Performance of Stand-Alone GPS - Understanding GPS: Principles and Applications - page 375

Table 7.17 Comparison of Typical Performance Range Across Various Receivers
Comparative 95% Three-Dimensional
Position/Time Error Across Various
Receivers

SPS PPS

Best
Location

Median
Location

Worst
Location

Best
Location

Median
Location

Worst
Location

Handheld (best 4-SV solution) 16m 32m 72m 10m 30m 71m

Handheld (AIV solution) 11m 25m 54m 8m 23m 53m

Mobile (land/marine vehicle) 7m 23m 53m N/A N/A N/A

Aviation receiver (AIV, RAIM,
tightly coupled with INS)

7m 24m 55m 4m 5m 6m

Survey receiver (dual-frequency,
real-time performance)

3m 4m 5m 3m 4m 5m

Aviation receiver dynamic
time transfer performance

14 ns 45 ns 105 ns 12 ns 13 ns 14 ns

Time transfer receiver static
time transfer performance

10 ns 19 ns 35 ns 10 ns 10 ns 11 ns

Analysis notes:
• Performance reported in the table is based on a 24-hour assessment period, using the full operational GPS constellation as of July 2004.
Performance variations increase as satellites are removed from the constellation or environmental conditions degrade from the assump-
tions used to generate the table.
• The distinction between SPS and PPS is the use of C/A versus P(Y) code. For dual-frequency receivers, the distinction is the ability to
code track on L2 for PPS receivers versus the use of semicodeless L2 tracking techniques for SPS.
• Ionosphere conditions and associated single-frequency model errors are based on a “typical” day. No scintillation effects are included.
• Each receiver antenna is assumed to be oriented with its bore sight aligned with local vertical.
• A nominal noise environment and no overhead canopy or other shielding is assumed. The effect of these assumptions is to maximize
C / N 0 for each receiver/satellite link.
• Note that SPS aviation receiver performance is represented without augmentation (such as the WAAS in the United States). WAAS (and
other similar international systems) provides significant accuracy improvement for its area of operations.
• Aviation receiver performance assumes the use of a RAIM algorithm, tightly coupled with an INS.
• No terrain above the receiver-specific mask angle was included in this analysis.
• The survey receiver's tracking loop noise contribution to URE was based on carrier, not code. The dominant survey receiver error in the
absence of environmental noise is signal-in-space URE.
• Representing survey receiver performance as a 95th percentile can be misleading, since the very high accuracies achieved by survey
receivers comes from averaging measurements over a user-specified time interval. Survey receiver performance is presented earlier as a
95th percentile statistic only to illustrate the range of possible receiver performance.
• Time transfer performance numbers for either a positioning or time transfer receiver represent the accuracy of internal receiver compu-
tations and presentations to the user. They do not include errors associated with generating a time mark pulse for use by other equip-
ment outside the receiver. Depending on the receiver, this error can be significantly greater than the error of the PNT solution itself.

References

[1] Ward, P., “An Inside View of Pseudorange and Delta Pseudorange Measurements in a Digi-

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Civil Applications, San Diego, CA, October 14, 1981, pp. 63-69.

[2] van Graas, F., and M. Braasch, “Selective Availability,” in Global Positioning System: The-

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[3] The White House, Office of the Press Secretary, “Statement by the President Regarding the

United States' Decision to Stop Degrading Global Positioning System Accuracy,” White
House Press Announcement, May 1, 2000.

[4] ARINC Research Corporation, NAVSTAR GPS Space Segment/Navigation User Inter-

faces , Interface Specification, IS-GPS-200D (Public Release Version), ARINC Research
Corporation, Fountain Valley, CA, 2004.

[5] Dieter, G. L., G. E. Hatten, and J. Taylor, “MCS Zero Age of Data Measurement Tech-

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