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Protection Level Toolbox

version (36.7 KB) by Dean Bruckner
Simulates protection levels for GPS precision approach and landing


Updated 29 Jan 2014

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Provides easy-to-use tool to evaluate protection levels that provide integrity to GNSS solutions for precision approach and landing

Begins with the vertical protection level (VPL) and horizontal protection level (HPL) of the type used in the U.S. Local Area Augmentation System (LAAS) and Wide Area Augmentation System (WAAS). Illustrates computation of exact VPL and HPL values for the newer composite protection level, and provides less computationally-intensive approximations that over-bound these exact values.

Allows developer to evaluate new protection level types and compare them against known types.

Also implements exact and approximate methods of new composite radial protection level (RPLc) that may become useful in relative navigation, particularly with unmanned systems.

MATLAB command window simulation of a single GPS measurement epoch from the 24-satellite GPS constellation. User sets range-domain parameters for noise, bias, and residual ionospheric and tropospheric errors and observes how these errors translate into the position domain. May be used to support GNSS availability simulations (not included).

Provides useful algorithms and plots to the user for further development. Contains user quick start guide and extensive comments in the code.

Supported by the following peer-reviewed journal articles and dissertation:

D. Bruckner, F. van Graas and T. Skidmore, "Algorithm and Flight Test Results to Exchange Code Noise and Multipath for Biases in Dual Frequency Differential GPS for Precision Approach," Navigation, Vol. 57, No. 3, Fall 2010, pp. 213-229. Available at

D. Bruckner, F. van Graas and T. Skidmore, "Statistical Characterization of Composite Protection Levels for GPS," GPS Solutions, Online First publication in November 2010, doi:10.1007/s10291-010-0193-5, available online at

D. Bruckner, F. van Graas and T. Skidmore, "Approximations to Composite GPS Protection Levels for Aircraft Precision Approach and Landing," GPS Solutions, Online First publication in December 2010, doi:10.1007/s10291-010-0188-2, available online at

D. Bruckner, "On the Treatment of Noise and Conspiring Bias in Dual-Frequency Differential Global Navigation Satellite Systems," Ohio University dissertation, June 2010. Available at

Other references include the following:

"Minimum Aviation Systems Performance Standards (MASPS) for the Local Area Augmentation System (LAAS)," RTCA DO-245B, 2007, available for purchase from

D.J. Torrieri, "Statistical Theory of Passive Location Systems," IEEE Transactions on Aerospace and Electronic Systems, vol AES-20, No. 2, March 1984.

J. Sheil and I. O'Muircheartaigh, "Algorithm AS 106: The Distribution of Non-Negative Quadratic Forms in Normal Variables", Applied Statistics, Vol. 26, No 1 (1977), pp. 92-98. Blackwell Publishing for the Royal Statistical Society. See http//

D.Y. Hsu, Spatial Error Analysis, New York: IEEE Press, 1999, with free Matlab toolbox available for download at

Cite As

Dean Bruckner (2020). Protection Level Toolbox (, MATLAB Central File Exchange. Retrieved .

Comments and Ratings (1)


Updated web link

One more formatting change in description. No code changes.

Updated description only. Did not change any code.

MATLAB Release Compatibility
Created with R2007b
Compatible with any release
Platform Compatibility
Windows macOS Linux