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GPS Technology in Medical Alert Systems


GPS (Global Positioning System) is a satellite-based location identification technology commonly found in electronic products. Car navigation systems and driving apps for smartphones all use GPS to help you reach your destination. GPS is also found in medical alert systems. 

Alert1 offers two mobile medical alert systems that use GPS: Kelsi Pro mobile medical alert and PAX Plus mobile + home fall mobile medical alert. Thanks to these two alarm systems, our members are protected anywhere they go. 

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The History of GPS Technology

futuristic clock.alert1 medical alert systems

Like Cheetos or deli meats, GPS technology was funded by U.S. Department of Defense. The original purpose was to accurately coordinate and target locations for military purposes. During the Reagan administration, the government opened up the technology for broader public use. By the Clinton administration, civilian use far outpaced military use. Today GPS technology powers much of what we do, including the PAX Plus and Kelsi Pro mobile medical alert systems. 

How GPS Medical Alert Systems Work

PAX Street

GPS is a constellation system of 29 earth orbiting satellites. It takes 24 satellites to provide coverage around the world. The other five satellites serve as backups. The satellite flight paths are arranged so that at any time anywhere on earth, there are always four satellites visible.

The GPS chip in your PAX Plus or Kelsi Pro medical alert receives radio signals from the four visible satellites. The chip then determines your location in a process called trilateration. Kelsi Pro and PAX Plus use the signals from at least three of those satellites to determine your precise location. Alert1 then knows where to send you the help you need, fast.  

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Mobile Technology as Backup

Kelsi Pro in Hand

PAX Plus and Kelsi Pro also use U-TDOA (Uplink Time Difference of Arrival) location technology. U-TDOA is a position-location technology used by mobile phone networks. 

Another Alert1 mobile medical alarm system that uses U-TDOA is the Kelsi. Kelsi is our classic mobile medical alert help system. If you're looking for a mobile system that travels with you without fall detection, Kelsi is the way to go.

Kelsi, Kelsi Pro, and PAX Plus all use U-TDOA to help keep you safe. But what exactly is U-TDOA? 

U-TDOA works through microprocessors in our mobile alerts that connect with receivers in cellular towers. They pick up the signal from your mobile medical alert device and determine your location in a process called multilateration. Our mobile alarm help buttons calculate the time it takes a signal to travel from your device to the Location Measurement Units (LMUs) on the tower. By using the timing information from multiple LMUs, we are able to know your precise location.


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The Benefits of PAX Plus and Kelsi Pro

  • Location Accuracy: PAX Plus and Kelsi Pro are some of the most accurate mobile medical alert systems on the market. At Alert1, we're able to use both GPS and cellular location technology to determine members' locations to within a few meters. This gives you peace of mind knowing we will quickly send help, regardless of where you are.
  • New Technology. Medical alert technology is rapidly developing with PAX Plus and Kelsi Pro leading the charge. Trust Alert1 to stay on top of these new technical developments, bringing you the best in medical alarm system help buttons.
  • Trusted Processes: PAX Plus and Kelsi Pro leverage Alert1's trusted and proven response process. When you press your help button, our 24/7 Emergency Monitoring Center will come on over the 2-way speaker and ask if you need help. From there, we will contact your Circle of Care or 911.
  • Industry Leading Fall Detection: Alert1's Kelsi Pro and PAX Plus offer more protection than ever before. The mobile fall detection pendant automatically senses a fall and notifies our Command Center 24/7. This lets you continue to travel and have fun, without worrying the fear of a fall. 
  • Great Reviews: Alert1 members are loving their new mobile help buttons with GPS. With all the great benefits of our home system, but designed for on the go, you will get help anywhere you are.

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