GPS Orion Receiver Development Page
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The GPS Orion receiver is a sample receiver design provided by Mitel Semiconductor
(now Zarlink).
It serves as a prototype for industrial GPS receivers built around the Mitel GP2000
chipset and is supplemented by the GPS Architect Software Development Kit (no longer
supported).
Last update: 18-OCT-2002
Created: 26-JUN-2002
Contact: Takuji Ebinuma
Firmware Modifications
For use on low Earth orbit satellites and other space applications, numerous
software modifications and enhancements have been made to the original
firmware of the Orion receiver. These modifications include the
fixes related to the implicit assumption of a low speed vehicle in the Doppler
prediction and the time tagging error of the raw measurements. Aside from these
fixes, an open-loop Doppler and visibility prediction algorithm has been added
to the receiver code to ensure a robust tracking and rapid signal acquisition
under the conditions of a high-dynamic space vehicle. Also, an
active alignment of measurement epochs and navigation solutions to the integer
second of GPS system time has been implemented, which ensures synchronized
measurements among multiple independent receivers. To improve the overall
navigation performance of the Orion receiver, integrated carrier phase
measurements have been made available using a 3rd order phase lock loop (PLL)
assisted by a 2nd order frequency lock loop (FLL). The loop
provides accurate tracking and stable acquisition over a wide range of
dynamic conditions. Raw measurement accuracies obtained in signal simulator
tests are better than 1m for C/A code pseudorange, 1mm for
L1 carrier phase, and 10cm/s for L1 Doppler measurements
in the absence of environmental error sources such as multipath.
Bill of Materials
The complete bill of materials, list of hardware vendors,
and helpful design and building information
will be available upon request.
Ongoing
10/18/2002: Finally, we received 10 Orion receivers!
10/08/2002: The navigation and raw data quality tests have
been performed for the engineering models.
The test procedures are defined by
Holt in his masters thesis.
10/07/2002: Two engineering models are delivered
for testing.
09/30/2002: The parts are sent to
Silicon Hills Design
for assembly.
09/09/2002: 20 PCBs for the main board are now in stock. We are
ready for assembly!
08/27/2002: PCBPro
delivered 20 PCBs for the interface board.
07/26/2002: The main board is in production.
07/22/2002: All the receiver parts except for the PCBs
are now in stock at CSR.
07/05/2002: The interface board is in production.
06/26/2002: The site was created.
Publications
Precise Spacecraft Relative Navigation Using
Kinematic Inter-Spacecraft State Estimates: T. Ebinuma,
O. Montenbruck, and E.G. Lightsey, ION GPS 2002, Portland, Oregon,
September 24-27, 2002.
Related Site
Orion GPS receiver development at
DLR/GSOC