A software thing I built: GPS on a 25MHz 486-SX

A developer describes building a real-time GPS-style moving-map display in the early 1990s that ran on severely constrained hardware: a 25 MHz 486-SX (no math co-processor), 32 MB of RAM, ROM-resident software, and a 1024x768 color screen. Instead of traditional floating-point-heavy geodesy and trigonometry, the implementation used the Hipparchus approach based on Voronoi cells, which reduced most computations to 8- and 16-bit integer arithmetic with only one or two single-precision floating-point operations. That method proved surprisingly accurate - claimed to exceed extended-precision floating-point in resolution - and enabled a working prototype that refreshed the display every two seconds on that limited CPU.

The developer sold the client a copy of the Hipparchus library and delivered a fully working model, but contractual/IP constraints forced him to turn everything over; a later contact indicated commercial potential that he could not pursue. The project predated consumer GPS devices by several years (work around 1993) and reportedly outperformed early Garmin/Magellan units, which had small 360x240 monochrome screens and much slower update performance. He notes that a clean-room approach might have preserved ownership, implying the effort was a technologically ahead-of-its-time mapping solution that was limited only by business and IP circumstances.