna Characteristics For azimuth angles of 0° to 360° and elevation angles of 5° to 60°, the antenna should meet the following characteristics.

a) The beam pattern is hemispherical.

b) The polarization mode is RHCP or linear polarization.

c) The gain must meet the following requirements. 1) Within 90% of the azimuth and elevation angles, the position markers other than ELT(DT) are -3dBi to 4dBi; 2) Within the 90% range of azimuth and elevation angles, ELT(DT) is -2dBi to 6dBi.

d) VSWR not exceeding 1.5.1.

5.1.3.5 In-band stray emission When measured at a resolution bandwidth of 100Hz, the in-band spurious emissions should not exceed the level specified by the signal mask in Figure 1. Figure

5.2 Digital Information Content

5.2.1 Information Structure The digital information transmitted by the position indicator is of two types.

a) 112-bit short format information, the information structure is shown in Figure 5a);

b) 144-bit long format information, the information structure is shown in Figure 5b).

a) Short format information

b) Long format information

5.2.2 System Bits The first 24 bits are system bits, of which bits 1 to 15 are used for bit synchronization and bits 16 to 24 are used for frame synchronization.

5.2.3 Data Bits Bits 25 through 85 are PDF-1.

a) The 25th bit is the format identifier, where "0" indicates short format information and "1" indicates long format information.

b) The 26th bit is the protocol identifier, where "0" indicates a standard location protocol or a national location protocol, and "1" indicates a user protocol or user location protocol. Set the agreement.

c) Bits 27 to 36 are the country code.

d) Bits 37 to 85 represent identification data, and when a user protocol or user location protocol is used, bits 37 to 39 are... Protocol code; when using standard location protocol, national location protocol, RLS location protocol, or ELT(DT) location protocol, bit 37~ The 40th bit is the protocol code. The specific protocol coding specifications should comply with the provisions of Appendix A.

5.2.4 First Error Correction Code Field Bits 86 to 106 are BCH-1, see Appendix B.

5.2.5 Second Error Correction Code Field Bits 133 to 144 of the long format information are BCH-2.

5.2.6 Encoding

5.2.6.1 Short format message encoding shall meet the following requirements.

a) Bit synchronization field, bits 1 to 15;

b) Frame synchronization field, bits 16 to 24;

c) PDF-1 field, bits 25 to 85;

d) BCH-1 field, bits 86 to 106;

e) Non-data protection fields, bits 107 to 112.

5.2.6.2 Long format message encoding shall meet the following requirements.

a) Bit synchronization field, bits 1 to 15;

b) Frame synchronization field, bits 16 to 24;

c) PDF-1 field, bits 25 to 85;

d) BCH-1 field, bits 86 to 106;

e) PDF-2 field, bits 107 to 132;

f) BCH-2 field, bits 133 to 144.

5.2.6.3 Position markers should adopt different encoding schemes according to different user usage types. User protocol encoding should conform to the provisions of A.1, and the position... Protocol encoding should conform to the provisions of A.2 to A.4.

5.3.1 Environmental Requirements

5.3.1.1 Operating Temperature The operating temperature of the position indicator should be permanently marked on the outside of the machine body. The operating temperature range is divided into the following three levels.

a) Level 0.-55°C to 70°C;

b) Level 1.-40°C to 55°C;

c) Level 2.-20°C to 55°C.

5.3.1.2 Temperature gradient The device should function normally when the fully encapsulated position marker is affected by the temperature gradient change shown in Figure 6.

5.3.1.3 Thermal shock Within the specified operating temperature range, activate the position indicator and simultaneously apply a 30°C thermal shock. After 15 minutes, take a measurement; the position indicator should meet the following requirements. The system requirements specified in

5.1 include that the average slope measurement of the mid-term frequency stability should not exceed 2 × 10^-9. For ELT(DT), all system requirements specified in

5.1 except for mid-term frequency stability should be met. Within the specified operating temperature range... Within the specified range, the ELT(DT) is activated while being subjected to a 50°C thermal shock. Measurements are taken from the first transfer, and subsequently the ELT(DT) should continuously meet at least the following conditions. The system requires 2 hours.

5.3.2 Operational Requirements

5.3.2.1 Continuous running time 5.3.2.1.1 Within the specified operating temperature range, the minimum duration of continuous operation of the position indicator at any temperature shall be at least 24 hours. 5.3.2.1.2 The batteries provided with EPIRB shall comply with the requirements of IMO MSC.471(101) and be able to operate continuously for at least 48 hours. 5.3.2.1.3 Within the specified operating temperature range, the minimum continuous operating time of the ELT(DT) at any temperature shall be 370 min. 5.3.2.1.4 Within the specified operating temperature range, the minimum continuous operating time of the impact ELT (DT) should be 24 hours. If the impact ELT... If the (DT) system continues to operate after 370 minutes and no crash is detected, the 24-hour operating time is not applicable because the operating time in ELT(DT) mode has been extended. The minimum continuous operating time requirement. 5.3.2.1.5 Within the specified operating temperature range, the minimum continuous operating time of the combined ELT (DT) should be 1810 min. If the combined... If ELT(DT) continues to operate after 370 minutes and no crash is detected, it is not applicable because the operating time in ELT(DT) mode has been extended. Minimum continuous working time. 1810 min.

5.3.2.2 Auxiliary Radio Positioning Device If the position beacon is equipped with an auxiliary radio positioning device, it should provide assistance through built-in or external auxiliary radio positioning devices on other frequencies. Location data. The operation or malfunction of the auxiliary positioning device should not affect or degrade the performance of the position beacon.

5.3.2.3 Self-test mode 5.3.2.3.1 The position marker should include a self-test mode, and the self-test message should always provide the position marker's 15HEXID. 5.3.2.3.2 In self-test mode, the digital information should include the frame synchronization code (011010000) to prevent the self-test signal from being received by satellite equipment. deal with. 5.3.2.3.3 The self-test mode should be activated by a separate switch position. The self-test function should perform internal checks and provide clear instructions. 5.3.2.3.4 The design of the position indicator should ensure that the self-test mode is automatically terminated immediately after the self-test cycle is completed and the self-test result is indicated. 5.3.2.3.5 When operating in position beacon self-test mode, it should not transmit 406MHz signals or other radio positioning signals (if applicable), nor... This should interfere with the normal operation of the position indicator. 5.3.2.3.6 A complete self-test message transmission should be limited to a single burst and meet the maximum transmission duration. for the short format, it should be 440ms ± 4.4ms, the long format should be 520ms ± 5.2ms. 5.3.2.3.7 ELT(DT) should transmit a long format self-test message. 5.3.2.3.8 For ELT(DT) containing 3LD, a long self-test message containing the rotation field and 3LD should be sent in PDF-2. 5.3.2.3.9 For position markers using location protocol encoding, the encoded position data field of the self-test message should be the default value. 5.3.2.3.10 Position beacons using location protocol encoding shall meet the following requirements in GNSS self-test mode.

5.3.2.4 Location Data 5.3.2.4.1 Basic Requirements 5.3.2.4.1.1 The position data of the beacon should be obtained from its built-in or external GNSS receiver and encoded into its information code. 5.3.2.4.1.2 The position data of the position markers shall be encoded into their information codes according to methods A.2 to A.4.The encoded position data shall be subject to BCH. Protect. 5.3.2.4.1.3 The location data of the position markers shall be coded in accordance with the geodetic coordinate system recognized by C/S. 5.3.2.4.2 Built-in GNSS performance 5.3.2.4.2.1 The built-in GNSS should have global operation capability. 5.3.2.4.2.2 The built-in GNSS should have a self-checking function to ensure that erroneous position data is not encoded into the position beacon digital information. 5.3.2.4.2.3 The built-in GNSS beacon should provide valid position data within 10 minutes of activation. After obtaining valid position data... Previously, the location data was set to the default value. 5.3.2.4.2.4 Each time the position beacon is activated, the built-in GNSS receiver should be forced to cold start, clearing the time- or location-related buffers. data. 5.3.2.4.3 Built-in GNSS timing 5.3.2.4.3.1 The built-in GNSS should be activated immediately after the position beacon is activated. 5.3.2.4.3.2 The built-in GNSS should attempt to acquire initial positioning after the beacon is activated, and continue for at least 10 minutes. 5.3.2.4.3.3 After the initial positioning attempt is completed, the time interval between subsequent initial positioning or positioning updates should be greater than 265 seconds and should not exceed [a certain value]. 15 minutes. 5.3.2.4.3.4 After obtaining the initial location or updating the location, it should be encoded into the next piece of position marker digital information to be transmitted. 5.3.2.4.3.5 If the updated position is not obtained before transmitting the next position indicator number, the previous position data should be transmitted; if 4h± If the position is not updated after 5 minutes, the encoding position should be the default value. 5.3.2.4.3.6 GNSS should be enabled for at least 90 seconds each time an attempt is made to acquire the initial position or update the position; if the position is acquired earlier... If location data is to be acquired after 10 seconds, the sleep mode should be entered after 10 seconds. If location data is to be acquired after 80 seconds, the sleep time should be shortened by 10 seconds depending on the actual situation. The preparation time is long, but the total cumulative operating time of the navigation device should still be ensured to be at least 90 seconds. 5.3.2.4.4 External GNSS Access 5.3.2.4.4.1 Position beacons connected to external GNSS shall provide an interface compliant with IEC 61162-1. 5.3.2.4.4.2 External GNSS should have a self-checking function to ensure that erroneous position data is not encoded into the position beacon digital information. 5.3.2.4.4.3 If the beacon has already acquired position data from an external GNSS, a line containing the coded position and location should be generated within 1 minute of activation. BCH digital information. 5.3.2.4.4.4 If the beacon is designed to acquire external GNSS location data before activation, the time interval for providing location data should not exceed [a specified value]. After 20 minutes (EPIRB and PLB) or 1 minute (ELT). 5.3.2.4.5 ELT(DT) equipped with GNSS 5.3.2.4.5.1 The ELT(DT) shall be equipped with a built-in GNSS and provide an external GNSS interface. The ELT(DT) shall use the ELT(DT) bit. The protocol is used for encoding. The BCH should always match the message content. 5.3.2.4.5.2 The initial ELT(DT) transmission should be completed within 5 seconds after the position beacon is activated. If there is no position information after activation, the transmission before activation should be completed. The last acquired location data and acquisition time (accurate to 5 seconds). To facilitate providing location data before activation, ELT(DT) should acquire data every 2 seconds. Location data is stored in memory.