inReach, like SPOT, does not use the 406 MHz signal nor the system of satellites. Instead, it depends on the Iridium satellite constellation. Unlike SPOT, inReach is a two way system capable of receiving confirmation that the message was received. Like SPOT, the message is transmitted to the private Garmin Response//Garmin IERCC(FORMALLY GEOS International Emergency Response Center) who then notifies the appropriate SAR authorities.
inReach also provides tracking capability and two way SMS text messages.
The Somewear Global Hotspot, like inReach, also depends on the Iridium satellite system. It enables two-way messaging, live tracking, and 24-hour weather forecasting. In the event that an SOS distress signal is triggered, the information is transmitted to the GEOS who coordinates the rescue with the appropriate local authorities.
Main article: SPOT Satellite Messenger
SPOT does not use the 406 MHz signal nor the system of satellites. Instead, it depends on the GlobalStar satellite system. It has richer features (for instance, can send many non-emergency signals) – but it does not work in as many places as 406 MHz PLBs – for instance under dense forest canopy or steep canyons.6 When a user presses the "911" button on a SPOT device an emergency message containing the unit's identification and GPS location is transmitted to the GEOS International Emergency Response Center who then notifies the appropriate emergency agency for the region after first calling the user to ensure the transmission is not accidental.7
SPOT additionally has the ability to provide non-emergency web based tracking information. This allows family or friends at home to track the holder's progress. The tracking operates by sending a tracking signal to the GlobalStar network every 10 minutes. This feature can additionally be useful to provide location of an individual even if the individual is unable to activate the emergency '911' button.8
Yellowbrick, like SPOT, does not use the 406 MHz signal nor the system of satellites. Instead, it depends on the Iridium satellite system. Unlike SPOT, Yellowbrick is a two way system capable of receiving confirmation that the message was received and exchange two-way messages via short emails and SMS. Alert messages are transmitted to destinations specified by the owner.9
https://www.iercc.com/en-US/
https://www.garmin.com/en-US/blog/outdoor/get-to-know-garmin-response/
https://www.iercc.com/en-US/supported-devices/
[1] Yellowbrick two-way messenger datasheet http://www.yellowbrick-tracking.com/wp-content/uploads/2011/08/YB3_datasheet_en.pdf ↩
GEOS Search and Rescue https://www.geosresponse.com/ ↩
[2] NSARC minutes from December 2009 http://www.uscg.mil/hq/cg5/cg534/nsarc/NSARC_SEND_minutes_Dec09.pdf ↩
[3] Emerging technologies in commercially available alerting devices from ICAO/IMO JOINT WORKING GROUP, October 2009 http://www.icao.int/icaoimojwg/meetings/jwg16/docs/JWGSAR16_wp09.pdf ↩
[4] NATIONAL GMDSS IMPLEMENTATION TASK FORCE http://www.navcen.uscg.gov/pdf/gmdss/taskForce/TFSR_67.pdf ↩
SPOT Satellite Messenger FIRST LOOK – EQUIPPED TO SURVIVE (tm) http://www.equipped.org/SPOT_ORSummer2007.htm ↩
SPOT Emergency Response https://www.findmespot.com/en/index.php?cid=104 ↩
How SPOT works https://www.findmespot.com/en/index.php?cid=104 ↩
Yellowbrick Website Archived 2014-07-22 at the Wayback Machine http://www.yellowbrick-tracking.com/ ↩