Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
GJB 1198 consists of the following eight parts under the general title Telemetry tracking command and data handling for spacecraft:
——Part 1: PCM telecommand;
——Part 2: PCM telemetry;
——Part 3: Telemetry channel coding;
——Part 4: Ranging;
——Part 5: Radio frequency and modulation;
——Part 6: Packet telemetry;
——Part 7: Packet telecommand;
——Part 8: Onboard data handling interface.
This part is Part 8 of GJB 1198.
This part replaces GJB 1198.8-1991 Telemetry tracking command and data handling for satellite: Onboard data handling interface.
Clauses 1 to 6 of this part are prepared with reference to Part II of the European Space Agency standard TTC-B-01 Space Craft Data Handling Interface Standards (1979), and the technical indexes are classified into two levels: A and B, of which Level B index is lower; the two switch commands of the previous standard are combined into one; the number transmitted by serial input and output channels is longer and more flexible; Clause 1 "General" and Clause 3 "Data bus interface standard" of this standard are not adopted. The data bus interface, i.e., Clause 7 of this part is prepared according to GJB 289A-1997 Digital time division command/response multiplex data bus, which is identical to the US military standard MIL-STD-1553B Aircraft Internal Time Division Command/Response Multiplex Data Bus (1980); all these differences are based on the actual situation of spacecraft development in China.
The following main changes have been made in this part with respect to the previous edition:
a) "Serial 8Nbit digital channel" and "8Nbit serial loading command" only limit N to be a positive integer to meet the requirements of spacecraft for digital quantity transmission;
b) The contents of serial data bus interface are added, and the relevant contents of GJB 289A-1997 Digital time division command/response multiplex data bus are adopted; besides GJB 289A-1997, the content of simplified serial data bus is added.
This part was proposed by China Aerospace Science and Technology Corporation.
This part is under the jurisdiction of China Aerospace Standardization Institute.
This part was firstly issued in April 1991, and firstly revised this time.
Telemetry tracking command and data handling for spacecraft
Part 8: Onboard data handling interface
1 Scope
This part specifies the general provisions of interface of spacecraft data handling system (hereinafter referred to as data handling system), as well as telemetry channel interface, telecommand channel interface and serial data bus interface.
This part is applicable to spacecraft data handling system and users who have interface with data handling system.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this part. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest editions apply to this part.
GJB 289A-1997 Digital time division command/response multiplex data bus
GJB 727A-1998 Terms and acronyms of space tracking telemetry and command system
3 Terms and definitions
For the purposes of this part, the terms and definitions established in GJB 727A-1998 and the following ones apply.
3.1
central terminal unit (CTU)
central control equipment of data handling system, which collects data acquired from remote unit, data transmitted through serial data bus and data generated by computer software; processes, stores and sends downlink telemetry data to telemetry transmitter (transponder) of spacecraft; processes, stores and distributes telecommands and data from earth station or other spacecraft, as well as control commands and data generated by spacecraft; generates spacecraft clock, implements the handling of spacecraft computer, and realizes the handling of serial data bus and spacecraft data.
3.2
remote terminal unit (RTU)
equipment configured at different parts of spacecraft to collect telemetry data and distribute commands and data, which can also complete closed-loop autonomous control
3.3
remote bus interface (RBI)
serial data bus interface boards configured in other subsystems, equipment and scientific instruments which are used to realize data exchange between CTU and these subsystems, equipment and scientific instruments via serial data bus
3.4
telecommand unit (TCU)
equipment for receiving uplink telecommand information (including data and commands) from spacecraft telecommand receiver (transponder). These messages are processed to generate direct ON/OFF command for users or sent to CTU in the form of serial loading commands.
3.5
command decoder unit (CDU)
equipment for decoding uplink telecommand information to generate direct ON/OFF command
3.6
direct ON/OFF command
ON/OFF command transmitted to the spacecraft in the form of command through the earth station or other spacecraft, and directly decoded by TCU and CDU
3.7
routed ON/OFF command
ON/OFF command transmitted to the spacecraft in the form of data injection through the earth station or other spacecraft, and output by RTU after being processed by CTU, which can be output in real time or with delay
3.8
on-board ON/OFF command
command generated by spacecraft according to pre-given algorithms and criteria during spacecraft operation
4 General provisions
4.1 General
Onboard data handling interface shall ensure electrical matching and fault isolation between interfaces.
4.2 Types of interfaces
4.2.1 Telemetry channel is the interface for collecting user data by data handling system. Because of the different types of data collected, the telemetry channel can adopt single or several transmission lines. It is also classified into the following categories:
a) Analog channel: for collecting analog signals input by single or double ends;
b) Digital channel: for collecting 8Nbit serial digital signal (N is a positive integer);
c) Bi-level digital channel: for collecting 1-bit status data, and compile 8-bit status data into a group (one telemetry word);
d) Timing channel: for acquiring the time when a single event occurs.
4.2.2 The telecommand channel is the interface for transmitting the commands and data of the data handling system to the user. Because of the different types of commands, the telecommand channel can also adopt one or more transmission lines. It is classified into the following categories:
a) ON/OFF command channel: it is provided to users in the form of pulses with a certain width, which is used to drive loads with higher power;
b) Serial loading command channel: for transmitting 8Nbit data words to users (N is a positive integer).
4.2.3 The serial data bus is used to realize the information transmission among modules of the data handling system and between the data handling system and spacecraft subsystems, equipment and scientific instruments through the remote bus interface. PCM data is transmitted based on the principle of time division multiplexing.
4.3 Agreement of signal and level
4.3.1 Serial digital signal (NRZ-L)
This kind of signal appears in telemetry digital channel interface, and command channel interface loaded with telecommand serial. For telemetry channel, serial digital signal is the input of data handling system; while for telecommand channel, serial digital signal (data word) is the output of data handling system. The logic "1" of digital signal is represented by positive voltage or switch OFF, and the logic "0" of digital signal is represented by zero voltage or switch ON.
4.3.2 Sampling signal and address signal
This kind of signal is used for the transmission of serial digital signals. When the number of user addresses in specific subsystem of spacecraft is small, the sampling signal is the gated signal directly provided by the RTU to the user; when the number of user addresses in a specific subsystem is large (generally more than 8), address codes may be provided to users in the form of address signals, and then the subsystem completes address decoding by itself to generate gated signals of corresponding addresses.
The gated signal, whether directly provided by the sampling signal or generated by decoding the address signal, is a switch closing signal. In the working state (i.e. gated state), the switch is ON; in the non working state, the switch is OFF. When the circuit is designed to ensure the working state, the user input end is at zero level.
4.3.3 Bi-level digital signal
Bi-level digital signals have no non-working state, i.e. "static state".
This kind of signal is the data input of telemetry bi-level digital channel. Represented by two logic states, positive voltage corresponds to logic “1” and zero voltage corresponds to logic “0”.
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 General provisions 5 Telemetry channel interface 6 Telecommand channel interface 7 Serial data bus interface (recommendatory)
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
GJB 1198 consists of the following eight parts under the general title Telemetry tracking command and data handling for spacecraft:
——Part 1: PCM telecommand;
——Part 2: PCM telemetry;
——Part 3: Telemetry channel coding;
——Part 4: Ranging;
——Part 5: Radio frequency and modulation;
——Part 6: Packet telemetry;
——Part 7: Packet telecommand;
——Part 8: Onboard data handling interface.
This part is Part 8 of GJB 1198.
This part replaces GJB 1198.8-1991 Telemetry tracking command and data handling for satellite: Onboard data handling interface.
Clauses 1 to 6 of this part are prepared with reference to Part II of the European Space Agency standard TTC-B-01 Space Craft Data Handling Interface Standards (1979), and the technical indexes are classified into two levels: A and B, of which Level B index is lower; the two switch commands of the previous standard are combined into one; the number transmitted by serial input and output channels is longer and more flexible; Clause 1 "General" and Clause 3 "Data bus interface standard" of this standard are not adopted. The data bus interface, i.e., Clause 7 of this part is prepared according to GJB 289A-1997 Digital time division command/response multiplex data bus, which is identical to the US military standard MIL-STD-1553B Aircraft Internal Time Division Command/Response Multiplex Data Bus (1980); all these differences are based on the actual situation of spacecraft development in China.
The following main changes have been made in this part with respect to the previous edition:
a) "Serial 8Nbit digital channel" and "8Nbit serial loading command" only limit N to be a positive integer to meet the requirements of spacecraft for digital quantity transmission;
b) The contents of serial data bus interface are added, and the relevant contents of GJB 289A-1997 Digital time division command/response multiplex data bus are adopted; besides GJB 289A-1997, the content of simplified serial data bus is added.
This part was proposed by China Aerospace Science and Technology Corporation.
This part is under the jurisdiction of China Aerospace Standardization Institute.
This part was firstly issued in April 1991, and firstly revised this time.
Telemetry tracking command and data handling for spacecraft
Part 8: Onboard data handling interface
1 Scope
This part specifies the general provisions of interface of spacecraft data handling system (hereinafter referred to as data handling system), as well as telemetry channel interface, telecommand channel interface and serial data bus interface.
This part is applicable to spacecraft data handling system and users who have interface with data handling system.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this part. However, parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest editions apply to this part.
GJB 289A-1997 Digital time division command/response multiplex data bus
GJB 727A-1998 Terms and acronyms of space tracking telemetry and command system
3 Terms and definitions
For the purposes of this part, the terms and definitions established in GJB 727A-1998 and the following ones apply.
3.1
central terminal unit (CTU)
central control equipment of data handling system, which collects data acquired from remote unit, data transmitted through serial data bus and data generated by computer software; processes, stores and sends downlink telemetry data to telemetry transmitter (transponder) of spacecraft; processes, stores and distributes telecommands and data from earth station or other spacecraft, as well as control commands and data generated by spacecraft; generates spacecraft clock, implements the handling of spacecraft computer, and realizes the handling of serial data bus and spacecraft data.
3.2
remote terminal unit (RTU)
equipment configured at different parts of spacecraft to collect telemetry data and distribute commands and data, which can also complete closed-loop autonomous control
3.3
remote bus interface (RBI)
serial data bus interface boards configured in other subsystems, equipment and scientific instruments which are used to realize data exchange between CTU and these subsystems, equipment and scientific instruments via serial data bus
3.4
telecommand unit (TCU)
equipment for receiving uplink telecommand information (including data and commands) from spacecraft telecommand receiver (transponder). These messages are processed to generate direct ON/OFF command for users or sent to CTU in the form of serial loading commands.
3.5
command decoder unit (CDU)
equipment for decoding uplink telecommand information to generate direct ON/OFF command
3.6
direct ON/OFF command
ON/OFF command transmitted to the spacecraft in the form of command through the earth station or other spacecraft, and directly decoded by TCU and CDU
3.7
routed ON/OFF command
ON/OFF command transmitted to the spacecraft in the form of data injection through the earth station or other spacecraft, and output by RTU after being processed by CTU, which can be output in real time or with delay
3.8
on-board ON/OFF command
command generated by spacecraft according to pre-given algorithms and criteria during spacecraft operation
4 General provisions
4.1 General
Onboard data handling interface shall ensure electrical matching and fault isolation between interfaces.
4.2 Types of interfaces
4.2.1 Telemetry channel is the interface for collecting user data by data handling system. Because of the different types of data collected, the telemetry channel can adopt single or several transmission lines. It is also classified into the following categories:
a) Analog channel: for collecting analog signals input by single or double ends;
b) Digital channel: for collecting 8Nbit serial digital signal (N is a positive integer);
c) Bi-level digital channel: for collecting 1-bit status data, and compile 8-bit status data into a group (one telemetry word);
d) Timing channel: for acquiring the time when a single event occurs.
4.2.2 The telecommand channel is the interface for transmitting the commands and data of the data handling system to the user. Because of the different types of commands, the telecommand channel can also adopt one or more transmission lines. It is classified into the following categories:
a) ON/OFF command channel: it is provided to users in the form of pulses with a certain width, which is used to drive loads with higher power;
b) Serial loading command channel: for transmitting 8Nbit data words to users (N is a positive integer).
4.2.3 The serial data bus is used to realize the information transmission among modules of the data handling system and between the data handling system and spacecraft subsystems, equipment and scientific instruments through the remote bus interface. PCM data is transmitted based on the principle of time division multiplexing.
4.3 Agreement of signal and level
4.3.1 Serial digital signal (NRZ-L)
This kind of signal appears in telemetry digital channel interface, and command channel interface loaded with telecommand serial. For telemetry channel, serial digital signal is the input of data handling system; while for telecommand channel, serial digital signal (data word) is the output of data handling system. The logic "1" of digital signal is represented by positive voltage or switch OFF, and the logic "0" of digital signal is represented by zero voltage or switch ON.
4.3.2 Sampling signal and address signal
This kind of signal is used for the transmission of serial digital signals. When the number of user addresses in specific subsystem of spacecraft is small, the sampling signal is the gated signal directly provided by the RTU to the user; when the number of user addresses in a specific subsystem is large (generally more than 8), address codes may be provided to users in the form of address signals, and then the subsystem completes address decoding by itself to generate gated signals of corresponding addresses.
The gated signal, whether directly provided by the sampling signal or generated by decoding the address signal, is a switch closing signal. In the working state (i.e. gated state), the switch is ON; in the non working state, the switch is OFF. When the circuit is designed to ensure the working state, the user input end is at zero level.
4.3.3 Bi-level digital signal
Bi-level digital signals have no non-working state, i.e. "static state".
This kind of signal is the data input of telemetry bi-level digital channel. Represented by two logic states, positive voltage corresponds to logic “1” and zero voltage corresponds to logic “0”.
Contents of GJB 1198.8A-2004
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 General provisions
5 Telemetry channel interface
6 Telecommand channel interface
7 Serial data bus interface (recommendatory)
