Pro's:
1) Provides SPS accuracy (~3.5m) at extremely low power consumption (<7mA in energy-saving mode).
2) Small form factor (4mmx4mm) could potentially replace the GPS UART header with some clever board re-work - built-in UART interface in chip means relatively easy integration into existing GPS data traces.
3) When used with companion RTC chip, provides accurate long-term date/time retention for firmware use.
4) Adds GNSS logging function when used with external storage (SD card).
5) Provides odometer function which can be accessed by a firmware modification to allow "distance traveled" tracking.
6) Some signal processing hardening against GNSS interference/spoofing.
7) Multi-system compatibility (US GPS, GLONASS, Galileo, etc.) for international applicability.
8) Autonomous GNSS ephemeris downlink/storage (3 days w/ onboard ROM or 6 days w/ external storage (SD card) - enables fast starts from power-off or standby state.
9) Compatible with some position enhancing services (SBAS, D-GPS, etc.)
Con's:
1) Cost ($29 USD/per when purchased in 1 qty or $14 USD/per when purchased in 1000+ qty from DigiKey as of 12/28/21).
2) Requires GNSS antenna integration solution either on the mainboard (performance & space limitations) or into mainboard case (requires external case engineering + GPS antenna port added to main board).
3) ZOE-M8B has no PPS output for precise timing applications (frequency agile/hopping waveforms). Other chips may be substituted which provide PPS output, but potentially at a larger real-estate cost on the board.
Considerations for adding on-board GNSS via a small GNSS SiP chip like the u-blox ZOE-M8B:
u-blox ZOE-M8B Datasheet
Pro's: 1) Provides SPS accuracy (~3.5m) at extremely low power consumption (<7mA in energy-saving mode). 2) Small form factor (4mmx4mm) could potentially replace the GPS UART header with some clever board re-work - built-in UART interface in chip means relatively easy integration into existing GPS data traces. 3) When used with companion RTC chip, provides accurate long-term date/time retention for firmware use. 4) Adds GNSS logging function when used with external storage (SD card). 5) Provides odometer function which can be accessed by a firmware modification to allow "distance traveled" tracking. 6) Some signal processing hardening against GNSS interference/spoofing. 7) Multi-system compatibility (US GPS, GLONASS, Galileo, etc.) for international applicability. 8) Autonomous GNSS ephemeris downlink/storage (3 days w/ onboard ROM or 6 days w/ external storage (SD card) - enables fast starts from power-off or standby state. 9) Compatible with some position enhancing services (SBAS, D-GPS, etc.)
Con's: 1) Cost ($29 USD/per when purchased in 1 qty or $14 USD/per when purchased in 1000+ qty from DigiKey as of 12/28/21). 2) Requires GNSS antenna integration solution either on the mainboard (performance & space limitations) or into mainboard case (requires external case engineering + GPS antenna port added to main board). 3) ZOE-M8B has no PPS output for precise timing applications (frequency agile/hopping waveforms). Other chips may be substituted which provide PPS output, but potentially at a larger real-estate cost on the board.
Thoughts?