Fix ecef2lla altitude conversion

[glenn-jocher]

Fixes #20.

This corrects the WGS84 eccentricity terms in transformations/ecef2lla.m so latitude and altitude use the same formulation as the referenced implementation.

Validation:

• Round-tripped known WGS84 LLA/ECEF samples in Python against the MATLAB formula; old formula was tens of kilometers low in altitude, corrected formula returns near-zero altitude error.

Deleted: incorrect extra squaring of first and second eccentricity terms in ecef2lla.m.

🛠️ PR Summary

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🌟 Summary

Improves the accuracy of ECEF-to-LLA coordinate conversion by correcting eccentricity calculations in ecef2lla.m 🌍

📊 Key Changes

• Defines the WGS84 eccentricity e separately, then computes squared eccentricity es from it ✅
• Corrects the second eccentricity calculation ep to use the square root as expected 📐
• Fixes the latitude calculation to use es instead of es^2, preventing incorrect scaling in the denominator 🛠️

🎯 Purpose & Impact

• Improves geospatial conversion accuracy for latitude, longitude, and altitude outputs 🎯
• Reduces potential positioning errors when converting Earth-Centered, Earth-Fixed coordinates to latitude/longitude/altitude 🛰️
• Benefits users relying on MATLAB transformations for navigation, mapping, robotics, aerospace, or GPS-related workflows 🚀

[UltralyticsAssistant]

👋 Hello @glenn-jocher, thank you for submitting a ultralytics/functions-matlab 🚀 PR! This automated message is here to help with the review process, and an Ultralytics engineer will assist you soon. Since this PR fixes ECEF-to-LLA altitude conversion logic, please review the checklist below to help ensure a smooth merge:

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[UltralyticsAssistant]

🔍 PR Review

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The PR is clean. The updated WGS84 eccentricity handling in ecef2lla.m matches the standard ECEF-to-LLA formulation, and I did not find any verified regressions or actionable issues in the changed lines.

[UltralyticsAssistant]

🚀 Merged — thank you @glenn-jocher!

“Measure what is measurable, and make measurable what is not so.” — Galileo Galilei

This update brings that spirit to ecef2lla.m by improving the precision of ECEF-to-LLA coordinate conversion through corrected WGS84 eccentricity handling and latitude computation. These refinements help ensure more reliable geospatial outputs for navigation, mapping, robotics, aerospace, and GPS-related MATLAB workflows.

Your contribution strengthens the accuracy and trustworthiness of this function for everyone building on Ultralytics tools. Much appreciated!