Today
Today there are three types of distress beacons... marine EPIRBs, aviation ELTs, and individual PLBs. These beacons are credited with saving the lives of thousands of people in distress, and their capabilities continue to increase while their price continues to fall. But for all the successes, lives are still lost every year by people who are in urgent need of rescue but who aren't equipped with locator beacon technology.
A locator beacon is a radio-frequency transmitter that provides two critical pieces of information to rescuers: that someone is in need of help, and where that person is. Older locator beacons simply transmitted a signal that could be homed in on using direction-finding gear, but newer beacons also transmit a digital serial number to uniquely identify the beacon (which helps track down false alarms and quickly verify actual distress calls) and, when available, GPS-derived coordinates that narrow the initial search area from a radius of hundreds of miles to a radius of hundreds of yards, saving valuable time for the rescuers and also reducing the cost of search-and-rescue operations.
Our Goal
The goal of our project is to maximize the chances that a person in need of rescue can be found. To do that we need to put locator beacon technology right in the hand of everyone who might need it.
With the exception of a few extreme adverturers, nobody starts their day thinking that they'll need to be rescued before the day is out, and so an additional device that must be purchased and carried isn't a good solution for the people who get trapped in an unexpected blizzard, get stuck on a mountain road in the middle of the night, or who become trapped by rising floodwaters.
But almost everyone does carry a radio-frequency transmitter with them, in the form of a cellular telephone. And, when the networks haven't been disrupted by the same disaster, and the user hasn't driven or hiked out of range of the cellular network, dialing 911 is still the best way to get help. Cellphones have even been upgraded recently to add location information that can be used by the 911 operator to more precisely pinpoint the caller, in case they're not able to provide the location themselves.
How?
How do we make sure everyone is carrying a personal locator beacon? By enabling their cellphone to perform that function when it is unable to place a normal 911 call. And most important, we do that in a way that adds no hardware and no cost to the phone itself, so there should be no objection to regulation that requires that the feature be present in every new phone that is sold.
Implementation
When a cellular phone user dials 911, if the phone is in range a normal 911 call should be placed as it is now. But if the phone is out of range, the phone must enter "locator beacon mode". In "locator beacon mode" the phone transmits on a dedicated FCC-allocated distress frequency in the lowest band it is equipped for (800 MHz for an 800/1900 dual-band phone, 1900 MHz otherwise) and at the highest transmit power a digital distress message containing the serial number of the phone, and if available, a GPS-derived location. After the digital distress message, a carrier sufficient for local direction-finding is transmitted for several seconds, after which the phone enters a very low power sleep mode for ten minutes in order to conserve battery life as long as possible. When the sleep period is over, the cycle repeats with distress message transmission.
The distress message format should be modelled on the existing format for the 406 MHz Cospas-Sarsat system, but with a simplified modulation scheme that may be more easily implemented by any of the variety of digital cellular modulation modes in use without hardware changes... an example might be wide-FSK implemented by frequency synthesizer switching. The data rate should be sufficiently low as to enable significant processing gain at the receiver in order to increase the probability of detecting and accurately decoding a distress message transmitted by the very low powered phone which might be under dense foliage or snow cover.
It is not expected that this system would be detected by LEO or GEO satellites... instead receivers could be placed at existing rural cell sites (processing gain and the receive-only nature of detection means that a site that couldn't support a call from the phone might still be able to receive a distress signal), forest service lookouts, remote repeater sites, and on-board search-and-rescue aircraft. The ability to fly a high-altitude search for a radio-frequency locator beacon vs. a low-altitude search looking for a person or vehicle at visual or IR wavelengths significantly reduces the time until rescue and the number of resources required for a search for a known missing person, while the deployment of receivers at remote sites increases the chance to detecting a distress message transmitted before a report of a missing or overdue person is received.
What next?
This project requires several kinds of support in order to proceed and be successful. First, technical contributions are needed in order to determine the optimum modulation format given the wide variety of cellphone RF chain designs. Once this is determined, support will be needed in order to ensure that regulation is passed both to set aside the dedicated distress frequencies that are needed in/near each cellular phone band and to mandate that this capability be phased in to all new phones which are manufactured and sold.
What can I do?
If you are a cellular phone RF design expert, you can help by contributing to the technical specifications. If you are a legislator, you can make sure that the FCC gets involved and any supporting legislation is passed to make sure that this becomes a reality. And everyone can pass the word along and try to develop as much support as possible for the development and deployment of this lifesaving technology, hopefully before it is needed next.
Who are you?
I'm Matthew Kaufman. I'm a serial entrepreneur, but I'm not doing this one for the money, but because I've watched too many situations where it would have helped. When I was younger, one of my ham radio hobbies was to track down transmitters using my direction-finding skills, so I've been interested in this sort of technology for a long time. I got the initial idea while watching the aftermath of hurricane Katrina, with folks stuck up in attics and along relatively unpopulated coastline starving to death while rescuers tried to find them... I shelved it in the back of my mind until I was following the search for James Kim and his family. The unfortunate tragedy of James' death reminded me that something really ought to be done about turning everyday technology into life-saving technology. If any legislation is written in order to further this project, I would suggest that it please be introduced in memory of James Kim.
Contact Information
For now please send email comments or suggestions to matthew@eeph.com. As this project gains more momentum we'll be adding a wiki and/or comment pages on the site and additional technical documentation. But for now, lets get started before someone else needs to be found!