Experiment Design

Setup

The experiment consists of three units. Supikoira flight computer 2 (SFC2), Inertial Measurement Unit 2 (IMU2) and the Experiment Digital Camera (EDC). The SFC2 will record inertial measurement data from IMU2 and images from the EDC. IMU2 data will be recorded to onboard memory and the images will be recorded on external SD memory card.

Communication

SFC2 and IMU2 will be communicating over MIL-STD-1553 Bus. SFC2 and EDC will be communicating over Ethernet and a couple of digital IO lines. SFC2 will be also communicating to the ground station via radio uplink and downlink provided by the REXUS rocket. The REXUS communication is going over RS-422 serial link.

Enclosures

There will be separate enclosure for each unit. Only the IMU2 enclosure will be pressurised.

  • SFC2 enclosure: A flat box
  • IMU2 enclosure: A cylinder (pressurised)
  • EDC mount: Integrated to an umbilical mount
Software

Software consists of three distinct parts:

1. SFC2 software
  • Operating system: RTEMS
  • HW drivers (UART, Clock, Timer, RTC, SD/MMC, MIL-STD-1553, Ethernet)
  • Navigation software
  • Logging
  • MIL-STD-1553 bus controller
  • Camera control
  • Uplink/Downlink
  • HW drivers written in C, other software in Ada95
2. IMU software
  • Measures accelerations, angular velocities and sensor temperatures.
  • Does sensor error compensation.
  • Does integration of inertial measurements
  • MIL-STD-1553 remote terminal
  • Written in C
3. Ground software:
  • Flight visualization
  • Logging
  • Written in Python/C/Ada95

With the exception of MIL-STD-1553 driver, software is developed on Embedded Artists LPC2468 prototyping board, while waiting for the actual hardware to finish. Navigation algorithms are prototyped with Python / Numpy, before implementation in Ada95.

Electronics

Main components of SFC2:
CPU MCU (NXP LPC2468 ARM7) and DSP (TI TMS320C6722B)
RAM Dualport (Cypress CY7C025AV) and SDRAM (64MB)
Memory Onboard (4 x 16Mbit AT25DF321) and SD (4GB)
Bus CAN (LT1796), RS-422/485 (LT1785) and 1553 (Holt IC HI-6110)
RTC DS1338Z
Power PSU(LM2576HV + 2 x LT1963)
Components of IMU2:
CPU MCU (AT91SAM7A3 ARM7)
ADC ADS7656
Gyroscopes 3 x Silicon Sensing SiRRS01-07
Accelometers 3 x Colibrys MS8000
Bus 1553 (Holt IC HI-6110)
Power LM Series Switching and Linear Postregulation
Experiment Digital Camera (EDC):
Camera Dalsa Genie C1024, GigE Vision Camera
Optics f=8mm F:1.4-C, 2/3"