WAM incorporates new
ground station output formats specifically designed for WAM and ADS-B: •
ASTERIX CAT19 for WAM system status • ASTERIX CAT20 for WAM reports • ASTERIX CAT21 for ADS-B reports
Implementation considerations The primary advantage of WAM is that it can be installed in mountainous terrain, where the
line-of-sight propagation paths required for SSRs would be blocked. A second advantage is that, in many situations, its cost is lower than that of SSRs. Operational implementations include the U.S. Western Colorado and Juneau, Alaska, areas and the Innsbruck, Austria, region. It is reported that a WAM system has been installed in the Czech Republic. WAM systems are also used to verify aircraft altimeter accuracy in the U.S. and Europe.
Siting and installation The design of a WAM system is dependent upon proper site selections. Below are some issues to consider when selecting sites: • Accessibility (limited by terrain, weather, availability of power and communications, etc.) • Availability of power/backup power, communications • Site ownership: customer or local/state government owned sites may be preferred to commercial sites • Environmental impact • Available space • Interference with other site equipment • Site acquisition and preparation: leasing, permits, required construction, etc. • Installation season (extreme weather, high snows, high seas) • Accessibility during installation • Special training (survival training for oil platforms, tower climbing)
Communications Availability of communications is an important factor in site selection. Bandwidth, latency and reliability all need to be considered. In many cases, a dedicated network is not available. The system needs to rely on third party commercial communications such as local microwave networks, telecommunications provider, or satellite communications. == References ==