Changes between Version 18 and Version 19 of TBR/UserApp/Space/Proba_2

Nov 29, 2011, 10:18:39 PM (8 years ago)


  • TBR/UserApp/Space/Proba_2

    v18 v19  
    173173compensation of thermo-elastic misalignments of the star tracker relative to the instrument.
    176 [wiki:File:PROBA2_Auto2.jpeg File:PROBA2 Auto2.jpeg]
    177 Phoenix GPS architecture for PROBA-2
    179 It is a miniature receiver specifically designed for high dynamics space applications. It is based on SigTech’s
    180 commercial-off-the-shelf MG5001 receiver board but operates a proprietary firmware developed by DLR.
    181 Though originally designed for automotive applications, the receiver board has been qualified for space use in a
    182 series of thermal-vacuum, vibration and total ionization dose tests. The receiver employs a GP4020 baseband
    183 processor which combines a 12 channel GP2021 correlator and an ARM7TDMI microprocessor kernel.
    184 At a power consumption of less than one Watt and a board size of 50 x 70 mm the receiver is among the
    185 smallest of its kind and particularly well suited for satellites with limited onboard resources. The Phoenix
    186 receiver is extensively used in European sounding rocket missions and has been selected for various other
    187 micro-satellite missions in low Earth orbit (LEO) such as X-Sat, ARGO, Flying Laptop and PRISMA. Specific
    188 features of the Phoenix receiver software for LEO applications include optimized tracking loops for high
    189 accuracy code and carrier tracking, precision timing and integer ambiguities for carrier phase based relative
    190 navigation, a twoline elements orbit propagator for signal acquisition aiding, and an attitude interface to
    191 account for non-zenith pointing antennas in the channel allocation process. A pulse-per-second signal enables
    192 synchronization to GPS (or UTC) time with an accuracy of better than 1ms. Noise levels of 0.4 m (pseudorange)
    193 and 0.5 mm (carrier phase) at representative signal conditions (C/N0=45dB-Hz) have been demonstrated in
    194 signal simulator and open air tests which render the receiver suitable for precise orbit determination. While
    195 the instantaneous (kinematic) navigation solution is restricted to an accuracy of roughly 10m (3D rms) due
    196 to broadcast ephemeris errors and unaccounted ionospheric path delays, an accuracy of about 0.5-1m
    197 can be achieved in a ground based precise orbit determination.
    199175The orbital information allows pointing of the  spacecraft towards any point on Earth (by using as well