Delorme inreach question

[Matt_OCENS]

If the Iridium devices are not constantly connected, how does a sat phone know when to ring? Don't feel compelled to answer if you don't' want to. I can do research if I really want to know, but it is interesting to me. What's being described is very different product behavior from say a Garmin using NAVSTAR. For example, I have a Garmin GPS 60CSx which I've owned since 2006. When turned on, and it has a GPS fix, it never stops tracking the satellites that are in view. But the NAVSTAR satellites orbit the earth twice a day, so their moving too.

You are correct in that with an Iridium (or other satellite) handheld phone, it has to be registered with the satellite in order to receive a phone call. In relation to my comment about power, the Iridium 9575 has about 30 hours of standby time, whereas the InReach SE has about 100 hours of battery life when sending position reports every 10 minutes, so by strictly managing short data bursts, you are able to get more usage out of a battery cycle since the device will go into standby mode in between intervals.

To elaborate further on your question, the Iridium 9575 will also send automated position reports and essentially works in the same way as the InReach. It uses Short Burst Data (SBD) to send the position report in a quick packet burst (thus the name). Either device would have to be registered to the network in order to do this, however all it needs is a quick window to get the report out and the reports can be queued until a connection is available as was already mentioned. Similarly, SMS messages don't require a long window of connectivity and inbound messages will sit at on the network until your device connects. A voice call obviously needs a continuous connection since it is in real time.

 

[Crom]

Makes perfect sense. Thanks Matt.

 

[fishbum]

Don't confuse GPS with Iridium... A Garmin "GPS Receiver" does just that - receives GPS signals... it can see up to 12 GPS satellites above the horizon at any given time in order to 'Trilaterate' your position. It only receives GPS, GPS is a broadcast signal from the satellites to the earth (not from earth up to GPS satellites).

Iridium has two channels - Voice, and data. You actually use the Short Burst Data (SBD) channel to make the voice channel available, then talk on the voice channel (as long as it can stay connected)....