The computationally intensive portions of MicroCosm® POD are embodied in MicroCosm® Executive. To provide users with a timing benchmark for MicroCosm® POD, a Seasat 7-day orbit was computed using three different gravity models: GEM-T1 (36x36), JGM-3 (70x70) and EGM-96 (360x360). Atmospheric drag, solar radiation pressure and solid Earth tides were also modeled. The spacecraft ephemeris was output every 15 minutes and the numerical integration was performed using a 60 second step size and 11th order. MicroCosm® Executive utilized approximately 24 MB of memory when processing with the EGM-96 gravity model instead of the approximately 2 MB of memory required for the smaller gravity models. A GPS precision orbit determination (POD) was also performed on these same computers. This POD determined the orbits of 22 GPS SV’s using 155,569 dual frequency double difference carrier phase measurements from 24 GPS receivers. A total of 2303 parameters were simultaneously adjusted including 132 orbit elements, 22 radiation coefficients, 66 GPS Y-bias accelerations, 183 tropospheric scale biases and 1900 carrier phase ambiguity biases. The results of these comparison are presented below:
| Computer Used | Execution Time | Sample Execution |
|---|---|---|
| HP 9000™ Model 782 w/ HP-UX™ 11.0, 200 MHz PA-RISC 8200 and 256 MB Memory. Computer was new in Dec 1998. |
4.99 Seconds 14.29 Seconds 594.56 Seconds 5870.06 Seconds |
GEM-T1 (36x36) JGM-3 (70x70) EGM-96 (360x360) GPS POD w/ JGM-3 (12x12) |
| Silicon Graphics Fuel w/ IRIX® 6.5, 700 MHz MIPS R16000 and 1.0 GB Memory. Computer was new in March 2004. |
2.48 Seconds 9.79 Seconds 309.32 Seconds 1803.62 Seconds |
GEM-T1 (36x36) JGM-3 (70x70) EGM-96 (360x360) GPS POD w/ JGM-3 (12x12) |
| Sun Blade 2000 w/ Solaris® 8, 1.2 GHz SPARC III Cu and 1.0 GB Memory. Computer was new in Sep 2003. |
1.93 Seconds 6.66 Seconds 127.74 Seconds 942.20 Seconds |
GEM-T1 (36x36) JGM-3 (70x70) EGM-96 (360x360) GPS POD w/ JGM-3 (12x12) |
| SGI Altix Prism w/ SUSETM Linux® 9.0, Dual 1.3 GHz Intel Itanium2 and 4.0 GB Memory. Computer was new in Jan. 2006. |
0.69 Seconds 1.97 Seconds 40.08 Seconds 398.81 Seconds |
GEM-T1 (36x36) JGM-3 (70x70) EGM-96 (360x360) GPS POD w/ JGM-3 (12x12) |
| Sun Sunfire X2200 w/ Solaris® 10, Dual-core 1.8 GHz AMD64® and 2.0 GB Memory. Computer was new in Mar. 2007. |
0.7 Seconds 2.4 Seconds 86.1 Seconds 394.4 Seconds |
GEM-T1 (36x36) JGM-3 (70x70) EGM-96 (360x360) GPS POD w/ JGM-3 (12x12) |
| Apple MacBook w/ OS X 10.5 Leopard, 2.4 GHz Intel Core 2 Duo, 256 GB Solid State Disk and 4.0 GB 1067 Mhz DDR3 Memory. Computer was new in Apr 2009. |
0.34 Seconds 1.03 Seconds 36.40 Seconds 191.49 Seconds |
GEM-T1 (36x36) JGM-3 (70x70) EGM-96 (360x360) GPS POD w/ JGM-3 (12x12) |
| H-P e9280t w/ Microsoft Windows 7 Ultimate 64, 3.33 GHz Intel Core I7 975 Quad Processor 18.0 GB 1067 MHz DDR3 Memory. Computer was new in Nov 2009. |
0.27 Seconds 0.92 Seconds 15.05 Seconds 122.40 Seconds |
GEM-T1 (36x36) JGM-3 (70x70) EGM-96 (360x360) GPS POD w/ JGM-3 (12x12) |
®H-P, HP 9000 and HP-UX are registered trademarks of Hewlett-Packard Corp.
®Fuel, IRIX, Altix and Prism are registered trademarks of Silicon Graphics, Inc.
®Blade and Solaris are registered trademarks of Sun Microsystems, Inc.
®SPARC III Cu is a registered trademark of SPARC International, Inc.
®AMD64 is a registered trademark of Advanced Micro Devices, Inc.
®MacBook and OS X Leopard are registered trademarks of Apple, Inc.
®Core 2 Duo and Core I7 are registered trademarks of Intel Corp.
®Itanium is a registered trademark of Intel Corp.
®Windows Xp Pro is a registered trademark of Microsoft Corp.
®Windows 7 Ultimate is a registered trademark of Microsoft Corp.
TMSUSE is a trademark of SUSE Linux, AG
®Linux is a registered trademark of Linus Torvalds
®MicroCosm is a registered trademark of Van Martin Systems, Inc.
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