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Comment by simonjgreen | Hacker News Reader

I for one absolutely recall "classic" GNSS based purely on GPS. The combination of only having GPS, early slow hardware with only cold starts, young software implementations, made for quite a ropey experience.

I think my first proper experience was a PCMCIA GPS card in an HP IPaq running TomTom 2, or possibly some Garmin version. Revolutionary at the time, and brilliant on long journeys, but compared to today it was awful.

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I still have an old Garmin for sea kayaking that I sometimes use. With a completely clear view of the sky it can easily take quite a few minutes to get a fix.

This is actually how all gps devices still work, including the latest smartphones and watches. It's just that now, devices can pre-download the almanac over your data connection, mostly eliminating that delay.

Well most offline devices don't take minutes now except for the first fix in a long time. It's generally around 30 seconds to a minute.

Usually the almanac is stored in non-volatile memory so additional startup fixes are much faster.

It's more than that too, old receivers couldn't track and download from as many satellites at once. All modern receivers can pull almanac/ephemeris data from pretty much everything they see at once now.

I've got an eMap - last time I tried it (after it was off for N years), it took upwards of 20 minutes to get a fix with a clear sky because it could only track (AFAIK) 6 satellites and without the hints from recent use, it struggled badly.

But there was another big important to positioning: Incorporating other signals (cell & WiFi). There's a huge difference on the same Android device with and without Google services (which do the aforementioned job).

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