Index by title

Block Diagram

The discussion leading to this block diagram can be found in the forums here

Initial Questions

The discussion that led to this set of initial questions can be found here

Q1. Why are we making this?

Tracking, communication, and command & control of spacecraft are essential capabilities for a spacefaring civilization. Ground stations are the principle links between the spacecraft and Earth used to facilitate these capabilities. The series of ground station related projects will develop the necessary open source hardware to perform these functions.

Q2. Who is this for?

Mach 30 volunteers, Makerspaces and their members, CubeSat designers and operators (including universities). With some minor modifications, most of them software, radio astronomers could be added to the list of users as well.

Q3. How will this be used?

Early ground stations will be used to facilitate voice communications with orbiting satellites (including the ISS, HAM satellites, and CubeSats). Note, not all satellites will support voice communications, in which case the early ground stations will simply provide a means of listening to the satellites' other radio signals. Data capabilities can be added easily to the system, either by demodulating the audio stream (as in a computer modem), or by using an Software Defined Receiver (SDR) such as the AMSAT Funcube Dongle or USRP and running the demodulation through a software module (GNU radio) using a PC or Laptop.

Q4. What features does it need to have (now)?

Ability to predict opportunities for contact, and the ability to receive and send voice traffic.

Q5. What features does it need to have (later)?

In the future, our ground stations should be able to support sending and receiving command and control data from orbiting spacecraft. For command and control a tracking system would be required since those channels tend to be in a higher frequency range and thus will need a dish. This means that directional antennas and antenna rotator will be required. Additionally, it would be interesting to investigate the possibility of linking multiple ground stations together to provide larger coverage area (imagine if makerspaces across the country, or world, had ground stations linked over the internet so smaller satellite operators could have greater coverage and contact to their satellites). Linking would require standardized equipment with the audio stream being synched by a precision GPS timebase. This will probably be necessary for radio science and video applications as well. For something similar in many ways, have a look at http://www.irlp.net/

Q6. What are the legacy requirements?

Transmitting will require HAM radio licenses (technician level or greater) in the US. Other countries may have other requirements.

Q7. Who's going to build this?

This is a point of discussion, since the current 2013 Mach 30 Annual Plan does not yet have hardware expenses budgeted for this project. This project may be built entirely through volunteer work and funding under the Mach 30 banner though.

Q8. How many do we want to make?

This is a great opportunity to develop a kit which individuals, makerspaces, universities, etc could build and set up. We can kitify the omni antenna, for the starter level project and the Yagi antennas and rotator from later versions.

Q9. What is the budget?

Individual level 1 kites have a budget of approximately $200. However, this project will clearly have multiple kites, so the over all budget will go much higher. Current estimates are about 5 kites or about $1000. This budget leaves out the expense of radio(s) and additional equipment to keep the entry level version at a level 1 kite tier.

Q10. What is the timeline?

TBD - again the current 2013 Mach 30 Annual Plan did not budget for this to go into production so quickly (we did not anticipate increased levels of participation coming so quickly). The volunteer timeline for the first prototype unit is intended for use within 2013.

Q11. What waste products will be produced by the manufacture and/or operation of this?

TBD - It is most likely that elements from earlier version will be reused or kept as backups. Any components that wear out, fail, or are damaged must be disposed up according to all federal, state and local guidelines in the US, or as regulations require in other parts of the world.

Licensing and Attribution

Hardware - Mach 30 Open Design Pledge
Software - GNU General Public License, version 3.0
Documentation - Creative Commons Attribution

Ground Station Requirements Document v1.0

Introduction

This requirements document is currently being discussed on the forums here. The requirements list matches up to the Initial Questions in step one of the Systems Engineering process as shown below. Each requirement is labeled with GSR (Ground Station Requirement), followed by the number of the initial question that the requirement corresponds to, followed by a dot and then the ID number of the requirement.

Technical Requirements

Technical requirements are those requirements which include measurable performance values. Each technical requirement should be verified through testing to ensure the design meets the requirement.

Project Requirements

Project requirements are the remaining requirements which are not tied to specific performance values.

Future V2.0 Requirements

These are for reference only so that future features can be accommodated in the current design where practical.

Version 2.0: Beyond Version 2.0:

Glossary

Azimuth - A coordinate system of relative direction based upon polar direction in degrees parallel to the ground where 0 is true north.
BNC - A type of quick disconnect radio frequency connector which needs no tools to connect or disconnect from the jack.
Consumables - Items that are used and then discarded such as nylon zip ties or cleaning wipes.
Demodulation - The conversion of an analog signal to audio or digital information.
Directional - In this context, antennas which function best in one direction.
Dish - Parabolic dish (short form). In this context, a highly directional antenna system characterized by a parabolic reflector dish and a feed horn in the focal point.
Doppler shift - Frequency shift caused by relative motion between the sender and receiver.
Downlink - The signal from a spacecraft to the ground station(s).
Duplex - In this context, the capability to send and receive at the same time.
Elevation - A coordinate system of relative direction ranging from 0 degrees, parallel to the ground, to 90 degrees, straight up or zenith.
Feed Horn - A radio antenna and in some cases preamplifier (LNA) fixed to the vocal point of a parabolic dish.
Full Duplex - See Duplex.
GPS - Global Positioning System. While primarily used for navigation, the signal contains a precision time base.
GS - Ground Station (short form).
Half Duplex - The ability to transmit or receive, but not at the same time.
Ham - Amateur radio operator.
HT - Handheld Transceiver
IAW - In Accordance With (short form).
Kitified - Designed to be made into a kit.
L-band - In this context, the Amateur radio frequency range from 1,240 to 1,300 MHz. Amateur satellite up-links are in the frequency range from 1,260 to 1,270 MHz
LNA - Low Noise Amplifier. A high performance antenna and preamplifier combined in a single assembly mounted to the focal point of a parabolic dish.
Modulation - Embedding an analog or digital information on an analog signal.
Omni - See Omnidirectional
Omnidirectional - In this context, antennas capable of functioning in any direction
OH - Open Hardware
OS - Operating System, also Open Source
Preamp - See Preamplifier
Preamplifier - An amplifier designed to be mounted between an antenna and radio receiver.
Repeater - A transciever set up to rebroadcast a signal on a different frequency for extended coverage.
RF - Radio Frequency
Rotator - A device to point a dish or directional antenna at the signal source, in this context a satellite.
SDR - Software Defined Radio. A radio system where its capabilities and tuning are defined in software.
Sensitivity - The ability of a radio receiver to pick up a faint signal. Measured in -dB where a higher negative number is more sensitive on a logarithmic scale.
SWR - Standing Wave Ratio. A factor of antenna system efficiency based upon matching components. Measured in a ratio with no units.
Timebase - In this context, a time measurement system which may be synchronized with others using a central source.
Transceiver - A transmitter and receiver combined in one physical unit.
UHF - Ultra High Frequency. In this context, the amateur radio UHF band from 430 to 440 MHZ.
Uplink - The signal from the ground station to the satellite.
USB - Universal Serial Bus. A physical data transfer standard for computer equipment.
VHF - Very High Frequency. In this context, the amateur radio VHF band from 144 to 148 MHz.
VPN - Virtual Private Network. A private and secure method of transferring data on the public Internet.
VSWR - See SWR.
Yagi - A type of directional antenna characterized by multiple straight elements mounted in parallel on a common backbone.

Navigation

Ground Station

Systems Engineering Process

  1. Initial Questions
  2. Requirements Document
  3. Block Diagram
  4. Architecture Study
  5. Preliminary Design
  6. Detailed Design
  7. Design Review
  8. Procurement/Manufacture
  9. Assembly
  10. Integration
  11. Testing
  12. Disposal

Documentation

  1. Budget
  2. Timeline
  3. BOM
  4. Schematics and PCB Files
  5. Software Source Code
  6. Assembly Instructions
  7. Operating Manual
  8. Safety Procedures
  9. Software/Firmware Summary
  10. Meeting Minutes
  11. Licensing and Attribution
  12. Errata

Wiki

Welcome to the Ground Station project Wiki. This wiki contains documentation covering the design, development, fabrication, and use of the ground station. Much of the information here started life over in the forums, where we held discussions and worked to achieve a consensus on all items. Due to this, the forums would be a good place to start if you have questions about the thought process behind an item. In most cases, links to the appropriate forum discussions will be included in the wiki pages.

The idea behind the Ground Station project is to start small and simple, and then build on what is learned when moving to larger and more complex stands later on. This is very much in keeping with Mach 30's philosopy of starting (literally) from the ground up to build the infrastructure required to facilitate safe, routine, reliable, and sustained access to space. TODO: Talk about what the multiple iterations will include.

If you're interested in getting involved a good place to start would be the Initial Questions page. There you will find the foundational questions that will guide the rest of the Ground Station design process. There is also the navigation bar at the right to help you find a specific section of the documentation quickly.