Optico-physical Department

Dynamic Test Equipment for Star Trackers Processing

The first modification of the Dynamic Test Equipment (DTE) was developed at the Optico-physical department in 2001. DTE is a set of hardware and software that allows to simulate on Earth light-optical conditions close to the working conditions of star trackers in space.
DTE has been designed to test the star trackers operation, debug their software and conduct ground tests.
DTE can be used for testing star trackers with a circular field of view <= 180 working over the star field, capable to register stars up to 7.5 magnitude in the wavelength range of 0.5 - 0.8 mm.
Thus, DTE is suitable for testing all versions of star trackers, developed at IKI RAN: BOKZ, BOKZ-M, BOKZ-MF, BOKZ-M60, BOKZ-M60/1000.

Dynamic test equipment includes:

• - monitor - star images simulator(SIS)
• - collimator
• - PC with a specialized software
• - dimming construction
• - optical rail
• - mechanical devices for accommodating instrument being tested and stand's elements

During testing star sensor the orientation parameters of the instrument coordinate system's axes are determined relative to the inertial coordinate system. The latter is simulated on a SIS computer screen using special software (program Sky Viewer), developed at the Optico-physical department.
DTE software provides for simulation of celestial sphere's sections radiation by reproducing energy and geometric characteristics of isolated stars and constellations. The spherical coordinates of stars on celestial sphere are recalculated to rectangular coordinates of stars projections onto SIS computer's screen,graphical image is formed and output to the computer screen. The repetition of this cycle with a specified frequency allows to implement the movement of celestial sphere's segment over the computer screen in a field of view of the fixed star tracker.
Various versions of star catalogues covering the whole celestial sphere are used for simulation.
In order to simulate the real space visual conditions the optical distancing of the celestial sphere image from an instrument to infinity is implemented by using a collimator located on the optical bench between SIS computer and the instrument, so that SIS monitor is in the tracker's focal plane.
In addition to star motion simulation DTE software provides for simulating the effect of space protons and particles of s/c own outer atmosphere, as well as illumination of the instrument's field of view.
At present all star tracker produced at IKI RAN are mandatory tested on the Dynamic test equipment.

SIS monitor
monitor type	LCD
resolution, pixel	1600 х 1200
pixel size, mm	0,255 х 0,255
Collimator focal length, mm	1010±10
Pixel angular size, arcsec	50
Field of view, grad	18 х 18
Range of simulated angular velocities, °/с	0…5
Possibility of operation remote control	TCP/IP (Ethernet, WiFi)
Frequency of celestial sphere images updatement, Hz	≤50
Dimensions, mm:	2000 х 700 х 700

DTE modifications were produced at IKI RAN on request of S.P. Korolev Rocket and Space Corporation Energia, JSC "Geofizika-Cosmos", JSC "Information Satellite Systems" Reshetnev Company, SaTReci (South Korea).