Compared to the FCC, the ETSI rules are more clear, less permissive, but are self certified as is generally the case under ETSI domain.
Short answer: only legal way to operate an ETSI compliant UWB location system outdoors with fixed anchors is EN 302-065-2 LT2, which requires operating in the 3.4 to 4.8 GHz band, and “may” require local registration/authorization for each site.
UWB systems can be operated under two regulations (and links to what I think are current versions):
EN 302-065-1 Generic UWB Applications
EN 302 065-2 UWB Location Tracking
Note that just because a system may do location tracking with UWB signals doesn’t mean it can’t fall under the EN 302 065-1 directive.
The EN 302 065-1 restrictions state:
the UWB transmitter equipment conforming to the present document is not to be installed at a fixed outdoor location, for use in flying models, aircraft and other forms of aviation.
Allowed operation is 6.0 to 8.5 GHz without any mitigation, or 3.1 to 4.8 and 8.5 to 9.0 GHz with mitigation. Only LDC (low duty cycle) mitigation is available on the DW1000 since it cannot do DAA (detect and avoid). LDC limits duty cycle to 0.5% which works for TDoA/multitime style systems in some cases, but often doesn’t work for TWR/multirange style systems unless the capacity is very low.
The EN 302-065-2 restrictions state:
LT1 (6.0 to 8.5 GHz without DAA): Fixed outdoor LT1 transmitters are not permitted.
LT2 (3.4 to 4.8 GHz without DAA): The transmitting terminals in these systems may be located indoors or outdoors, and may be fixed or mobile.
LAES: Not generally useful, special case.
LT1 systems can’t have fixed outdoor transmitters. Exactly what constitutes “fixed” and “outdoor” are subject to some debate, but something like an athletic field or an outdoor stock yard seem clearly excluded.
LT2 seems like the opening for fixed outdoor location systems, but LT2 systems are subject to registration/authorization and local coordination for a specific site which makes them encumbered for general deployment. A further issue is that the lower band is not as generally useful world wide, and support for the lower bands is not indicated yet for future chips.
Under LT1, the directive suggests outdoor systems can be built with receive only fixed anchors. Realistically, a good location system can’t be built this way. Without transmitting anchors, you can’t use TWR/multirange. So that leaves TDoA/multitime algorithms. But for those to work, you have to synchronize the anchors somehow. The best way is to have anchors transmit packets to each other, or to have fixed reference tags, but that isn’t allowed outdoors for LT1.
If you build a wired synchronization system, as suggested in Decawave APS007, or as used in the Zebra Dart system, you run into problems in practice. For one such issue, the time delay in network cables vary with temperature sufficiently to shift accuracy quite a bit. The insulation expands with temperature, changing the capacitance, which changes the delay, among other factors. So the only way to make a truly accurate UWB system is to have transmitters at fixed known locations to reference against, be they other anchors (such as we do) or fixed reference tags (which is what the Dart system does despite having wired sync).
Our Ciholas products are CE marked under EN 302-065-1, the generic UWB directive, and we operate them at 6.5 GHz, channel 5. The manual limits use to indoor operation. Whether customers follow that rule is up to them.
The use case limitations of UWB (outdoor, flying, toys, etc) are really a weird set of rules that are not typical for radio systems, cause a lot of trouble, are not globally harmonized, and don’t have clear enforcement requirements. If I could change anything about UWB, it would be this.
Mike Ciholas, President, Ciholas, Inc
3700 Bell Road, Newburgh, IN 47630 USA
mikec@ciholas.com
+1 812 962 9408