See the C93-M8E application example, which in addition to the evaluation kit can be used to evaluate Untethered Dead Reckoning functionality.

The NEO-M8U module introduces u‑blox’s Untethered Dead Reckoning (UDR) technology, which provides continuous navigation without requiring speed information from the vehicle. This innovative technology brings the benefits of dead reckoning to installations previously restricted to using GNSS alone and significantly reduces the cost of installation for after-market dead reckoning applications.
The strength of UDR is particularly apparent under poor signal conditions, where it brings continuous positioning in urban environments, even to devices with antennas installed within the vehicle. Useful positioning performance is also available during complete signal loss, for example in parking garages and short tunnels. With UDR, positioning starts as soon as power is applied to the module, before the first GNSS fix is available.
The NEO-M8U may be installed in any position within the vehicle without configuration. In addition to its freedom from any electrical connection to the vehicle, the on-board accelerometer and gyroscope sensors result in a fully self-contained solution, perfect for rapid product development with reliable and consistent performance.
The intelligent combination of GNSS and sensor measurements enables accurate, real-time positioning at rates up to 20 Hz, as needed for smooth and responsive interactive applications. Native high rate sensor data is made available to host applications such as driving behaviour analysis or accident reconstruction.
The NEO-M8U includes u‑blox’s latest generation GNSS receiver, which adds Galileo to the multi-constellation reception that already includes GPS, GLONASS, BeiDou and QZSS. The module provides high sensitivity and fast GNSS signal
acquisition and tracking. UART, USB, DDC (I2C compliant) and SPI interface options provide flexible connectivity and enable simple integration with most u‑blox cellular modules.
u‑blox M8 modules use GNSS chips qualified according to AEC‑Q100 and are manufactured in ISO/TS 16949 certified sites. Qualification tests are performed as stipulated in the ISO16750 standard: “Road vehicles – Environmental conditions and testing for electrical and electronic equipment”.