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GNSS HAT Library Documentation
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  1. GNSS HAT Library Documentation
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  5. Hot Start

Hot Start

Benchmark cold start vs hot start acquisition times.

Source: examples/cpp/hot-start/, examples/c/hot-start/, examples/python/hot_start.py

What It Does

  1. Cold start — hardResetUbloxSom_ColdStart() clears all satellite data, measures time to first fix
  2. Hot start — softResetUbloxSom_HotStart() preserves satellite data, measures time to first fix

Expected Results

Reset TypeTypical TTFFDescription
Cold start30–60 secondsNo satellite data — receiver must search and acquire
Hot start1–3 secondsPreserved ephemeris/almanac enables rapid reacquisition
Note
Hot start is much faster because the receiver already knows which satellites are visible. Always use softResetUbloxSom_HotStart() unless you specifically need to clear stored data.

Running

sudo examples/bin/hot-start

sudo build/examples/c/hot-start/hot-start

python3 examples/python/hot_start.py