Multilateration authorised in US
The US Federal Communications Commission (FCC) has cleared the NextNav indoor nav system for use throughout the USA.
The FCC has issued Multilateration Location and Monitoring Service (M-LMS) licenses enabling NextNav to start commercial operation of its advanced positioning network, designed primarily to support '911' (999 or 112) emergency services.
NextNav has been testing a fully-deployed trial network in the San Francisco Bay Area for over 3 years.
The terrestrial positioning network is designed to complement GPS in urban areas and inside buildings, where GPS is significantly degraded or denied due to loss of GNSS signals.
The FCC found that NextNav’s system delivered better accuracy then existing technologies in indoor urban environments, and was the only technology tested capable of providing floor-level height accuracy.
The system uses multilateration - precisely located and synchronised transmitters emit pulses at frequencies and power levels similar to mobile phone usage and pulse times-of-arrival yield position in a similar way to Loran.
Accuracy is cited as horizontal accuracy (50%) of 20m and vertical accuracy, using differential pressure, 2m. Time to first fix is ~5s.
Details from NextNav below.