Isaac Botkin dives into the importance of having a dedicated GPS device, how they work, and how to use them, and touches on GPS spoofing and jamming. Why? Because our system is more fragile than we think and GPS is one of the most secure and reliable navigation tools at our disposal.
The video provides a (very) brief introduction to GPS technology and compares the features of several Garmin devices. The video explains some practical applications of GPS and why it’s important for everyone to own a dedicated GPS system in our happening world.
GPS is a highly useful item with specific potential weaknesses.
I believe it was originally conceived as a military tool, to aid navigation, especially airborne nav. Prior to that we had a system of satellite nav (INS) that was both complex and difficult to calibrate and manage. It seemed most useful to long-haul aircraft. But there was a need for both long haul nav and a short range nav, especially with the advent of fast, single-seat fighters. GPS comes along.
Since GPS can be highly accurate the military has a built-in ability to degrade its accuracy in times of need (war, for example). This was created so enemy missiles could not use our GPS to target our missile silos in particular, but us in general.
The other weakness is that it can be jammed or spoofed. There is a famous incident way back in the 90’s where a lab accidentally left a piece of equipment on for the weekend (while they were off) which ended up trashing the GPS nav ability of general aviation aircraft in the upper Hudson River Valley, centered on Schenectady. Monday morning the mistake was located and the equipment turned off, but for the weekend all the small craft in the area could not use GPS to navigate.
In my more limited experience, which ended about 2004, GPS was a great way to fly direct to where ever you wished to go. However, some of the busier Centers would not accept GPS direct and as soon as you were handed over to them, they would reroute you VOR to VOR, which in reality meant along published air lanes - where, of course, aircraft were the densest. This would often mean merely a displacement of a matter of miles but an overall increase of flight time (so gas) to get where you wished to go. New York Center was particularly prone to this.I can’t remember a flight into NY Center without the reroute. It would cost us 4-5 gal of gas - for no real reason.
When speaking of GPS, it’s important to keep in mind precisely what it is and isn’t, as there is a great deal of confusion about the matter among the public. GPS (and other global navigation satellite systems [GNSS] such as the Russian GLONASS, European Union Galileo, and Chinese BeiDou) provide signals from satellites as well as broadcast ephemeris information which allow a passive receiver to compute its latitude, longitude, and (less precisely) altitude on the Earth, along with a high precision time signal. The receiver can then use this information to estimate velocity along these axes. That is all GPS does.
All other functions attributed to “GPS” are, in fact, separate applications which use as input the position information obtained from the satellite system and receiver. Such functions as display of location on a map, driving directions, nautical and aeronautical navigation, precision approaches to airports, tracking of vehicles, warning of terrain conflicts in aviation, etc. are not functions of GPS, but rather independent services, some built upon “big data” either stored locally or accessed over a network, which use the position from GPS to determine the user’s position (and sometimes velocity), then provide information based upon their own databases and calculations.
So when you hear somebody blame GPS for sending them the wrong way down a one way street or on a circuitous route when a better one was available, this isn’t the fault of GPS but rather the application which uses data from GPS, but is entirely responsible for everything beyond instantaneous position and time.
