LiDAR Time-of-Flight with Limb Detection Sets a New Standard in Athletic Timing
A technology comparison for coaches and performance analysts
SplitFast uses a LiDAR (Light Detection and Ranging) Time-of-Flight sensor to continuously map the timing zone in three dimensions. This depth map is processed in real time by limb detection software that identifies and excludes the athlete's arms and legs — which swing unpredictably ahead of and behind the body — and records the split the instant the leading edge of the trunk crosses the timing plane.
This is the correct event. Athletics rules are unambiguous: finish time is determined by the trunk, not the extremities. SplitFast measures exactly that.
A single infrared beam at a fixed height triggers on whatever crosses it first — a swinging arm, a driving knee, the torso, or a trailing foot. Which body part interrupts the beam depends on the athlete's gait phase at the moment of crossing: an essentially random variable. The result is timing data contaminated by noise that has nothing to do with athletic performance, and no mechanism exists to separate it out.
Two beams at two heights offer marginally more coverage but do not solve the core problem. Neither beam can distinguish a limb from the trunk. Two anatomically ambiguous measurements at fixed heights cannot be combined to produce one anatomically correct trunk-crossing time. Dual-beam systems also double the alignment burden and double the points of failure, while inheriting all the weather and sunlight vulnerability of single-beam systems.
Transponder systems require every athlete to wear a device, introducing equipment management overhead and the constant risk of inconsistent mounting. More fundamentally, the transponder is not the trunk: its position relative to the body's leading edge varies with mounting location, posture, and stride phase. Ankle-worn tags measure a limb position outright. These systems serve mass-participation events well, where throughput matters more than precision — but they are ill-suited to performance measurement where every millisecond counts.
| Capability | SplitFast | Dual-Beam | Single-Beam | Transponder |
|---|---|---|---|---|
| Trunk-referenced timing | ✓ | ✗ | ✗ | ~ |
| Limbs excluded from trigger | ✓ | ✗ | ✗ | ✗ |
| Consistent across gait phases | ✓ | ✗ | ✗ | ~ |
| No athlete equipment needed | ✓ | ✓ | ✓ | ✗ |
| No precision alignment required | ✓ | ✗ | ✗ | ✓ |
| Weather and sunlight immune | ✓ | ✗ | ✗ | ~ |
| Consistent across all athlete builds | ✓ | ✗ | ✗ | ~ |
| Rapid field deployment | ✓ | ~ | ✓ | ✗ |
Legend: ✓ = Fully capable | ✗ = Not capable | ~ = Partial or conditional
Single-beam and dual-beam systems trigger on whatever breaks the beam — limbs included. There is no way to extract a trunk-referenced time from them. Transponder systems introduce device dependency and mounting variability that undermine the precision they appear to offer. None of these approaches measures what athletics rules define as the finish.
SplitFast does. By actively mapping the timing zone, identifying and discarding limb data, and recording the moment the trunk's leading edge crosses the plane, SplitFast delivers timing that is anatomically correct, gait-phase independent, weather-proof, and ready to use in seconds. For coaches and analysts who need data they can trust, it is the only system that measures the right thing.