Ground Sphere Mk 3

h1. Link Budget References

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The resources pages are used as a central repository of technical research.  This topic page covers research into Link Budgets.  Link Budgets are critical tools in predicting the performance of radio based communications, including from satellites to ground stations.  See the Background Material for details about how Link Budgets work.

h2. Background Material

* "Link Budget Calculation":http://www.piscespacific.org/livesite/files/Link_Budget_Calculation.pdf

* "Tutorial on Basic Link Budget Analysis":http://www.sss-mag.com/pdf/an9804.pdf

* [[Link Budget Video Tutorials]] by Aaron Harper, Mach 30 volunteer

h2. Example Calculations

Much of this material was reviewed with the stakeholders and the IPT at the "Sprint 1 Stand Up 3 meeting":https://docs.google.com/document/d/17Wc4sMqlUissR5am6ANDcKP-psRQ41ysxOV0vrcgHJA/pub

h3. Online Forms

Online forms are useful for one off calculations, source code/math not necessarily available to Mach 30.

* "Satellite Link Budget Calculator":http://www.satsig.net/linkbugt.htm - simple online form for uplink and downlink calculations

* "Satellite Link Budget Calculator page":http://www.tutorialsweb.com/satcom/satellite-link-budget-calculator.htm - a mor complete set of calculations for uplink and downlink

* "Geostationary Satellite Link Budget Calculations (Downlink)":http://www.satcom-services.com/VSAT/downlink.html - Geo calculations, not really useful for us, but nice user experience

h3. Spreadsheets 

Spreadsheets require the correct software to run (typically MS Excel), but Mach 30 can investigate the implementation to use as a source for porting to Python library.

* "KickSat Ground Station Link Budget":https://github.com/kicksat/groundstation/blob/master/Link%20Budgets.xlsx (MS Excel) - just about the right level of detail for current work (not surprising since KickSat has a similar level of technical complexity and available technical resources as Ground Sphere)

* "Jan King's AMSAT link budget":http://www.amsatuk.me.uk/iaru/AMSAT-IARU_Link_Model_Rev2.5.3.xls (MS Excel) - the most extensive calculations, too much detail for now, but will likely be useful for future projects

* "KA9Q JJSat link budget design spreadsheet":http://www.ka9q.net/jjsat/full_links.xls (MS Excel) - another set of right sized calculations for our current needs (came from "conceptual design work for JJSat":http://www.ka9q.net/jjsat/)

* "ConaSat Link Budget Calculations for DTUSat":http://www.crn2.inpe.br/conasat1/projetos_cubesat/projetos/DTUSat%20-%20Technical%20University%20of%20Denmark%20-%20Denmark/DTUSat%20-%20COM%20-%20Link%20Budget.xls (MS Excel) - the history of this spreadsheet is a little unclear, but it is a very clean implementation of the required calculations

h2. Selected Link Budget Source Document

The Ground Sphere Mk 3 team has decided to build its Python Link Budget library on the calculations used in the "KickSat Ground Station Link Budget":https://github.com/kicksat/groundstation/blob/master/Link%20Budgets.xlsx.  This spreadsheet includes nearly all of the required transmission effects and has been verified by "comparing its results to manual calculations":http://opendesignengine.net/dmsf_files/523?download=.