Design notes
Overview
Working notes on why things are shaped the way they are: what was tried, what was measured, and what the hardware turned out to do. They keep their numbers and dates, and they are not maintained as manuals. When a page in Apps, Nodes, Tools or Libraries needs the history behind a decision, it links here.
| Note | What it covers | Reader-facing pages |
|---|---|---|
| CarPlay port | The port from LIVI, the USB transport, usbmux and lockdown, iAP2 and the MFi coprocessor, video, touch, audio, hardware sessions, and what is still unverified. | carplay |
| Map renderer | Why the renderer is ours, how it draws, the pitched camera, labels, the tile cache, and what a frame costs. | map_server, map_render |
| Map build | Why it replaced tilemaker, the one classification table, memory, the tiler’s geometry traps, identity, and how the routing hierarchy is trusted. | map_build |
| Race tracks | What the source data is, deriving centrelines, the QA gate, and known gaps. | tracks |
| scope internals | The data source seam, panel registration, buffering and seeking, capture, the recorded path, and the per-panel decisions. | scope |
| bag format | The MCAP layout, the two timestamps, drops, and reading a damaged recording. | bag |
| MoTeC UTC protocol | The reverse-engineered protocol, the 0x21 latch, and what has been verified. | can_motec, can_bridge |
| Trimble BD992 notes | ICD gaps, why the parsers are constexpr, and live-hardware findings. | bd992_bridge, gsof |
| Xsens MTi-610 notes | The protocol’s traps, documentation gaps, and what waits on hardware. | mti610_bridge, xbus |
| MOTOTRBO notes | The handshake defects and where the protocol knowledge came from. | xpr_bridge, mototrbo |
| State estimation | Frames, why our own fixed-lag smoother, FEJ, what cannot be observed, time alignment without PPS, GNSS pairing by arrival, the bugs that shaped the code, measured accuracy and NEES, and what is unverified. | state_estimator, estimator_offline |
| csym constant-evaluation limits | What constant evaluation costs on clang and GCC, what was tried, and why csym builds its tape the way it does. | csym |