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Unformatted text preview: Statistic:
• A satellite SPS SIS URE statistic is defined to be the Root Mean Square (RMS)
difference between SPS ranging signal measurements (neglecting user clock bias and
errors due to propagation environment and receiver), and “true” ranges between the
satellite and an SPS user at any point within the service volume over a specified time
interval. • A constellation SPS SIS URE statistic is defined to be the average of all satellite SPS SIS
URE statistics over a specified time interval. Page B-3 October 2001 GPS SPS Performance Standard Steady-State Behavior: Behavior within statistical expectations.
Time Transfer Accuracy Relative to UTC (USNO): The difference at a 95% probability between
user UTC time estimates and UTC (USNO) at any point within the service volume over any 24hour interval.
Transient Behavior: Short-term behavior not consistent with steady-state expectations.
Usable SPS Ranging Signal: An SPS ranging signal that can be received, processed, and used
in a position solution by a receiver with representative SPS receiver capabilities.
User Navigation Error (UNE): Given a sufficiently stationary and ergodic satellite constellation
ranging error behavior over a minimum sample interval, multiplication of the DOP and a
constellation ranging error standard deviation value will yield an approximation of the RMS
position error. This RMS approximation is known as the UNE (UHNE for horizontal, UVNE for
vertical, and so on). The user is cautioned that any divergence away from the stationary and
ergodic assumptions will cause the UNE to diverge from a RMS value based on actual
User Range Accuracy (URA): A conservative representation of each satellite’s expected (1σ)
SIS URE performance (excluding residual group delay) based on historical data. A URA value is
provided that is representative over the curve fit interval of the navigation data from which the
URA is read. The URA is a coarse representation of the URE statistic in that it is quantized to the
levels represented in ICD-GPS-200C. Page B-4 October 2001 GPS SPS Performance Standard SECTION B-2 Acronyms
BPSK International Bureau of Weights and Measures
bits per second
Bipolar-Phase Shift Key C/A
Control Segment dBi
DOT Decibels, isotropic
Department of Defense
Dilution of Precision
Department of Transportation ECEF
ERD Earth-Centered, Earth-Fixed
Estimated Range Deviation FAA
FRP Federal Aviation Administration
Full Operational Capability
Federal Radionavigation Plan GEC
GA Groundtrack Equatorial Crossing
Global Positioning System
Geographic Longitude of the Ascending Node
Ground Antenna HDOP
HUNE Horizontal Dilution of Precision
Hazardously Misleading Information
Horizontal Component of the User Navigation Error ICD
ION Interface Control Document
Interagency GPS Executive Board
Initial Operational Capabili...
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This document was uploaded on 09/26/2013.
- Fall '09