System of Guidance Sensors (SDG)

Space Research Institute of the Russian Academy of Sciences is involved in the creation of the International space Astrophysical Observatory (WCO-UV), designed for space exploration in ultraviolet range with high angular resolution.
The observatory is based on a "Spektr-UF" s/c with a T-170M telescope onboard.
In order to solve the observatory tasks the telescope should be pointed to the observed object with high accuracy and hold in the specified position for a sufficiently long time intervals.
To do this, it is planned to use in the telescope the System of guidance sensors (SDG) being developed at the Optico-physical department.
Guidance sensors are located in the telescope's focal area and are capable to observe the stars with a magnitude of 15-17 through its optical system.
Data from the guidance sensors is transmitted to the data processing unit, where it is processed to determine the telescope attitude in inertial space

Arrangement of equipment in the telescope's instrumentation compartment

Prototype of the guidance sensor

Guidance sensor engineering model

Main characteristics of SDG
Number of guidance sensors 3
Power consumption, W:
- with one operating guidance sensor
- with two operating guidance sensors
- with three operating guidance sensors

less than 20
less than 30
less than 40
Cable length between Data processing unit and guidance sensor, m 4
Probability of failure-free operation more than 0,95
Lifetime, years 10
Rms of determining the deflection angle
- around the axis perpendicular to
the line of sight, arcsec
- around the line of sight

Data updatement frequency, Hz 0,5

Guidance sensor characteristics
CCD-matrix "Sfera-1000"
Number of CCD pixels(pixel size, mkm) 1024х1024(16х16)
Mass, kg 0,7
Dimensions, mm 152х112,5х45,8
Operating temperature range, °С +15..+25
Ultimate star magnitude +17
Field of view, arcmin 3х3
ADC capacity, bit 12
Gain 5..15

Characteristics of data processing unit
Mass, kg 4,3
Dimensions, mm 230х178,5х154
Operating temperature range, °С -20..+40
Redundancy cold redundancy
Output interface MPI(GOST Р 52070-2003)