ISO/IEC 24730-62:2013 defines the air-interface for real time locating
systems (RTLS) using a physical layer Ultra Wide Band (UWB) signalling mechanism
(based on IEEE 802.15.4a UWB). This modulation scheme employs high rate pulse
repetition frequencies (PRF) 16 MHz or 64 MHz, and a combination of burst
position modulation (BPM) and binary phase-shift keying (BPSK) giving an
extremely high level of performance with a fully coherent receiver.

In addition to defining the air interface protocol (AIP) in terms of the
physical layer modulation, ISO/IEC 24730-62:2013 also defines the AIP in terms
of the messages sent over the air. This AIP supports simple one-way
communication of a basic blink that may be used for a one-way Time Difference of
Arrival (TDOA) based RTLS, where mobile tags periodically transmit the blink
message which is received by an infrastructure consisting of a number of fixed
reader nodes.

This AIP also optionally supports bidirectional communication and two-way
ranging between the readers and tags of an RTLS. The support of two-way ranging
depends on additionally including a UWB receiver in the tag and UWB transmitters
in the reader infrastructure.

The mandatory default operational mode ensures interoperability between tags
and infrastructure from various manufacturers, while the availability of several
options offers flexibility to the developer of the infrastructure to adapt the
behaviour of the overall system to the specific needs of his
application.