NDLI: Global implications on the removal of selective availability

Content Provider	IEEE Xplore Digital Library
Author	Conley, R. Lavrakas, J.W.
Copyright Year	2000
Description	Author affiliation: Overlook Syst. Technol. Inc., USA (Conley, R.)
Abstract	In March 1996, President Clinton issued a Presidential Decision Directive (PDD) that directed the Department of Defense (DoD) to discontinue the use of selective availability (SA) by the year 2006, with annual reviews of the DoD's status in preparing for the event beginning in 2000. Unless the DoD presents compelling evidence to counter the PDD, SA will transition to an "off" state within the next few years. The purpose of this paper is to explore the ramifications of removing SA from the standard positioning service (SPS). The paper summarizes expected GPS orbit and clock error behavior in the absence of SA, and how those errors map into signal-in-space (SIS) user range errors (UREs). This data is then used to assess expected instantaneous position solution errors on a global basis, using the current constellation. This analysis serves to demonstrate the core contribution of the GPS space and control segments to SPS accuracy. The GPS Modernization Program being executed by the GPS Joint Program Office (JPO) includes a new civil signal that will provide SPS users with a two-frequency ionosphere delay correction capability. However, it will be several years before this capability is available, so single-frequency model errors will still be part of the SPS user's error budget. The paper summarizes an analysis of measured errors in the single-frequency model based upon correlations between the single frequency model and two-frequency measurements taken over an extended period of time from the Federal Aviation Administration's (FAA) National Satellite Test Bed (NSTB). This error information is then added to our SIS URE dataset, and instantaneous position solutions including the single frequency error are generated. The paper then discusses the implications our findings have for the global positioning/navigation/timing (PNT) infrastructure. The paper provides a summary of how well GPS will support a wide assortment of user communities, and discusses the policy considerations implicit in the decision to discontinue the use of SA.
Starting Page	506
Ending Page	513
File Size	898273
Page Count	8
File Format	PDF
ISBN	0780358724
DOI	10.1109/PLANS.2000.838346
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2000-03-13
Publisher Place	USA
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Global Positioning System Extraterrestrial measurements Frequency measurement Time measurement FAA Counting circuits Clocks Ionosphere Delay Error analysis
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in