Compass   

Cold Start and Warm Start  

GPS channels  

How GPS Receivers Work?  

Latitude and Longitude 

Magnetic Poles & Magnetic Declination

Map & Charts 

Map Scale

Map Legends

Routes

Topographic Map

WAAS (Wide Area Augmentation System)  

Waypoint

What Is Global Positioning System?

UTM and UPS

What Is Global Positioning System?

The Navstar Global Positioning System (GPS) is a space-based radio positioning and time transfer system. GPS provides accurate position, velocity, and time information to an unlimited number of suitably equipped ground, sea, air and space users. GPS comprises three major system segments, Space, Control, and User.

The Space Segment consists of a operational constellation of 24 Navstar satellites. Each satellite broadcasts RF ranging codes and a navigation data message, and contains multiple atomic clocks that contribute very precise time data to the GPS signals. 

The Control Segment consists of a network of monitoring and control facilities which are used to manage the satellite constellation and update the satellite navigation data messages. 

The User Segment consists of a variety of radio navigation receivers specifically designed to receive, decode, and process the GPS satellite.  GPS receivers decode these signals, effectively synchronizing each receiver to the atomic clocks. This enables users to determine the time to within 100 billionths of a second, without the cost of owning and operating atomic clocks.  

For GPS positioning, a minimum of four satellites is normally required to be simultaneously "in view" of the receiver, thus providing four range measurements. This enables the receiver to calculate the three unknown parameters representing its (3-D) position, as well as a fourth parameter representing the user clock error. Treating the user clock error as an unknown enables most receivers to be built with an inexpensive crystal oscillator rather than an expensive precision oscillator or atomic clock. Precise time estimates are required for precise positioning, since a time error of 3 nanoseconds is roughly equivalent to a range error of 1 metre. A receiver can use less than four satellites if time or altitude is precisely known or if these parameters are available from an external source.

WAAS (Wide Area Augmentation System):

 The WAAS, a satellite-based augmentation system operated by the U.S. Federal Aviation Administration (FAA), provides aircraft navigation for all phases of flight. Today, these capabilities are broadly used in other applications because simple receivers without additional equipment can process their GPS-like signals.

Waypoint:

 A point along your way, that is if a location is an important, impressive or beautiful location for you, then you can set it as a waypoint and GPS will store the exact location in memory in whatever coordinate format you chose.  

Routes:

is a series of waypoints that you connect together to create a travel route.

Map & Charts 

A map is projection of three-dimensional curved globe into a two dimension flat surface. A map of small area which curvature of surface does not make a factor is called a plan. Projection of a large area such as north hemisphere into a plane surface, which curvature of original surface is a factor, is called a map or chart for navigational purposes. 

Map Scale

Map scale is the ratio of actual size to the corresponding size in the map. All maps indicate their scale in a legend. Scales are shown by two numbers, the first is map distance, and the second one is the actual distance on the ground. Map distance is always one unit. A scale of 1:250,000 mean that 1 unit on the map equals to 250,000 of the same units in real world.

Map Legends

The specific information about the area, which maps covers, is indicated in legend. The major features are: Map name, Year of production, Map scale, Distance scale, Magnetic declination, Latitude and Longitude, and UTM coordinates. 

Latitude and Longitude 

Latitudes are hypothetical circles perpendicular to Earth rotation around its axes. Equator which divides northern and southern hemispheres is considered to be 0 degree latitude. Points north of equator are referred as north latitudes and points south of equator are referred to as south latitudes. Longitudes are hypothetical circles running from North Pole to South Pole. All the circles are at same size and also called meridians by convention, the circle running through Greenwich, England in called Prime meridian or 0 degree Longitude. The points east of prime meridian go from 0 to 180 degree east, and points west of prime meridian go from 0 to 180 degree west. 

UTM and UPS

UTM stands for Universal Transverse Mercator System and UPS stands for Universal stereographic System. U.S Army Map Services devised these two systems. UTM is a metric system and the unit of distance is meter. In UTM system, the world is divided to sixty zones the run from North Pole to South Pole, each covering 6 degrees wide in longitudes. These zones are numbered from 1, which covers 180 and 174 west to 60, which covers 174 to 180 east. Each zone divided to horizontal bands spanning 8 degrees of latitudes. The letter C-M specifies latitudes south of Equator and the letters N-X specify latitudes north of Equator. This is where you can find more information about UTM The Universal Transverse Mercator Grid 

Here is the site you can download GEOTRANS (Geographic Translator) is an application program which allows you to easily convert geographic coordinates among a wide variety of coordinate systems, map projections, and datum.

 Compass 

Compass is a device, which shows direction of magnetic poles, it consists of a magnetic needle, which rotates freely on a pivot. Even if you have GPS unit, which shows North and South direction, carrying a compass is recommended. Here at the compass store, you can find how to use a compass.

How GPS Receivers Work? 

At these kinds of maps, contours are used to represent three-dimensional geographic terrains at two-dimensional paper. Contour lines are drawn on the map as points of the same height above sea level.    

Magnetic Poles & Magnetic Declination