You're right, because look at what I found:
Covertrack CT-100 Advanced GPS Tracker
The CT-100 uses the most advanced location techniques available to determine the location of an asset. The CT-100 enables the operator to obtain a location fix inside buildings, parking garages, and other dense urban areas. There is no external antenna needed and the device does not need to “see the sky” as normal GPS devices do. The CT-100 will work inside the trunk of a vehicle, in armored vehicles, indoors, and other locations where a standard GPS device would fail. The CT-100 will also defeat many of the GPS jammers that are now on the market.
How Does it Work?
When the CT-100 is requested to report it’s position, it attempts to obtain a fix using GPS satellites. If it is unable to obtain a GPS fix due to the device being inside a building or under metal, it reverts to cell tower triangulation mode. It will then automatically determine its position by triangulation with Sprint cellular towers in the area using AFLT (Advanced Forward Link Triangulation) This whole process is normally done in under 10 seconds. The device is also always on, so it can be “polled” any time. Reports are then transmitted to a web site where the user can determine the location of the asset. Tracking Plans start at $19.95 per month.
That means you'd also need one of these:
Silencer - Full Spectrum Cellphone Jammer (CDMA + GSM + 3G)
