By Tim Dees
When radio, landline and cellular communications are unreliable, satellite conduits may be your only option.
Every user’s situation is a little different, so it’s difficult to talk about a “standard” public safety satellite communications (satcom) solution. You may need voice communication only, or voice+data. You may also be in a situation where sometimes you will have access to a standard cellular network, and sometimes reliant on the satellite link only. Most agencies contract with a provider that can supply some combination of equipment and airtime to meet your needs.
Handsets
Handsets for satcom communication are bigger than the cell phones most of us have today. The newest models have the “candy bar” form factor of about ten years ago. The antennas range from small and flexible to the size of a small fishing rod, and they operate like a cellular phone.
An internal battery will run for 15-30 hours on standby and provides 2-4 hours of talk time. Data-compatible phones will work as modems, but don’t expect to be watching YouTube videos. Data speeds vary between 2400 and 9600 bps (a typical broadband connection is about 1,000X as fast). That’s enough for simple text, but not much else.
Handsets typically cost between $500-$1,500, plus accessories, but that’s not where you’ll spend the most money. Air time on a satellite network costs $1 or more per minute. Air time is sold in packages of 100-5,000 minutes, and the more you buy, the greater the discount. You may be able to negotiate a pay-as-you-go rate, but it will come with a monthly service and access charge, whether you use the phone or not.
Determining need
If your need is limited to tracking of vehicles or other assets, you can buy simpler transceivers that send data bursts containing geographic coordinates at preset intervals. On the other end of the use spectrum, dish antennas mounted on vehicles are capable of high-speed communications, serving as the base station for multiple users within conventional radio range of the base. These setups are best for remote search and rescue or disaster mitigation operations, where units have to be self-provisioning and self-maintained. These are custom solutions that will probably involve several vendors and a systems integrator.
Networks
There are several satellite networks, and communications gear generally works on only the network it’s designed for. The most prolific networks are:
• Globalstar: good coverage through North and South America, Australia and Europe
• Iridium: 66 low-earth-orbiting satellites providing a fully meshed network and coverage over most of the globe. Iridium is the largest communications satellite network.
• Inmarsat: designed primarily for marine communications. Good coverage except for extreme latitudes at each pole.
• Thuraya: coverage in the Eastern hemisphere, including Africa, Australia, Europe and Asia. No coverage in North and South America.
Tim Dees is a retired police officer and the former editor of two major law enforcement websites who writes and consults on technology applications in criminal justice. He can be reached at tim@timdees.com.
