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Document Title: 4
User’s Manual for the GPS Orion-S/-HD Receiver
Document No. Issue 1.0
GTN-MAN-0110 June 22, 2003
DLR/GSOCNo part of this document shall be reproduced in any form or disclosed to third parties without prior authorization.
• Small form factor (50 x 95 mm) and weight (50 g)
• Sufficient radiation tolerance LEO usage
• Battery buffered non-volatile memory and real-time clock
• Two serial ports
• Discrete input pin
• 5V supply for active antenna (16-28dB)
• OrionMonitor control software for Windows PCs
A hardware description of the Orion-S/HD receiver is provided in Chap. 2 of this manual.
Chap.3 addresses the receiver operation and the command and log functionality is described
in full detail in Chap. 4.
1.3 Receiver Versions
The Orion receiver is available in various versions, which basically differ by the employed
receiver software. Aside from the standard receiver (Mitel reference design [3], [4]), which is
restricted to terrestrial applications, a space (-S) version and a high dynamics (-HD) version
are available. These employ specific trajectory models to enable a safe and rapid signal ac-
quisition under rapid motion of the host vehicle. For satellites in low Earth orbit, aiding is pro-
vided by an analytical orbit model using twoline elements, whereas a set of piecewise poly-
nomials is employed to approximate the trajectory of ballistic vehicles (sounding rockets, re-
entry capsules) in the HD version. Various commands specific to each of these versions are
provided to load, dump and use the respective aiding information.
The two versions also differ by their choice of FLL/PLL loop settings that are adapted to the
specific application needs. A narrow bandwidth of the carrier tracking loop is chosen in the
Orion-S receivers to achieve the most accurate carrier phase measurements under typical
line-of-sight accelerations of 1 G. Wide bandwidth settings, in contrast are chosen for in the
HD receivers to accommodate the extreme dynamics of a powered flight and the re-entry
shock.
Finally, a relative navigation mode is offered by the Orion-S receiver to support its use in
basic formation flying and rendezvous & docking applications.
A detailed account of the prototype software for the GPS Orion receiver is given in the GPS
Architect Software Design Manual [5]. Subsequent modifications for the S and HD version
are described in [6].