1. No category

Changing the economics of space
Procyon is a cost-effective star tracker for
missions with medium-accuracy attitude
determination requirements. The camera head
unit (CHU) is supplied by Terma and is based
on a low-cost-and-mass STR active pixel
sensor (LCMS APS) technology. The data
processing unit (DPU) is a miniaturized variant
of Surrey’s onboard computer, the OBC750.
The LCMS APS sensor offers increased
capability and flexibility in a cost-effective
design. The star tracker outputs attitude in
the form of a quaternion with associated
timestamp. With suitable filtering, the Procyon
Star Tracker can also be used to provide
excellent rate estimates.
Procyon is flying as a complete unit on
Surrey’s TechDemoSat-1 mission, while the
DPU will gain heritage as part of Surrey’s
Rigel-L Star Tracker on a further four missions.
Features
•• Fully autonomous
•• Lost-in-space capability
•• Modular design
•• A single DPU can support up to two CHUs
Benefits
Heritage (Procyon)
•• Flight-proven star extraction and attitude
determination algorithms
•• Variant on TechDemoSat-1 (2014)
•• Low cost
•• Formosat-7 (2016)
•• 12 months typical delivery
Heritage (Additional CHU)
•• LCMS APS sensor flown on UK-DMC-2 and
NigeriaSat-X
Heritage (Additional DPU)
•• Derived from OBC750, NigeriaSat-2 (2011)
•• KazEOSat-2 (2014)
•• DMC3 constellaton (2015)
•• NovaSAR-S (2015)
•• 7+ years design life
•• High performance
Subsystem
••Procyon Star Tracker
Subsystem
••Procyon Star Tracker
Physical Characteristics
Performance Properties
DPU: 155 x 210 x 56 mm
Dimensions
Relative Accuracy
30º baffle CHU: Ø125 x 165
16–50 V unregulated
Power
X/Y < 5 arcsec (1σ)
Z < 30 arcsec (1σ)
Bias
X/Y/Z < 5 arcsec (1σ)
Maximum Rate/
Acceleration
1 deg/sec
0.3 deg/s2
Attitude Acquisition Time
8 s from power on
Update Rate
1 Hz to 4 Hz
Sun/Earth Exclusion Angle
30 degrees
Moon Exclusion Angle
Robust to Moon in field of
view
TTC Interface
CAN-SU or optional
Procyon: 6.5 W
DPU: 1.2 kg
Mass
30º baffle CHU: 0.55
Radiation
5 kRad (Si)
Random Vibration
DPU:15 grms in all axes
CHU:17 grms in Z axis
22 grms in X and Y axes
Lifetime
7.5 years LEO orbit (<800 km)
Temperature
-30 °C to +15 °C performance
-20 °C to +50 °C performance
-30 °C to +60 °C non-operating
(RS422 and spacewire)
Typical Use
28 V
PPS
LVDS
DPU-0
CHU-0
DPU-1
CHU-1
RS 422
LVDS
PPS
28V
Data processing unit (DPU)
Product specification subject to change without notification
The small satellite revolution started 30 years ago with Surrey Satellite Technology—the world’s premier provider of operational and
commercial satellite programs with over 40 satellites launched successfully and 240 years of on-orbit experience gained.
From its Englewood, Colorado, facilities, Surrey supplies complete in-house design, manufacture, launch, and operation of small
satellites, to include remote sensing, navigation, and communications payloads, avionics suites and subsystems, ground infrastructure,
and training and consulting services.
Surrey Satellite Technology US LLC
345 Inverness Drive South, Suite 100 | Englewood, CO 80112 | 303.790.0653 | www.surreysatellite.com
Surrey US is AS 9100:2009-certified | GSA Contract Holder | Shop Surrey online at www.surreysatellite.com/shop
March 2015
Dual cold redundant chain