Overview

Avionics literally means aviation electronics. In essence it comprises all electronic systems designed for use on an nearspacecraft. At a basic level this comprises navigation, communications (see Telemetry for more information),  sensors, flight control, power systems and management of these systems (see Software for more information). It also comprises multiple sub-systems that are fitted to nearspacecraft to meet individual roles.

Flight computer

The nearspacecraft avionics and operation is controlled with a low-power CPU board providing memory, non-volatile storage interface and sub-system bus interfaces.

CPU used in flight computer is a VIA C3 Samuel-2 clocked at 533Mhz. The CPU board has 512 MB of memory, an interface for flash based non-volatile storage device and two USB (Universal Serial Bus) controllers for sub-system communication (navigation, telemetry, flight control, payload).

Flight  computer runs customized Linux kernel and a Java language runtime for avionics software. (see Software for more information)

Flight control

The Arctic Nearspace Project uses controller board sponsored by EasyDAQ to control various sub-systems of the nearspacecraft:

• Emergency Cut-Off Device (ECD)

• Lights

• Audible ground locator beacon

• Power distribution

Most critical sub-systems controlled with the EasyDAQ board will have backup wiring and control relays.

EasyDAQ USB8PR relay board

The EasyDAQ boards can be easily programmed and controlled with most modern operating systems and programming languages that have support for USB/Serial-port communication. For example, we use Linux with Java runtime to control the EasyDAQ board in our nearspacecraft  (see Software for more information).

Navigation

The Arctic Nearspace Project nearspacecraft will use high channel count GPS (Global Positioning System) receiver with WAAS/EGNOS support for enhanced reliability and accuracy. The Global Positioning System is the only fully-functional satellite based navigation system. More than two dozen GPS satellites orbit the Earth, transmitting radio signals which allow GPS receivers to determine their location, altitude, speed and direction.

The EGNOS (European Geostationary Navigation Overlay Service) is a new satellite navigation system under development by the ESA (European Space Agency), the European Commission and EUROCONTROL. It is intended to supplement the GPS systems by reporting on the reliability and accuracy of the signals.

Power system

The nearspacecraft power system comprises of power source and power distribution. Power source in the nearspacecraft is a 14.8V (nominal voltage) lithium-ion battery-pack and power will be distributed to other sub-systems with DC-DC power supply and power bus providing 12V, 5V and 3.3V voltages.

Lithium ion batteries (sometimes abbreviated Li-Ion) are a type of rechargeable battery commonly used in consumer electronics. They are currently one of the most popular types of battery with one of the best energy-to-weight ratios, no memory effect and a slow loss of charge when not in use.

The nearspacecraft lithium-ion battery will be equipped with current, voltage and temperature monitoring equipment and with chemical heaters to ensure proper operational temperature during high-altitude flight.

Sensors

All sub-systems and electronics will be continuously monitored with temperature sensors connected to a common sensor bus. Also humidity of critical avionics components will be measured. The same sensor bus is used for measuring outside temperatures and humidity (for example shade and sunlight temperatures). 

The nearspacecrafts critical systems voltage is also monitored (such as the CPU and its associated electronics).