These two military-focused architectural standards provide approaches to system-level development and sensor-centric designs. The military services have long had a dilemma with respect to technical standards and the long-term viability and compatibility of associated systems. On one side, they would like to be able to leverage the latest, newest technologies for the performance and cost […]
What? LORAN may be back? Why? How? Part 3
The defunct, obsolete LORAN navigation system is being revived with enhancements to overcome GNSS’s potential performance and availability risks. Congress debated whether to retain and upgrade the LORAN-C infrastructure to become enhanced LORAN (eLORAN), a national backup to GPS. In October 2009, Congress enacted a Department of Homeland Security appropriations measure allowing LORAN-C termination. […]
What? LORAN may be back? Why? How? Part 2
The defunct, obsolete LORAN navigation system is being revived with enhancements to overcome the potential performance and availability risks of GNSS. Before GNSS and GPS, and before INS systems were available, another type of RF-based position-determining system was in wide use: LORAN. Q: What is LORAN? A: LORAN is short for LOng RAnge Navigation. LORAN, […]
What? LORAN may be back? Why? How? Part 1
The defunct, obsolete LORAN navigation system is being revived with enhancements to overcome the potential performance and availability risks of GNSS. There’s no need to tell the readers of this FAQ about the impact of global navigation satellite systems (GNSS) on positioning, navigation, and timing (PNT) services from global, regional, or even localized perspectives. Billions […]
The Doppler effect: From highly ridiculed to absolutely indispensable, Part 2
Originally derided as scientifically erroneous, the Doppler effect is now a vital tool in all aspects of technology, ranging from microscopic to galactic. Doppler, back in the day – and now The explanation of the Doppler effect is almost intuitive to us, with our understanding of wave phenomena along with available frequency sources and measurement […]
The Doppler effect: From highly ridiculed to absolutely indispensable, Part 1
Originally derided as scientifically erroneous, the Doppler effect is now a vital tool in all aspects of technology, ranging from microscopic to galactic. Engineers are familiar with many “effects” ranging from widely used ones such as the piezoelectric effect to somewhat lesser-known ones such as the RF skin effect and even less-familiar ones such as […]
Satellite-based search-and-rescue, Part 4: Enhancements, even the moon
A sophisticated satellite-based system allows pinpointing a person’s location in a dangerous, isolated situation on land or sea. It thus hopefully speeds their subsequent rescue in many cases. This final part looks at the next generation of system satellites and some ideas for a similar lunar system. The MEOSAR satellites The most recent enhancement to […]
Satellite-based search-and-rescue, Part 3: Space segment and satellites
A sophisticated satellite-based system allows pinpointing a person’s location in a dangerous, isolated situation on land or sea. It thus hopefully speeds their subsequent rescue in many cases. Cospas-Sarsat uses three types of satellites: low-Earth orbit search-and-rescue (LEOSAR), medium-Earth orbit search-and-rescue (MEOSAR), and high-altitude geosynchronous orbit search-and-rescue (GEOSAR satellites). There are five LEOSAR, seven GEOSAR, […]
Satellite-based search-and-rescue, Part 2: Ground segment and transmitter beacons
A sophisticated satellite-based system allows pinpointing a person’s location in a dangerous, isolated situation on land or sea. It thus hopefully speeds their subsequent rescue in many cases. Over one million emergency beacons are in use worldwide, all operating at 406 MHz (with some exceptions, called out below). Cospas-Sarsat does not manufacture or sell beacons. […]
Satellite-based search-and-rescue, Part 1: The overall system
A sophisticated satellite-based system allows pinpointing a person’s location in a dangerous, isolated situation on land or sea. It thus hopefully speeds their subsequent rescue in many cases. You’ve undoubtedly seen or read stories about someone miraculously recused at sea or in some relatively uninhabited, remote part of the Earth, without a way to call […]
