They need an oscillator to execute their basic function of positioning. Positioning is based on trilateration, i.e., they need to accurately measure the time it takes for a signal from a satellite to reach them as a measure of how far away the satellite is. To allow cost effective (and small) devices, use of low-cost oscillators is possible. To get the accuracy needed for positioning, the low cost oscillators are disciplined by the timing derived from the GNSS signal.
Yes, there is nothing to prevent a manufacturer from using higher-grade/more expensive oscillators to improve positioning accuracy/stability, and time/frequency accuracy/stability (with time being a by-product of the positioning process, see above about trilateration).
Apart from some software and other hardware features specific to timing/frequency receivers, that is what makes specialized time/frequency receivers noticeably more expensive than the âstandard precisionâ (SPG) devices (in that manufacturerâs parlance).
Yes, because it is a timing/frequency receiver. But some sort of reference frequency is anyhow available internally, and the point here is that it is made available externally.
Standard-precision devices do not typically provide a frequency output, except programmable PPS derived from the internal reference frequency.
Yes, that is what the PPS quantization error that those devices report is all about.
Yes, because it is a dedicated timing/frequency device. That functionality can benefit from holdover functionality. It does not make sense in the context of positioning, where various other approaches to deal with, e.g., loss of signal, are used instead, e.g., dead reckoning. And it is due to those features that a dedicated timing/frequency receiver is more expensive than âstandard precisionâ devices.