That is bullshit. ~7 yeras ago I worked at a company, which designed and manufactured GNSS receivers capable of receiving gps,glonass,gallileo,qzss and blend the signals to get more accurate solution. Receivers started at $5000 a pop though.

The company had no problems selling in the US abd Russia. And even had multiple competitors.

Hence, expert/import laws are not a problem. At least for professional equipment.

Nowadays, combined GNSS receivers like you mention are available from various electronic retailers for around 20-50$ a piece. The uBlox Neo M8 is a popular chip, there are a few others too. They are widely used in UAVs (where I know them from) and a variety of other applications, and routinely use anywhere between 22-28 active satellites from multiple constellations (compared to typical 7-11 visible for GPS alone).

P.S.: the tech was around at least a decade ago. Nowadays you can have at least alternating mode in cheap consumer devices.

NFI. My iPhone 6s (a few years old) includes "Assisted GPS, GLONASS, Galileo, and QZSS" [0] and I suspect that most other modern mobile phones do as well.

Besides, I would consider relying totally on any one country's GNSS (especially when several are available at very little additional cost) to be a rather poor decision.

[0]: https://support.apple.com/kb/SP726?locale=en_US

I use a lower end phone (250ish dollars) that has (at least) both GPS and glonass.

GPS+GLONASS chips have been available for a while now. Here’s an article about some new chips which support 4 constellations: https://www.gpsworld.com/quad-constellation-receiver-gps-glo...

Since most smartphones today work at least with GPS and GLONASS, what does happen, if just one signal for ex. the GPS signal is spoofed / faked?

I suspect it has something to do with the potential for a chip to be classified as USML Cat XII(d) under ITAR, more specifically, "specially designed for use with a null steering antenna, an electronically steerable antenna, or including a nullsteering antenna designed to reduce or avoid jamming signal"[1].

The actual USML[2] is a bit...verbose.

[1] http://insidegnss.com/u-s-eases-export-regulations-for-gps-r...

[2] https://www.ecfr.gov/cgi-bin/text-idx?node=pt22.1.121#se22.1...

Yes this seems strange, I can only assume that it means the devices will still function accurately despite any US GPS degradation (eg around military installations, sensitive events etc), ie they will no longer be under US control.

But that would apply whether they are multi-system capable, or just that they can read the other systems, and are not entirely dependent on GPS.

The national security laws prevent chips from working if you're above a certain height and over a certain speed. Although most chips implement an "or" instead of an "and".

As for military receivers, apparently they are unclassified but plug into a separate system that works like a TPM and provides the decryption keys, which have to be refreshed at least once a year.