The performance of the heading sensor is essential for the autopilot. The best steering algorithms cannot compensate for an unstable and inaccurate heading reference
GPS tracking devices have finally reached the mass markets, enabling everyone from parents to law enforcement agencies to track the movements of vehicles, people or animals. Prices are down considerably (<$300) and monthly service plans have becomes more reasonable, starting at $20-$25/month. Three of my favorite models are made by Covert Track at GPS Intel www.gpsintel.com. These models include the CT-100, CT-200 and Trim Trac Pro.
The CT-100 is small and runs off a 9-day internal battery that would have to be recharged at some point. When a request is made to locate, it attempts to find satellites. But if this is unsuccessful, the device will triangulate off Sprint cell towers and still send the location to the reporting website (part of your subscription fees). This enables the device to be tracked inside a vehicle, in a garage or a building.
The CT-200 does not offer cell tower triangulation but has an enhanced satellite tracking system that has a much better uptime than traditional gps devices. As part of the Worldwide Reference Network, the satellite data is collected 7 days in advance so that the satellite data is readily available to locate the receiver on demand. This enables the tracker CT-200 to be found even indoors. The internal battery should last up to 10 days.
The Trim Trac Pro is the only model that allows you to attach an external gps antenna for even better tracking. This enables you to hide the tracking device in a more hidden location while running the antenna to a better view of the sky. It operates on 4 AA batteries which can be monitored remotely but will remain dormant when the vehicle is not in motion. Location can be polled on a website or via cell phone. You can view street and aerial overlay of location via the website, get address and monitor speed. Trim Trac Pro is a little larger than the other 2 units.
