By stripping down LPS v1.1 to a minimum, adding more advanced sensors (accelerometer, gyro, magnetometer and altimeter instead of just an accelerometer) and a LiPo charger, LPS Mini was born! It is hard making a much smaller board without compromising antenna performance. A nice little feature is that the entire board fits in a board edge connector making it possible to access all the I/O present on LPS v1.1 and ordinary Arduino Nano!

Schematic, assembly drawing and BOM:

http://www.loligo.se/navigation/LPS_mini_v1.0_150423.pdf

PCB animation:

http://www.loligo.se/navigation/LPS_mini_v1.0.WMV

Step by step transformation from LPS to LPS Mini:

http://www.loligo.se/LPS_mini/

The two pictures below depict the development steps from RadioBeacon v1.0 via LPS v1.1 to LPS Mini v1.0:

With help of the sensors in LPS Mini, inertial navigation can be done to improve performance. But again, the processing power of ATmega328P is not enough to do that job all by itself. Data must be sent either via UART/I2C or radio (piggyback data on measurement data packages) to an external CPU to do triangulation etc. In our case we use Raspberry Pi for all superior tasks and it works very well! An added benefit is the ability to do firmware upgrades from Raspberry Pi using the LPS boot loader.

LPS and LPS Mini are compatible. LPS boards can use LPS Mini as anchor/tag and the other way around. Except a different set of sensors the main difference is that LPS use 5V I/O level and runs at 16 MHz, while LPS Mini got 3.3V I/O and runs at 8 MHz.