|Better Standards Will Make Better Emergency Beacons|
Status Report by Doug Ritter
Some of the most critical Conclusions in the Equipped To Survive Foundation's ground-breaking first report on 406 MHz Location Protocol (GPS enabled) Emergency (Distress) Beacons (www.equipped.org/406_beacon_test_toc.htm) revolved around the obvious ineffectiveness of International and U.S. standards for these beacons to ensure that they would provide the real-world performance consumers should reasonably expect. Therefore a call for better standards more closely related to real world use was a principle feature of the Recommendations made in the report.
Since the release of that initial report, I have been an active participant on an RTCM (Radio Technical Commission for Maritime Services) subcommittee and at COSPAS-SARSAT Task Group and Joint Committee meetings tasked with revising the standards covering these emergency beacons (see below for more details). I am the only consumer advocate attending these meetings. At the COSPAS-SARSAT Open Council Session held November 7-10 in Montreal, Canada, revised standards were approved that significantly raise the bar for these beacons and implement many of the Recommendations made by Equipped To Survive Foundation.
I have been pleased by the unexpected quick response of the international community to our findings. These revised standards represent a noteworthy philosophical shift on the part of COSPAS-SARSAT and go a long ways towards ensuring that these beacons will work as expected when lives are at stake.
While the optimum metal ground planes previously used to test the beacons remain, a new test with the beacon isolated from the ground plane has been added. This is considered a worst case scenario and ensures that a beacon is not optimized only for performance with a special ground plane. COSPAS-SARSAT has recognized that these beacons are not just used in their design environments (EPIRB floating in the water, for example), but that they are often used in other environments (EPIRB on the deck of a vessel or inside a life raft or cabin, for example). With the exception of permanently mounted beacons in aircraft, all beacons, EPIRB, PLB and ELT, will now have to be tested with this alternate isolated ground plane.
COSPAS-SARSAT also added fundamental testing for GPS functionality. Previously, the only requirement was that it not interfere with the 406 MHz distress alerting. Now the GPS receiver will be tested with the beacon transmitting on 121.5 MHz (or an approved alternate test frequency when a 121.5 MHz homing beacon is included, always the case with all U.S. approved beacons). The homer transmission can cause interference with the GPS receiver. It must also be tested in real world environments with a 10 minute maximum location acquisition and transmission time and much tighter accuracy. While this new standard doesn't add any tests for performance with a less than optimum view of the GPS satellites, it is a huge step forward towards assurance that an optional GPS receiver included in a beacon functions at least at a minimum level of performance.
All of these beacons use the 406 MHz distress alerting frequency in conjunction with the COSPAS-SARSAT system of Low Earth Orbit (LEO) satellites and Doppler principles to provide primary position information. The purpose of GPS-enhanced 406 MHz beacons is to save precious rescue time by supplying much more precise location information via their own GPS-derived location through Geostationary (GEO) satellites - ever present in the sky - rather than waiting for an orbiting satellite to appear in view and then obtain the less accurate Doppler computed location.
COSPAS-SARSAT declined to add the option for an optional self-test of an included GPS reicever with transmission of the location to allow a user to check the accuracy of the GPS, provided they have the appropriate receiver. The accuracy requirement for GPS are also considerable less stringent than what RTCM and the Task Group had called for. So, there's still work to do at this level as well.A brief review of all the changes, prepared by the COSPAS-SARSAT Secretariat, can be read in this summary report (opens a new browser window). The new standards, T.001 and T.007 may be downloaded at: http://www.cospas-sarsat.org/Documents/tDocs.htm.
Funding permitting, I will continue to participate on these committees, representing the end user, with the goal of further improving the standards for these beacons. Not all the recommendations we've made have yet been implemented. The RTCM SC-110 subcommittee continues to work on much stricter performance standards for GPS, using GPS simulators for testing, and on other areas related to the real-world use of the beacons that are in need of improvement. While we are making good progress, there are still a good number of meetings required to complete this critical RTCM work and carry it thorugh the COSPAS-SARSAT standards revision process.
Attending these meetings takes money and the Foundation has very limited resources. Your contributions are needed to support my continued advocacy at COSPAS-SARSAT and RTCM meetings. Contributions from readers like you have enabled me to help push through important changes, we're making progress, but much more still needs to be done. You can help with your TAX-DEDUCTIBLE DONATION.
The cost of travel is a major expense. If you have loads of frequent flyer miles, why not help by donating a Frequent Flyer Award to help me travel to these meetings. Click here for more information.
|ETS Foundation 406 MHz Beacon Test.|
Recording number of satellites in view,
signal strength and location prior
to beacon activation.
I believe it can be fairly stated that this is in good part due to the pressure that the media spotlight has put on the industry as a result of the Foundation's revelations. As more than one industry representative has stated, "the world has changed," and they must step up to the plate and develop better and more responsible standards.
Herein is a Status Report as of March 22, 2005. Improved standards development for 406 MHz Emergency Beacons has been moving forward on dual tracks. The first effort was initiated within the RTCM (Radio Technical Commission for Maritime Services) SC-110 subcommittee in conjunction with the RTCM Annual Conference and NOAA's Beacon Manufacturers Workshop held in St. Petersburg, Florida, last May. This was introduced by the subcommittee chairman, Paul Steward, formerly the COSPAS-SARSAT Liaison Officer at the U.S. Coast Guard before he retired last year and joined industry. Equipped To Survive Foundation has joined RTCM. I have attended these meetings and have been an active participant in the process during the three additional meetings conducted to date at RTCM offices outside Washington, D.C. While this is a U.S.-based organization, its work also directly or indirectly affects international regulations and standards and the committee has international participation.
A number of major areas are being addressed in the RTCM effort. NASA and NOAA have both been supporting this effort with technical experiments and work related to the RTCM committee's attempt to develop antenna signal related test standards for the beacons more closely aligned with real world use of these beacons. This is an effort to move away from the highly unrealistic tests currently used to ensure they will get a signal through to the satellites in real world use (more on this later). In the case of PLBs, some environmental test standards also need to be revised to reflect real world use of these beacons. In addition, some labeling and instruction deficiencies may be addressed.
With regards GPS integrated into these beacons, we are working to develop standards that require a minimum performance level in a degraded environment test, to reflect the real world use of beacons where they do not have an optimal view of the GPS satellites and where they must work while the beacon is transmitting its alert and homing signals. It's been long established that this can have a significant effect on GPS performance; especially the 13th harmonic of 121.5 MHz. Testing GPS without these active transmissions is highly misleading.
To date, much progress has been made with agreement on adverse real world scenarios and narrowing these down to the most adverse case for land and marine use. Now we are focused on translating these scenarios to a test configuration that can be duplicated in all COSPAS-SARSAT approved laboratories and in establishing pass-fail criteria. Much of the work that NASA and NOAA are doing relates to these issues.
|Overhead forest canopy at obscured GPS test location|
during ETS Foundation 406 MHz Beacon Test.
None of the PLBs acquired a GPS location in this test.
|Sample of a typical GPS Timing Scheme.|
Each manufacturer's scheme is different.
The second track developed after RTCM began its work and involves the international COSPAS-SARSAT (CS) organization that operates and regulates the satellite and beacon system. A Task Group Meeting agenda was issued by the Secretariat that included a number of issues relating to the ETS Foundation report's findings, with this connection specifically made when it was issued. I attended this meeting the week of February 14 in London, England. There was considerable concern that COSPAS-SARSAT and RTCM compliment each others work and that nothing happen at COSPAS-SARSAT that would hurt the RTCM efforts.
|Doug Ritter attending COSPAS-SARSAT Task Group Meeting - London|
This was my first such meeting, but according to those present, attendance at this meeting was about double what is typical, attesting to the interest that the agenda stimulated. I won't bore you with the mind-numbing details of 4.5 days of meetings, but let me touch on the highlights that relate to our concerns, much of which parallels the work being done by RTCM.
First, CS has finally recognized that in the real world beacons are often used in
environments other than that for which they have been tested--and likely optimized. This change goes a long way toward putting in place one of the primary and fundamental Recommendations that was made by the ETS Foundation in last year's beacon test report.
|Preparing to test an EPIRB inside the life raft.|
during ETS Foundation 406 MHz Beacon Test.
Another example that helped bring this all to the fore is PLBs, theoretically for use only on land, which are currently tested resting only on a nearly perfect ground plane that has little relationship to the real world. In actuality, PLBs are marketed for use, and have been used, on both land and water. The end result of our discussions was a matrix that defines what ground plane conditions must be used in antenna testing, depending upon the likely actual beacon operating environments. As conceived, this at least doubles the critical antenna performance tests most beacons have to pass, and in at least one case, triples them.
Towards this end, considerable discussion and a number of papers were presented (including some from our RTCM work and NASA) that suggested that a beacon in free space with no ground plane represents the most difficult circumstance and most closely represents the poor ground planes found when a beacon is set down on dry sand or solid rock or on the deck of a composite built vessel, as well as if held in the hand by a survivor. This was tentatively selected as the alternate ground plane for most beacons with both the French and U.S. (NASA) leaving with an action item to perform a series of tests to further validate this assumption, hopefully, and to determine exactly how to specify this test set-up in a manner that is repeatable in all the COSPAS-SARSAT approved labs around the world for certification purposes. This all ties very closely in with the RTCM's efforts.
Part and parcel with this move was the determination that the recently coined nomenclature, "Multi-Environmental Beacon" (MEB), would NOT replace the term Personal Locator Beacon (PLB). Since it was now accepted that virtually all beacons are actually multi-environmental beacons in the real world, the nomenclature PLB will be retained and MEB is no longer to be used in its stead.
The second major move was made in relation to included GPS (actually referred to as GNSS by COSPAS-SARSAT - Global Navigation Satellite Systems – a PC technical term which, while it includes GPS, GLOSNAS (Russian) and the upcoming Galileo (EU) navigation systems, mostly mean GPS right now). Until now, CS' attitude towards GPS included in a beacon was simply to ensure it didn't interfere with the 406 MHz alert signal and that if it sent location data to be included, that it was coded correctly. They had no interest in whether or not it worked and in fact shied away from any sort of testing that might imply that their approval certified that it did work. This was a distinction lost on 99.9999% of consumers. As our tests showed, this could be a problem.
Besides improvements in testing to ensure correct coding (more on that later), CS is moving towards making sure that any integral GPS actually works as installed in the beacon. While RTCM is working towards standards that will test for degraded environment performance as can often occur in the real world, CS was not quite ready to go that far. However they have added the requirement that testing of GPS performance be done:
a. with the 406 MHz and 121.5 MHz homing transmitters transmitting. This did raise some issues, however. When done within a shielded GPS simulator this isn't a problem, but when testing beacons in the open as is mostly done today for COSPAS-SARSAT approval, 121.5 MHz transmissions can cause all sorts of headaches and requires coordination with the country's MCC. In addition, some countries really don't like the concept of live 121.5 MHz transmissions, so it becomes very problematic. One participant advised that their studies have shown that use of 121.65 MHz, the international test frequency, has the same effect. Another beacon manufacturer advised that they have long used 121.6 MHz. Others noted using 121.7 MHz. Pending confirmation by the U.S. and others that this adequately simulates use of 121.5 MHz, the new standard requires testing of the GPS with live 406 MHz and 121.6 – 121.7 MHz transmissions.
|EPIRB in the ocean during|
ETS Foundation 406 MHz Beacon Test.
CS is leery of developing a tougher standard that requires the use of simulators due primarily to concerns about cost to the labs and have deferred any action on standards that would require the use of simulators. Further investigation into the cost issue is an action item for the Secretariat. I pointed out that it really wasn't necessary for the labs to purchase their own simulators; they just needed to be able to have access to an appropriately certified simulator, of which there are many. Meanwhile, RTCM is already aggressively moving in this direction, so the CS position may be co-opted by RTCM's work. CS will wait to see what RTCM does in this regard before taking any more stringent steps, but this is already a huge step forward that at least partially implements another Recommendation in the ETS Foundation beacon test report.
The only issue on which we lost out, partially, was that of testing with the new script that CS will be using to simulate various GPS operational conditions. This script will ensure the beacon correctly codes the location, updates the location when moved, etc., and that all beacons have to meet the same standard by using the same script. I wanted this script to be prepared by CS and for the testing to be done at the labs, but there was considerable opposition to this. In fact, CS originally wanted the entire GPS certification to be done simply by means of a statement by the manufacturer that it met the standards. In the end it was decided that the script testing can be done by the manufacturer who will certify that the beacon does what it's supposed to do based on various GPS inputs. The manufacturers will also develop their own software scripts based on the very detailed scenarios provided by CS. However, in the end the most important point was that a lab must carry out the actual GPS tests.
I was quite concerned about the agenda item having to do with Policy for Conducting Life Beacon Testing which was aimed at reducing the number of live beacon tests performed. In the end, the primary action item relating to this agenda item was that CS would post information on its Web site describing the adverse impact of live testing and discouraging “uncontrolled” live testing. Based on my expressed concerns and objections, the word “uncontrolled” was added into this action item to ensure that this did not provide for any possible interpretation that CS supported precluding or discouraging consumer testing using live beacon tests such as we have conducted.
As an offshoot of this discussion, a suggestion was made for anyone to present a paper to the Joint Committee that would recommend changes to the allowable coding for the self-test burst by providing for inclusion of the latitude and longitude in the beacon self-test burst. This is an excellent idea, long overdue, and this would partially implement another recommendation in the ETS Foundation beacon test report. This may be a paper that ETS Foundation will take on, if nobody else does so, though I expect other interested parties will.
|Doug Ritter (in yellow shirt) at|
2004 Beacon Manufacturers Workshop.
So, now what will happen? That depends in large part on how generous ETS Foundation's benefactors are. In order to see these COSPAS-SARSAT changes through to fruition, I need to attend the week-long Joint Committee meeting in London in June. Any objections raised, especially relating to the increased cost of approval, will need to be forcefully argued against, lest the changes be diluted or set aside.
In addition, between now and June there are two more RTCM meetings scheduled, one in D.C., the other in St. Petersburg, Florida, in conjunction with the annual Beacon Manufacturers Workshop sponsored by NOAA. CS is looking to RTCM to lead in this matter. While we are making good progress, there are still a good number of meetings required, even beyond these, to complete this critical RTCM work.
Attending these meetings takes money and the Foundation has very limited resources. Your contributions are needed to support my continued advocacy at COSPAS-SARSAT and RTCM meetings in 2005 in London, Washington D.C. and St. Petersburg. You can help with your TAX-DEDUCTIBLE DONATION.
The cost of travel is a major expense. If you have loads of frequent flyer miles, why not help by donating a Frequent Flyer Award to help Doug travel to these meetings. Click here for more information.
Executive Director: Doug Ritter
© 2005 Equipped To Survive Foundation, Inc. - All rights reserved.
Check our Copyright Information page for additional information.