For many years I have been involved with an organisation called AMSAT-UK whose goal is to support the design and building of Amateur (OSCAR) Satellites, CubeSats, MicroSats, and associated ground infrastructure, worldwide. The organisation exists by DONATIONS and the many hours put in by it's members, in performing its goals.
About 4 years ago we were approached by the Radio Communication Foundation (RCF), who had received a legacy who specific requirements were for the building of an educational satellite. As a result of this, we had to:
- Decide if we could do it at all
- Identify the volunteers who had the necessary skills
- Identify a lauch provider
- Define the functional requirements
- Identify COTS devices/hardware which would full-fill some of the requirements.
- Design, build and test
- the hardware
- the flight software
- the ground station software
- the telemetry data warehouse
Now, four years later we have done all those things and we are expecting a launch in late November, 2013.
The image you can see on the right is the actual Flight Model of FUNcube-1, a 10cm cube weight just under a kilogramme.
The primary mission is to provide downlink telemetry that can be easily received by schools and colleges for educational outreach purposes.
The target audience is primarily students at both primary and secondary levels and the project includes the development of a simple and cheap “ground station” operating on VHF frequencies in the Amateur Satellite Service.
My involvement in the project was the design and development of the FUNcube Data Warehouse.
The intention of the warehouse is to allow access to all the data received for the duration of the mission rather than from just one or a series of passes. This will enable educators and others to download mission telemetry for off-line analysis as part of our STEM outreach goal.
The warehouse will store information for the following satellites/devices:
- FUNcube Flight Model
- UKube-1 - FUNcube module
- FUNcube Engineering Model (which will be used for some demonstrations)
- FUNcube Software Test Stack (which is still be used for development but may become another demonstration model later)
I am indebted to Black Pepper for allowing me to use one of their internal projects 'Serenity', a RESTful stack, in one of the early prototypes of the warehouse. Since then the warehouse has been written as a greenfield agile project using the following technologies:
- Hibernate / JPA
- Spring MVC
- Spring Security
- Spring Web Services
- Hicharts JS
In addition to the Data Warehouse, we have developed
- a USB Software Defined Radio (SDR) know as the FUNcube Dongle which is a wide-band receiver, intended for use in schools and by other to receive the satellite
- a C#/WPF PC desktop Dashboard application which will, using the dongle, or a suitable shortwave receiver, decode, display and upload the telemetry to the Data Warehouse.
In order to stop erroneous telemetry packets being uploaded from the Dashboard to the Warehouse we transmit some user information and a SHA1 digest of the packet as part of the RESTful POST request. The digest is recreated on the server, based on a shared key that we provide to the user during registration.
During our testing of the telemetry pipeline:
FUNcube EM, transmitting telemetry on a VHF frequency -> receiver and demodulated by the FUNcube Dongle -> decoded by the FUNcube Dashboard -> uploaded over the internet -> collated, decomposed, de-duplicated, stored and displayed by the FUNcube Data warehouse
We ran the system for over 6 weeks without missed packet, including restarting the Data Warehouse for upgrades (the Dashboard backs off and retries later).
In light of the work we have done on all the systems, it is likely that there will be a several generations of FUNcube, either as stand alone satellites or as modules on board other educational satellites.
We are looking forward to a late November launch. News updates can be found here: