[joecool1029]

It helps, it's not extremely crucial. There are other methods that don't require the handset's cooperation:

- https://www.mpirical.com/glossary/lmu-location-measurement-u...

- https://www.etsi.org/deliver/etsi_ts/136100_136199/136111/11...

[stingrae]

all these methods aren't super reliable. The combination of all of them is required for what people have come to expect from GPS.