Every departure deserves a thoughtful plan.

• I

  Precise prediction

  Cairn — our in-house mountain-hiking timing algorithm — factors in terrain elevation and surface conditions to give accurate estimates of time and effort. Route planning becomes science, not just instinct.

  Cairn · Terrain · Surface

• II

  Full perception

  Elevation profile clearly shows ascent and descent across the whole route. 3D visualization gives an immersive preview of the contours. Slope statistics flag the steep sections — feel the shape of the mountain before you set out.

  Elevation · 3D · Slope

• III

  Real-time companion

  Navigation that stays with you, with timely off-route alerts. Real-time recording of every step. Live Activity keeps key information on the lock screen — just glance and see.

  Navigation · Off-route · Live Activity

• IV

  Record it your way

  Save routes you love, keep a hiking journal, build your trail history. Every departure opens a new story. Every return, a new starting line.

  Saved · Journal · Achievements

The precision of trip estimation comes down to a few engineering details.

I

Cairn — our in-house mountain-hiking timing algorithm

Named after the stone piles climbers stack to mark a reliable route for those who follow. Cairn is tuned for real-world mountain conditions — taking into account slope, ground surface and terrain undulation, with reasonable adjustments for steep descents, so estimates stay close to how the trail actually feels.

Cairn · Slope · Surface · Terrain

II

Elevation hysteresis filter

GPS elevation carries high-frequency noise — naively accumulating raw values would severely inflate ascent. A hysteresis filter ignores small jitter and only confirms an ascent or descent when the change is meaningful — so cumulative ascent reflects what was actually climbed.

Hysteresis · Jitter rejection · True ascent

III

Haversine great-circle distance

The real horizontal distance between two GPS coordinates is not a straight line — it follows a great-circle arc on the Earth's surface. TrailMate uses the Haversine formula for precise horizontal distance, then layers elevation difference separately for slope — distance and ascent are computed independently.

Coordinates · Great circle · Earth curvature

IV

Real-time off-route detection

During recording and navigation, the engine continuously measures how far the current location strays from the preset route — when it goes beyond range, an off-route alert fires. A track buffer is maintained in parallel; when the trip ends, it is compared against the original route to produce a journey report.

Off-route alert · Track buffer · Journey report