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TOPIC: Calculation of Target Location Error (TLE)

Calculation of Target Location Error (TLE) 2 years 4 months ago #819

  • adamemond
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Refs: A. US JP 3-09.3, 25 November 2014, “Close Air Support”
B. ACIC Technical Report No. 96, Greenwalt, Clyde R., and Schultz, Melvin E., Reprinted June, 1968, “Principles of Error Theory and Cartographic Applications”
C. Hurwitz, Arnon, & Kitto, William, & Remund, Todd, & Brownlow, James (2011). Estimation of Location Error for Targeting Using Parametric, Monte Carlo, and Bayesian Techniques in ITEA Journal “Rigor of the Scientific Method”
D. Meidunas, Eduardo C. 2008. Estimating elliptical error probable confidence intervals for weapons system performance evaluation. Air Force Operational Test and Evaluation Center, Kirtland Air Force Base, Albuquerque, NM.
E. Olsen, Grant M., Robinson, Timothy J. & Anderson-Sprecher, Richard. (2013). "Methods for Estimating the Upper 90th Confidence Limit on the 90th Percentile of Target Location Errors in Munitions Testing" in ITEA Journal.

I am looking for a standardized approach to calculate TLE Categories based on calculations of CE90 and VE90.

I am looking at the accuracy of the geo-coordinates generated by an EO/IR pod. The errors will be expressed in the context of a US joint publication (ref A Ch III para 11. c.) that defines TLE Categories in terms of CE90/VE90. These TLE Categories are the standard to which our Forward Air Controllers (FAC) are trained. I.e., if they tell an air asset that they are designating a set of co-ordinates X with a certain CAT, the pilot may not need to confirm the target location, and can release weapons.

The issue I am having is calculating CE90/VE90 from a data set. I will be using a definition of CEP/VEP and the relation to CE90/VE90 from a 1968 report (ref B). My concern is that the potential data for the EO/IR pod being tested may not satisfy the assumptions (distribution of errors, types of errors) to utilize the approximations in the 1968 report (ref B). I have found a number of other articles (e.g., ref C, D and E) that seem to provide alternate methods. I believe that errors in EO/IR coordinate generation are similar to errors in weapons testing, and that similar analysis methods can be used.

I haven't been able to find a STANAG, US DOD, or other collectively approved approach to calculate CE90/VE90, along with the assumptions that need to be satisfied. Given how TLE Categories are used (i.e., by FACs to potential authorize weapons release), I find this odd. Can any one point me in the right direction?

Calculation of Target Location Error (TLE) 7 months 1 week ago #950

  • Jordan
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Bump. I get how to find the CEP (Measure distance off target & record these numbers. Square each number in the list individually. Find the average of all the squared numbers. Find the square route of the average of all the numbers to determine the circular error of probability.), but that just gets you the average. It's the formula for finding the 90% that I am having a hard time with.

Calculation of Target Location Error (TLE) 5 months 2 weeks ago #961

  • markjonesjr
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CE and VE are just confidence intervals. I say "just" but confidence intervals are not intuitive and are actually quite hard to truly understand. However, computing confidence intervals is elementary.

Computation of the Circular Error Probable and Confidence Intervals in Bombing Tests is one US DoD reference and is here: www.dtic.mil/dtic/tr/fulltext/u2/a476368.pdf .

Airborne Laser Systems Testing and Analysis is an authoritative/relevant NATO document and is here: www.dtic.mil/dtic/tr/fulltext/u2/a534869.pdf .
Sincerely,
Mark "SCIPR" Jones Jr.

Calculation of Target Location Error (TLE) 5 months 2 weeks ago #962

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I found some Canadian specific references as well:
"Once a weapon ballistic algorithm has been validated, the overall accuracy of this weapon when released from different types of aircraft must be estimated and validated. To estimate an aircraft weapon system overall accuracy when releasing a specific weapon, circular error probable (CEP) values are determined within 20 percent of their true values with a 95-percent confidence level. This means that at least 47 independent statistically successful weapon releases are necessary to achieve such an estimation.
Once this specific aircraft/weapon CEP has been estimated, the number of test points required to validate it is calculated following the procedure outlined in the AETE Technical Memorandum No. 597. In short, a test of hypothesis approach is followed to ensure the weapon system meets the claimed accuracy. This means each case under consideration may require a different number of weapon releases to establish the correctness of the estimation" (NATO AGARD Vol 10, "Weapons Delivery Analysis and Ballistic Flight Testing," pg 80-81).
Sincerely,
Mark "SCIPR" Jones Jr.
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