Time unified system

Time unified system
In space activities , Acquired by each TT & C war 、 The recorded measurement data and events must have a strict and unified time standard before they can be analyzed and processed , Only then has the use value . Time signals are also used to control program instruments , Complete the rocket 、 The ignition of the missile and the operation of the instrument according to the program .
Time unification system is a system that provides unified standard time signal and standard frequency signal for measurement and control system . There are many kinds of aerospace measurement and control equipment 、 Large number of 、 Wide distribution , If there is no uniform length of time , Can't complete the task at all . Launch take-off time (L)、 Ignition and shutdown time of rocket engines at all levels 、 Separation time 、 Data injection time 、 star ( ship ) Arrow separation time 、 The characteristic points of key events such as spacecraft man orbit time need the time system to provide accurate time . The time unified system is continuous and reliable 、 Stable operation is the prerequisite for the normal operation of the measurement and control system , Its performance directly affects the measurement accuracy and measurement system of aerospace measurement and control system . The composition of a typical time unified system is shown in the figure 1 Shown . It consists of time frequency reference and broadcasting system 、 Timing frequency correction signal receiving system 、 Local frequency standard 、 Time code generator 、 Distribution amplifier and user equipment .

The standardized time system equipment consists of timing and frequency correction unit 、 Frequency standard unit 、 Time code generation unit 、 Time code distinguishing unit 、 Monitoring computer, etc . The timing frequency correction unit generally has GPS And timing and frequency correction means of long and short wave timing system ; The frequency standard unit consists of rubidium atomic frequency standard and general quartz frequency standard, which is a local redundant frequency standard ; The time code generation unit passes 3 More than one redundant module forms a standard format B Time code , It is distributed and transmitted to nearby user equipment through time code differentiation unit ; The monitoring microcomputer visually displays the parameters of each unit 、 state , Report the equipment operation to the superior network management .
Time difference measurement equipment has time difference standardization 、 Delay correction 、 Leap second 、 Leap year 、 Set the time 、 Fault alarm and other functions , High reliability and stability , Distributed in large-scale measurement and control stations , Provide unified standard time-frequency signal format for measurement and control equipment .
The same system at the same time 、 Role in aerospace experiments ：
1. Mark missile 、 The moment of an important event in a space experiment
2. Unified missile 、 Time and frequency of space measurement system
3. Provide protection against missiles 、 The precise time required for spacecraft flight control
Requirements for key technical indicators of time unified system
missile 、 Aerospace experiments are carried out according to the needs of different experimental tasks , Different requirements are put forward for the time unified system . Generally speaking , Missile measurement has the highest requirements for time unified system .
Key technical index requirements
1. Time synchronization error , The relative time synchronization error plays a major role in the measurement error .
2. Frequency accuracy and frequency deviation .
3. Frequency stability , It is the speed measuring equipment that requires high frequency stability , Because the speed measuring equipment measures the Doppler frequency . Frequency stability is to characterize the size of standard frequency signal noise .
4. Sampling signal period jitter , The measuring equipment is on the missile 、 When measuring the trajectory of spacecraft , Time system equipment is required to provide time signals of various sampling rates .