The key's the key!Your Army-issued global positioning system Global Positioning System: see navigation satellite.
Global Positioning System (GPS)
Precise satellite-based navigation and location system originally developed for U.S. military use. (GPS) receiver, the PLGR PLGR Precision Lightweight GPS Receiver (US DoD)
PLGR Plunger or the DAGR DAGR Defense Advanced GPS Receiver
DAGR Direct Attack Guided Rocket , can receive--and should receive--a secure GPS signal.
In order for your GPS to receive the secure signal, the receiver must be crypto-keyed. This is the job of your unit's COMSEC (COMmunications SECurity) A term used primarily by the military to denote measures for ensuring secure communications, including integrity and confidentiality during transmissions. custodian. Your custodian will load the crypto variable (CV) key to your DAGR or PLGR to let it receive a secure signal.
Your receiver will tell you if it has the key and if it's the current one. Watch the screen when you turn on your receiver and if you don't have the current key, it will read "No CV Key for Today." If you don't have any key, it will read, "Warning No CV Keys Loaded." If either of these warnings show up, get to your COMSEC custodian before you use your GPS.
First, it's mandatory! Use of un-keyed GPS devices is only authorized for training and for research and development programs. DoD policy says combat and combat support operations must use crypto-keyed GPS receivers. If you want to read the official policy, go to the PM GPS website: https://gps.army.mil
Once there, go to "About GPS" and click on "PPS (Packets Per Second) The measurement of activity in a local area network (LAN). In LANs such as Ethernet, Token Ring and FDDI, as well as the Internet, data is broken up and transmitted in packets (frames), each with a source and destination address. Policy."
Second, secure GPS devices have a selective availability A function in the GPS navigation system that deliberately introduced random errors for civilian GPS receivers. It was implemented to prevent enemy troops on foreign soil from using the GPS system to their advantage, while allowing friendly troops to obtain the true signals in GPS anti-spoofing module (SAASM SAASM Selective Availability Anti-Spoofing Module
SAASM Selective Availability Anti-Spoofing Module (US DoD GPS system) ). Not only does SAASM limit spoofing, but it also provides greater position accuracy and situational awareness--two things that could save your life in combat.
Finally, most signal interference is not intentional. Crypto-keyed receivers can resist this unintentional jamming at 10 times the level of interference that un-keyed receivers can resist.
One last word: Put those commercial oft-the-shelf GPS devices back on the shelf. They may have a fancy doodad or two that the PLGR or DAGR doesn't have, but they are not secure! Also, they use the standard Positioning Service Signal, which is less accurate and more prone to interference than the military-only Precise Positioning Service (PPS) signal.