I was helping a MSA member set up SeaClear on his boat and some old thoughts about the use of navigation electronics resurfaced on my mind. We had to work with the boat GPS unit and SeaClear. The ever present Global Position System (GPS) units are available from the golf course to the sea; GPS units are everywhere to tells us where we are (in case we really want to know within a 33 feet radius of certainty.) Here are some thoughts:
#1 Do I really need the latest and greatest of GPS units?
Over years of DIY projects, I leaned to think of any system in terms of components. For GPS to function, it must have two main components: satellites, and a receiver. What we buy at the store is obviously the receiver (although, you might buy a bargain satellite in the former Soviet Union.) The receivers we are accustomed to see, and to buy, are in turn another system based on components.
The essential part of the receiver is the GPS chip. This is the component that receives the signals from the satellites and it does the magic of telling us where we are. The other common components of the GPS receiver unit are:
| a) A display for the information coming from the GPS chip. |
| b) A keypad to enter commands for the unit. |
| c) Storage for saving configuration, waypoints and routes. |
| d) Power for all the above (internal and external for portable units.) |
| e) A connection port for data interchange. |
A GPS unit that has a recent manufactured chip with the above components is good for me.
#2 I don't need my GPS unit to always tell me where I am, just occasionally.
What I need from my GPS unit is to help me get where I'm going. What I want the GPS to do is to command the auto pilot. This is why a connection port and data interchange capabilities are "must have" feature for my GPS unit. I also want, at set intervals, to read the vessel position at that time. I write the position on a logbook and/or plot it.
#3 I don't need my GPS unit to tell me where I've been.
If I'm navigating open waters, I want to reverse a route, not backtrack. Using a GPS track can get me into trouble. Accuracy of the track is +/- 33 feet from the track; in a narrow passage, that could be the difference between safe passage and trouble.
I was leaving Pelican Bay one morning when I heard a skipper warning a boat coming out of the bay about their heading and the possibility of running aground. A very calm voice responded to the calling vessel saying not to worry because they were following their track from the previous day. In less than two minutes the boat was aground.
#4 The GPS unit must talk to my computer.
I'm lazy. I don't want to expend lots of time entering waypoints and routes on a tiny keypad. I want to enter all information related to waypoints and routes on my computer and transfer them to the GPS unit. I also want the GPS unit to transfer what it stores to the computer.
Just random thoughts,
Juan.