--You are confusing Nav Sat with GPS. Two Hundred dollar GPS navigation devices do not have the capabilities stated in the article.--
Sat. Nav. IS GPS. Please clarify what 'capabilities' are stated in the article that GPS does not have.
The article states that the devices the Mexican govt wants to issue would allow the illegal alien to summon help if he/she were in trouble and needed rescue. Normal GPS receivers only give the user their position, are receivers, and don't have a way to be tracked.
In general the article is poorly written by somebody that doesn't know about these devices, but for the capability to be found and rescued it would have to be a Personal Locator Beacon. PLBs broadcast on an international SAR frequency of 406 Mhz. Low end units don't have a GPS system and narrow down the search grid to about 25 sq miles. The better units either have an interface for a GPS receiver to upload coordinates or have their own GPS onboard to generate their own coordinates.
My concern would be, especially if they don't use GPS equipped units, that the U.S. will be expending an inordinate amount of time and resources chasing these PLB signals. If I was a coyote I would have one of my buddies fire up one of these things and leave it 25 miles off my route just to pull assets away from the active route. The coyotes will have an unlimited supply of the devices from their previous customers.