IPU
type: Concept
in scheme: instruments
definition: The GRACE Instrument Processing Unit (IPU) is part of the GRACE Instrument System (IS) consisting of an Ultrastable Oscillator (USO), a K-band Ranging Assembly (KBR), a Star Camera Assembly (SCA) and an Accelerometer (ACC). Most of these systems are fully redundant. The function of the IPU is to + receive, downconvert and digitize GPS signals, + extract observables from KBR and SCA and report, + provide timing reference to the satellite bus and ACC, and + calculate GPS navigation solution (position, velocity and time). [Summary from GRACE IPU Specification Document] Group: Instrument_Details Entry_ID: IPU Group: Instrument_Identification Instrument_Category: Earth Remote Sensing Instruments Instrument_Class: Passive Remote Sensing Instrument_Type: Positioning/Navigation Short_Name: IPU Long_Name: Instrument Processing Unit End_Group Group: Associated_Platforms Short_Name: GRACE End_Group Online_Resource: http://www.csr.utexas.edu/grace/spacecraft/sis.html#sis2 Online_Resource: http://www.csr.utexas.edu/grace/ Online_Resource: http://nasascience.nasa.gov/missions/grace Online_Resource: http://podaac.jpl.nasa.gov/grace/ Creation_Date: 2007-05-02 Group: Instrument_Logistics Instrument_Owner: USA/NASA End_Group End_Group

Positioning/Navigation
type: Concept