TDRSS Link Budget Design Table

Abstract

The Consultative Committee for Space Data Systems (CCSDS) has issued a Recommendation CCSDS 401.0-B for Radio Frequency and Modulation Systems to be used in Earth stations and spacecraft. Part of this Recommendation is a standardized design tool for link budget computations. This design tool is intended to assist spacecraft designers in preparing the power and performance designs of their spacecraft for communicating with existing standard ground stations. The present CCSDS Recommendation addresses a link design typical for that found with the Deep Space Network (DSN). DSN link analyses use a large subset of link-specific parameters not of any particular use if the space data link passes through the Tracking and Data Relay Satellite System (TDRSS). The link architecture also differs in that the TDRSS parameter set needs to include an extra link through the satellite (two-hop) link versus a DSN-type link which is single-hop. Conversely, the treatment of ranging, PN coding requirements, and TDRSS acquisition and data group formalities are either not of the same format or not present at all on the DSN-type links. The baseline CCSDS 401 design tool is a Microsoft Excel spreadsheet that can run on an IBM PC or compatible computer. This baseline spreadsheet has been modified to account for the differences between baseline CCSDS model and TDRSS link operations. The paper will discuss the modifications made to the spreadsheet for the TDRSS system details. We will also present example usages of the spreadsheet.