
Thomas Watson contributed to the ArduPilot/ardupilot repository by developing and refining core features for embedded flight control systems, focusing on reliability, memory optimization, and cross-platform consistency. He engineered improvements in navigation algorithms, scripting safety, and build automation, using C++ and Python to modernize codebases and streamline CI pipelines. His work included enhancing sensor fusion in EKF modules, optimizing memory usage for resource-constrained hardware, and strengthening scripting interfaces with Lua integration. By addressing critical bugs and improving test coverage, Thomas delivered robust solutions that improved system stability, reduced maintenance overhead, and enabled safer, more predictable autonomous vehicle deployments across diverse hardware platforms.

February 2026 monthly summary for ArduPilot/ardupilot: delivered targeted enhancements for ESP32 board support and fixed a critical EKF3 covariance zeroing issue in ground tilt scenarios, delivering tangible improvements in reliability, navigation robustness, and ground control communication.
February 2026 monthly summary for ArduPilot/ardupilot: delivered targeted enhancements for ESP32 board support and fixed a critical EKF3 covariance zeroing issue in ground tilt scenarios, delivering tangible improvements in reliability, navigation robustness, and ground control communication.
January 2026 (2026-01) monthly summary for ArduPilot/ardupilot focused on UX consistency, memory efficiency, and stability across multiple vehicle types, delivering tangible business value for pilots and developers. Key features delivered: - QGroundControl mode name improvements across ArduCopter, ArduPlane, ArduSub, Rover, and Blimp to standardize UX and reduce pilot confusion. Commits include: ArduCopter: 56ba113f0bacd688a30ecfc004d5a04e082f5031; ArduPlane: d7a4954310efc34457322af2e35c19668a9c2f37; ArduSub: 0cabab2a99334cb54f854c9b93d59e155a2ce057; Rover: bb0e87ae1c0ecea8f501b14c70fd2b416659461e; Blimp: adbf16ff1651f41b9c1fc0d9a852273b90535032. - ArduSub: remove unnecessary namespace qualifier to simplify maintenance and readability. Commit: 38fd12ec9c5ca5f4b7d3d65fbf755efe0cb67c19. - AP_NavEKF memory optimizations across NavEKF2/3 to reduce RAM usage by reusing RAM, moving nextP arrays, and removing redundant allocations. Commits include: 461e6ce3871e2b6fe862109a6c2f16c5ca8bc632; fc0516da0ce9631e6952e0933c41da1e1f3eca35; c472d13a2fe4713961e86259708f65e433097769; 1da52f824ab2698f25be8aae24767073d0b1f2df; 04cf6486e8d42ce138de816e8466244346ed77cb. - AP_NavEKF3: Mag declination fusion implemented in Python with generated FuseDeclination code, aligning variable naming and removing redundant checks. Commits include: 8fa0e87de36fadb1fe8c844049779096acc06457; c3d32ceb95adfb2b8a9b08b03a495d6b73323dbf; b7df9c04d2eb3720a2812e37f3145bd7ab65bebd; 6c1fb03069f9b97b18f4c2b2eb07dcae48aa3a24. - Autotest: Copter Replay tests enhancements, including resetting throttle between Copter Replay tests and adding a Copter EKF Replay wind/airspeed subtest. Commits: 4c4f426ecbabf2de13db90f95ee51da3937ff0ea; 3b7558acb85a617e75b1baaf0a074cf562396a5d. Major bugs fixed: - ArduCopter: fix altitude truncation in RTL descent and fix roll truncation in level determination. Commits: 042ae97d016f8ad3ee2b57d7dae64a3eec11c1b6; 0612b9d15d16937b267e94f7591d64d08389f14e. - AP_Param: workaround for Clang -ftrapping-math to maintain stable builds. Commit: d70cefdb908596531b992b7877a89622d6eec6a1. - ArduPilot waf: globally ignore invalid-offsetof warning to maintain clean builds. Commit: 8c3b38655a4962cc858d14335482afe0726644c2. - DroneCAN: update to fix Python compatibility issues in newer environments. Commit: ea57608b322a2652880b2131d19449b88d1f1ec5. - AP_Scripting: fix minor bug in repl applet. Commit: 56005f8ca8b299409ca7049b8326f3a0892ae6d8. Overall impact and accomplishments: - Delivered UX improvements, memory efficiency, and stability across multiple platforms, enabling safer operations, faster testing cycles, and more predictable deployments. The changes reduce pilot confusion, evaluate EKF performance under constrained memory, and stabilize builds across CI environments. Technologies/skills demonstrated: - C/C++ embedded flight software, Kalman filtering and sensor fusion, Python-based code generation, memory optimization techniques, and CI/build hygiene.
January 2026 (2026-01) monthly summary for ArduPilot/ardupilot focused on UX consistency, memory efficiency, and stability across multiple vehicle types, delivering tangible business value for pilots and developers. Key features delivered: - QGroundControl mode name improvements across ArduCopter, ArduPlane, ArduSub, Rover, and Blimp to standardize UX and reduce pilot confusion. Commits include: ArduCopter: 56ba113f0bacd688a30ecfc004d5a04e082f5031; ArduPlane: d7a4954310efc34457322af2e35c19668a9c2f37; ArduSub: 0cabab2a99334cb54f854c9b93d59e155a2ce057; Rover: bb0e87ae1c0ecea8f501b14c70fd2b416659461e; Blimp: adbf16ff1651f41b9c1fc0d9a852273b90535032. - ArduSub: remove unnecessary namespace qualifier to simplify maintenance and readability. Commit: 38fd12ec9c5ca5f4b7d3d65fbf755efe0cb67c19. - AP_NavEKF memory optimizations across NavEKF2/3 to reduce RAM usage by reusing RAM, moving nextP arrays, and removing redundant allocations. Commits include: 461e6ce3871e2b6fe862109a6c2f16c5ca8bc632; fc0516da0ce9631e6952e0933c41da1e1f3eca35; c472d13a2fe4713961e86259708f65e433097769; 1da52f824ab2698f25be8aae24767073d0b1f2df; 04cf6486e8d42ce138de816e8466244346ed77cb. - AP_NavEKF3: Mag declination fusion implemented in Python with generated FuseDeclination code, aligning variable naming and removing redundant checks. Commits include: 8fa0e87de36fadb1fe8c844049779096acc06457; c3d32ceb95adfb2b8a9b08b03a495d6b73323dbf; b7df9c04d2eb3720a2812e37f3145bd7ab65bebd; 6c1fb03069f9b97b18f4c2b2eb07dcae48aa3a24. - Autotest: Copter Replay tests enhancements, including resetting throttle between Copter Replay tests and adding a Copter EKF Replay wind/airspeed subtest. Commits: 4c4f426ecbabf2de13db90f95ee51da3937ff0ea; 3b7558acb85a617e75b1baaf0a074cf562396a5d. Major bugs fixed: - ArduCopter: fix altitude truncation in RTL descent and fix roll truncation in level determination. Commits: 042ae97d016f8ad3ee2b57d7dae64a3eec11c1b6; 0612b9d15d16937b267e94f7591d64d08389f14e. - AP_Param: workaround for Clang -ftrapping-math to maintain stable builds. Commit: d70cefdb908596531b992b7877a89622d6eec6a1. - ArduPilot waf: globally ignore invalid-offsetof warning to maintain clean builds. Commit: 8c3b38655a4962cc858d14335482afe0726644c2. - DroneCAN: update to fix Python compatibility issues in newer environments. Commit: ea57608b322a2652880b2131d19449b88d1f1ec5. - AP_Scripting: fix minor bug in repl applet. Commit: 56005f8ca8b299409ca7049b8326f3a0892ae6d8. Overall impact and accomplishments: - Delivered UX improvements, memory efficiency, and stability across multiple platforms, enabling safer operations, faster testing cycles, and more predictable deployments. The changes reduce pilot confusion, evaluate EKF performance under constrained memory, and stabilize builds across CI environments. Technologies/skills demonstrated: - C/C++ embedded flight software, Kalman filtering and sensor fusion, Python-based code generation, memory optimization techniques, and CI/build hygiene.
2025-12 Monthly Summary for ArduPilot/ardupilot Key features delivered: - Arming safety bypass across platforms: Implemented ARMING_CHECK to ARMING_SKIPCHK across AP_Arming, Blimp, ArduPlane, ArduSub, Rover, and ArduCopter to bypass arming safety checks where appropriate. This involved six platform modules and a series of commits to ensure consistent behavior across the stack. - Scripting and tooling improvements: AP_Scripting enhancements including unified handling of legacy dot vs. colon calls, logger refactor and type-safety improvements, and dynamic code generation for metatables. Also introduced protected-mode scripting execution and related safety hardening (protected mode, removal of Lua panic handler, simplified abort path, and improved error handling to prevent leaks). - Magnetometer and EKF performance improvements: AP_NavEKF3 magnetometer fusion enhancements (skip zero values, KH handling refinements) and inline KH computation to reduce latency. Also comprehensive covariance correction optimizations across FuseAirspeed, FuseSideslip, FuseDragForces, FuseEulerYaw, FuseDeclination, FuseOptFlow, FuseBodyVel, FuseRngBcn, and removal of KH array in common code to save RAM and improve maintainability. - RAM optimization and SITL readiness: SITL frame construction moved to dynamically allocate to save RAM; earlier SITL initialization in AP_HAL_ESP32 to speed up start-up. These changes reduce RAM footprint and improve testability in CI. - HAL and safety-related low-level improvements: Implemented working setjmp in HAL layers (ChibiOS and Cortex-M variants) to ensure stable non-local control flow; updated related build guards and integration points. Major bugs fixed: - AP_Logger: fixed error handling when calculating length of over-long packets to prevent false crash conditions. - AP_Scripting: fixed MAVLink reinit crash with larger script sizes; addressed CRSF leaks and nullptr dereferences in scripting; improved safety in engine load paths to prevent leaks on error. - AP_Compass: removed probing failure message for MMC5XX3 compass to reduce noisy logs and false alarms. - Setjmp safety: replaced legacy setjmp workarounds with proper ap_setjmp usage and added build-time guards to enforce correct usage on ChibiOS. - Replay tooling: fixed syntax warning and added build clean/debug options for more robust replay checks. Overall impact and accomplishments: - Improved safety, reliability, and maintainability of the flight stack with cross-platform consistency (ARMing behavior, scripting safety, and setjmp correctness). - Substantial performance and memory improvements in NavEKF3 and associated sensors fusion, enabling faster and more accurate state estimation on resource-constrained platforms. - Faster iteration and testing through improved SITL initialization and RAM optimization, reducing runtime overhead and CI resource usage. - Strong foundation for safer user scripting and logging, with more robust error handling and reduced log noise. Technologies/skills demonstrated: - C/C++ embedded development, cross-platform (AP_Arming, AP_Scripting, AP_HAL_ChibiOS, AP_HAL Cortex-M) - Real-time control and state estimation: NavEKF3, magnetometer fusion, covariance corrections - Memory optimization and safe programming practices: KH array management, dynamic SITL framing, protected-mode scripting, setjmp handling - Code generation and metatable design for scripting engine; rigorous error handling and safety hardening - Testing and tooling improvements: CI-friendly SITL readiness, replay tooling improvements
2025-12 Monthly Summary for ArduPilot/ardupilot Key features delivered: - Arming safety bypass across platforms: Implemented ARMING_CHECK to ARMING_SKIPCHK across AP_Arming, Blimp, ArduPlane, ArduSub, Rover, and ArduCopter to bypass arming safety checks where appropriate. This involved six platform modules and a series of commits to ensure consistent behavior across the stack. - Scripting and tooling improvements: AP_Scripting enhancements including unified handling of legacy dot vs. colon calls, logger refactor and type-safety improvements, and dynamic code generation for metatables. Also introduced protected-mode scripting execution and related safety hardening (protected mode, removal of Lua panic handler, simplified abort path, and improved error handling to prevent leaks). - Magnetometer and EKF performance improvements: AP_NavEKF3 magnetometer fusion enhancements (skip zero values, KH handling refinements) and inline KH computation to reduce latency. Also comprehensive covariance correction optimizations across FuseAirspeed, FuseSideslip, FuseDragForces, FuseEulerYaw, FuseDeclination, FuseOptFlow, FuseBodyVel, FuseRngBcn, and removal of KH array in common code to save RAM and improve maintainability. - RAM optimization and SITL readiness: SITL frame construction moved to dynamically allocate to save RAM; earlier SITL initialization in AP_HAL_ESP32 to speed up start-up. These changes reduce RAM footprint and improve testability in CI. - HAL and safety-related low-level improvements: Implemented working setjmp in HAL layers (ChibiOS and Cortex-M variants) to ensure stable non-local control flow; updated related build guards and integration points. Major bugs fixed: - AP_Logger: fixed error handling when calculating length of over-long packets to prevent false crash conditions. - AP_Scripting: fixed MAVLink reinit crash with larger script sizes; addressed CRSF leaks and nullptr dereferences in scripting; improved safety in engine load paths to prevent leaks on error. - AP_Compass: removed probing failure message for MMC5XX3 compass to reduce noisy logs and false alarms. - Setjmp safety: replaced legacy setjmp workarounds with proper ap_setjmp usage and added build-time guards to enforce correct usage on ChibiOS. - Replay tooling: fixed syntax warning and added build clean/debug options for more robust replay checks. Overall impact and accomplishments: - Improved safety, reliability, and maintainability of the flight stack with cross-platform consistency (ARMing behavior, scripting safety, and setjmp correctness). - Substantial performance and memory improvements in NavEKF3 and associated sensors fusion, enabling faster and more accurate state estimation on resource-constrained platforms. - Faster iteration and testing through improved SITL initialization and RAM optimization, reducing runtime overhead and CI resource usage. - Strong foundation for safer user scripting and logging, with more robust error handling and reduced log noise. Technologies/skills demonstrated: - C/C++ embedded development, cross-platform (AP_Arming, AP_Scripting, AP_HAL_ChibiOS, AP_HAL Cortex-M) - Real-time control and state estimation: NavEKF3, magnetometer fusion, covariance corrections - Memory optimization and safe programming practices: KH array management, dynamic SITL framing, protected-mode scripting, setjmp handling - Code generation and metatable design for scripting engine; rigorous error handling and safety hardening - Testing and tooling improvements: CI-friendly SITL readiness, replay tooling improvements
November 2025 (2025-11) monthly performance summary for ArduPilot/ardupilot. The month focused on delivering business-value improvements in build reliability, environment handling, and safer arming flows, while strengthening CI/test robustness and addressing critical bug surfaces. Key outcomes include streamlined build pipelines, more deterministic environments for cross-platform testing, and safer defaults that reduce risk in field deployments.
November 2025 (2025-11) monthly performance summary for ArduPilot/ardupilot. The month focused on delivering business-value improvements in build reliability, environment handling, and safer arming flows, while strengthening CI/test robustness and addressing critical bug surfaces. Key outcomes include streamlined build pipelines, more deterministic environments for cross-platform testing, and safer defaults that reduce risk in field deployments.
October 2025 focused on stabilizing build/deploy workflows, hardening data integrity for critical logging paths, and expanding test robustness to reduce CI variability. Delivered concrete improvements across ArduPilot/ardupilot, emphasizing business value through reliability, faster iteration cycles, and clearer hardware traceability.
October 2025 focused on stabilizing build/deploy workflows, hardening data integrity for critical logging paths, and expanding test robustness to reduce CI variability. Delivered concrete improvements across ArduPilot/ardupilot, emphasizing business value through reliability, faster iteration cycles, and clearer hardware traceability.
Monthly summary for 2025-09 focused on delivering cross-platform stability, code clarity, and build/CI efficiency for ArduPilot/ardupilot, with a set of refactors and HWDEF/BUILD improvements that reduce maintenance burden and accelerate feedback loops.
Monthly summary for 2025-09 focused on delivering cross-platform stability, code clarity, and build/CI efficiency for ArduPilot/ardupilot, with a set of refactors and HWDEF/BUILD improvements that reduce maintenance burden and accelerate feedback loops.
July 2025 performance summary for peterbarker/ardupilot focused on memory management modernization, HAL cleanup, and reliability improvements across HAL targets. The work reduces memory footprint, stabilizes builds, and improves test coverage, enabling safer broader platform adoption and faster CI feedback.
July 2025 performance summary for peterbarker/ardupilot focused on memory management modernization, HAL cleanup, and reliability improvements across HAL targets. The work reduces memory footprint, stabilizes builds, and improves test coverage, enabling safer broader platform adoption and faster CI feedback.
June 2025 performance highlights for the ArduPilot build stack focused on Python ecosystem resilience and startup cleanliness. Delivered concrete improvements that reduce build failures, ease ongoing maintenance, and enable smoother future upgrades. The changes enhance CI reliability and contributor onboarding by ensuring clearer Python version handling and minimizing startup side effects in the ArduPilotWAF pipeline.
June 2025 performance highlights for the ArduPilot build stack focused on Python ecosystem resilience and startup cleanliness. Delivered concrete improvements that reduce build failures, ease ongoing maintenance, and enable smoother future upgrades. The changes enhance CI reliability and contributor onboarding by ensuring clearer Python version handling and minimizing startup side effects in the ArduPilotWAF pipeline.
May 2025 focused on stabilizing STM32H7 hardware and hardening the scripting layer for safer operations. Delivered targeted fixes and robustness improvements that reduce risk, improve error visibility, and enable safer deployments on STM32H7-based boards, while enhancing Lua interactions and error reporting in AP_Scripting.
May 2025 focused on stabilizing STM32H7 hardware and hardening the scripting layer for safer operations. Delivered targeted fixes and robustness improvements that reduce risk, improve error visibility, and enable safer deployments on STM32H7-based boards, while enhancing Lua interactions and error reporting in AP_Scripting.
April 2025 monthly summary — Key feature delivery, reliability improvements, and cross-repo collaboration across ArduPilot and nixpkgs. Focused on parameter safety, GPS interpretation, navigation accuracy, and SITL robustness to deliver tangible business value in safety, reliability, and developer velocity.
April 2025 monthly summary — Key feature delivery, reliability improvements, and cross-repo collaboration across ArduPilot and nixpkgs. Focused on parameter safety, GPS interpretation, navigation accuracy, and SITL robustness to deliver tangible business value in safety, reliability, and developer velocity.
March 2025 accomplishments focused on expanding hardware compatibility, stabilizing flash operations, and modernizing the build/tooling while reducing maintenance burden. Key outcomes include JEDEC NOR support enhancements for LittleFS, bootloader/HAL cleanup, and build-system modernization that enable broader hardware support, more reliable flash handling, and smoother CI.
March 2025 accomplishments focused on expanding hardware compatibility, stabilizing flash operations, and modernizing the build/tooling while reducing maintenance burden. Key outcomes include JEDEC NOR support enhancements for LittleFS, bootloader/HAL cleanup, and build-system modernization that enable broader hardware support, more reliable flash handling, and smoother CI.
February 2025 for peterbarker/ardupilot delivered significant reliability and performance improvements across MAVLink scripting, logging, system I/O, and filesystem backends. Key outcomes include a faster, clearer MAVLink scripting experience with initialization refactors and improved error messaging, a deadlock fix in MAVLink RX initialization, and substantial LittleFS core improvements. The team also introduced a new fsync-optimization API to boost streaming throughput across ESP32, FATFS, and LittleFS, and added configurable I2C timeouts for ESP32 to improve hardware interaction reliability.
February 2025 for peterbarker/ardupilot delivered significant reliability and performance improvements across MAVLink scripting, logging, system I/O, and filesystem backends. Key outcomes include a faster, clearer MAVLink scripting experience with initialization refactors and improved error messaging, a deadlock fix in MAVLink RX initialization, and substantial LittleFS core improvements. The team also introduced a new fsync-optimization API to boost streaming throughput across ESP32, FATFS, and LittleFS, and added configurable I2C timeouts for ESP32 to improve hardware interaction reliability.
Concise monthly summary for 2025-01: peterbarker/ardupilot - Delivered features and stability improvements across ESP32, LittleFS, scripting, and Lua; improved CI reliability; refined build system; and clarified semaphore semantics. Result: more robust, memory-safe ESP32 builds; more reliable CI, faster releases; scripting enablement on KakuteH7Mini-Nand.
Concise monthly summary for 2025-01: peterbarker/ardupilot - Delivered features and stability improvements across ESP32, LittleFS, scripting, and Lua; improved CI reliability; refined build system; and clarified semaphore semantics. Result: more robust, memory-safe ESP32 builds; more reliable CI, faster releases; scripting enablement on KakuteH7Mini-Nand.
Month: 2024-12. Focused delivery in ArduPilot/ardupilot on feature improvements and critical bug fixes that enhance sensor fidelity, flight safety, build reliability, and maintainability. The work strengthens tests, safety controls, and parameter metadata, delivering business value through more reliable simulations, safer auto-tuning, streamlined builds, and centralized documentation.
Month: 2024-12. Focused delivery in ArduPilot/ardupilot on feature improvements and critical bug fixes that enhance sensor fidelity, flight safety, build reliability, and maintainability. The work strengthens tests, safety controls, and parameter metadata, delivering business value through more reliable simulations, safer auto-tuning, streamlined builds, and centralized documentation.
In 2024-11, delivered key features and bug fixes in ArduPilot/ardupilot with a focus on sensor subsystems, power management, and test robustness. Key features delivered include cross-module DroneCAN subscription optimization across OpticalFlow, Mount, GPS, Proximity, EFI, Compass, RangeFinder, and additional modules, reducing redundant null checks and simplifying error handling to improve efficiency and robustness; INA3221 Battery Monitor Driver Refactor delivering improved configuration, channel management, data reading accuracy, dynamic channel enabling, health tracking, and energy accounting (mAh/Wh); MAVLink autotest enhancements enabling assertions on individual elements within message arrays for granular testing; and a bug fix addressing a Lua logger warning in ESC_slew_rate example. These changes collectively reduce CPU load, increase data reliability, and enhance test coverage across the project.
In 2024-11, delivered key features and bug fixes in ArduPilot/ardupilot with a focus on sensor subsystems, power management, and test robustness. Key features delivered include cross-module DroneCAN subscription optimization across OpticalFlow, Mount, GPS, Proximity, EFI, Compass, RangeFinder, and additional modules, reducing redundant null checks and simplifying error handling to improve efficiency and robustness; INA3221 Battery Monitor Driver Refactor delivering improved configuration, channel management, data reading accuracy, dynamic channel enabling, health tracking, and energy accounting (mAh/Wh); MAVLink autotest enhancements enabling assertions on individual elements within message arrays for granular testing; and a bug fix addressing a Lua logger warning in ESC_slew_rate example. These changes collectively reduce CPU load, increase data reliability, and enhance test coverage across the project.
October 2024: DJIRS2 Mount Driver Improvements for ArduPilot/ardupilot delivered reliability enhancements, efficient CAN packet handling, and multi-bus/configurability. Included re-enabled Lua checks and correctness fixes in gimbal control, refactored CAN packet filtering for relevance, and added configurable support for different CAN buses and mount instances with clearer usage/docs. Changes tracked across commits afcc722995c61ac83f92d9407ee51ba1087e80bd; 1f0dff0178d179bb2b9c1c21d79cb582b9ba0189; dd270dac2ef76db2a244e70b779372bcf774167e.
October 2024: DJIRS2 Mount Driver Improvements for ArduPilot/ardupilot delivered reliability enhancements, efficient CAN packet handling, and multi-bus/configurability. Included re-enabled Lua checks and correctness fixes in gimbal control, refactored CAN packet filtering for relevance, and added configurable support for different CAN buses and mount instances with clearer usage/docs. Changes tracked across commits afcc722995c61ac83f92d9407ee51ba1087e80bd; 1f0dff0178d179bb2b9c1c21d79cb582b9ba0189; dd270dac2ef76db2a244e70b779372bcf774167e.
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