The Motion GPS is one of the most popular devices within the speed sailing community, but no longer produced:
Inside both devices there is a custom PCB, which includes a u-blox GNSS chip, filters, amplifier, and oscillator. This is different to the ESP-GPS design, which uses a Beitian GNSS module. GNSS modules are packages containing the GNSS chip, antenna, filters, amplifier, and oscillator.
It is worth mentioning that the GNSS oscillator can have a significant impact on accuracy, and it was upgraded when the Motion Mini was re-designed in 2024. The earlier Motion LCD and Motion Mini devices shipped with the u-blox M8, but were subsequently upgraded to the M10.
The UBX-M8030-KT was used by the original Motions, and GNSS modules such as the u-blox MAX M8 + Beitian BN250.
The NEO-M8 datasheet shows the following max navigation update rates, specific to each module:
| Constellations / Services | NEO-M8N | NEO-M8Q |
|---|---|---|
| GPS / GLONASS / BDS B1I / Galileo / BDS B1C | 10 Hz | 18 Hz |
| GPS + GLONASS (default) | 5 Hz | 10 Hz |
These figures are all on the basis of a minimum 98% fix rate under typical conditions, not 100%.
The original Motions (M8) supported logging rates of 1, 2, 5, and 10 Hz:
The M8 itself limited the Motion to just 2 systems when logging at 10Hz, just like the NEO-M8Q.
GPS + GLONASS may have been used for 10 Hz, since that combination was the default for the M8.
The number of satellites was probably limited to avoid Dropped Frames, and maybe to conserve battery.
The UBX-M10050-KB was used by the newer Motions, and GNSS modules such as the u-blox MAX M10 + Beitian BE250.
It is worth noting that the MAX-M10 performance looks very similar to the MAX-M8, but it is nothing like the M9:
The MAX-M10 datasheet shows the following max navigation update rates:
| Constellations / Services | Default Performance | High Performance |
|---|---|---|
| GPS / GLONASS / BDS B1I / Galileo / BDS B1C | 18 Hz | 25 Hz |
| GPS + Galileo (default) | 10 Hz | 20 Hz |
| GPS + Galileo + BeiDou B1C | 8 Hz | 16 Hz |
| GPS + Galileo + GLONASS | 6 Hz | 16 Hz |
| GPS + Galileo + BeiDou B1I | 3 Hz | 12 Hz |
| GPS + Galileo + BeiDou B1C + GLONASS | 4 Hz | 10 Hz |
These figures are all on the basis of a minimum 98% fix rate under typical conditions, not 100%.
The newer Motions (M10) support logging rates of 1, 2, 5, and 10 Hz:
These rates are the same as the M8 devices, but the M10 required some additional configuration:
Final thoughts:
Julien in 2022:
I use the flagship M8030 and add my own filters, amplifier, and oscillator because it’s much better bang for the bucks. All M8 products derive from it or from its die. Achieving the specifications uBlox datasheets boast require better components than what their modules provide, except maybe for the timing series. I also give all these the energy they need.
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