Gps serial data

The device or file is specified with the -f parameter. This includes the debugging flag, -D9, so we will get lots of extra information to help confirm that the transfer is operating correctly. Unzip it, and then connect the serial to USB adapter. The "Add New Hardware" wizard will likely see the new device. Give the wizard the location of the file that you downloaded and follow the instructions. Create a new connection using com3 and setting the speed to bits per second.

You should then start seeing NMEA sentences. Follow Us. February 4, - By Eric Gakstatter. N denotes north latitude. W denotes west longitude. M denotes units of altitude eg. Meters or Feet M denotes the units used by the geoidal separation. Top Ten King February 6, usanews. Andrew Watson says:. February 4, at pm. Dozens of GPS satellites, all containing extremely accurate atomic clocks, have been launched since the late 70's, and launches continue to this day. The satellites continuously send data down to earth over dedicated RF frequencies.

Our pocket-sized GPS receivers have tiny processors and antennas that directly receive the data sent by the satellites and compute your position and time on the fly. Simply amazing. There are some concepts that this tutorial builds upon and that you may need to know or prepare before starting:. GPS receivers use a constellation of satellites and ground stations to compute position and time almost anywhere on earth.

Notice the moving point on the globe and the number of visible satellites. At any given time, there are at least 24 active satellites orbiting over 12, miles above earth. The positions of the satellites are constructed in a way that the sky above your location will always contain at most 12 satellites.

The primary purpose of the 12 visible satellites is to transmit information back to earth over radio frequency ranging from 1. With this information and some math, a ground based receiver or GPS module can calculate its position and time. The data sent down to earth from each satellite contains a few different pieces of information that allows your GPS receiver to accurately calculate its position and time.

An important piece of equipment on each GPS satellite is an extremely accurate atomic clock. In other words, the GPS module receives a timestamp from each of the visible satellites, along with data on where in the sky each one is located among other pieces of data.

From this information, the GPS receiver now knows the distance to each satellite in view. This is also called a lock or a fix. Did you catch all of that? If not or if you want more, check out a much more detailed explanation, in volume 1 of GPS Fundamentals by Dan Doberstein.

Volume 1 has been released for free, but you must support the author to read volume 2. An artist's rendition of the control segment. Along with satellites and GPS receivers, there are ground based stations that can communicate with the satellite network and some GPS receivers. This system is formally called the control segment and increases the accuracy of your GPS receiver.

DGPS units are also expensive and tend to be larger because they require an additional antenna. GPS Accuracy depends on a number of variables, most notably signal to noise ratio noisy reception , satellite position, weather and obstructions such as buildings and mountains.

These factors can create errors in your perceived location. Signal noise usually creates an error from around one to ten meters. Mountains, buildings and other things that might obstruct the path between the receiver and the satellite can cause three times as much error as signal noise.

A GPS receiver must be able to get a lock on 4 satellites to be able to solve for a position. The first lock it gets allows the receiver to obtain the almanac information and thus what other satellites it should listen for. Although it is possible to get a position from less than 4 satellites, the margin of error of this position can be rather large. Your most accurate read of your location comes when you have a clear view of a clear sky away from any obstructions and under more than four satellites.

To combat these errors, a couple of different assistants have been created. This method uses wireless ground-based networks to help relay between the satellite and the receiver when the GPS signal is weak or not able to be picked up. There are two ways AGPS can help out. The first is to provide the receiver with the proper almanac data and the precise time.

The second utilizes the higher computing power and good satellite signal of the ground base to interpret the broken or fragmented information the receiver is receiving to provide a more accurate position reading to the receiver. When communicating with these receivers, the GPS can acquire a lock on the satellite more quickly as well as receive more accurate information.

But AGPS is present in more devices than just cellphones; it's even available in cameras and some vehicles. DGPS also uses ground or fixed GPS stations to determine the location, but differs in that it finds the difference between both the satellite and the ground location reading.

These ground stations may be up to nautical miles from the receiver, and it is important to note that accuracy deteriorates the further you are from the ground station. DGPS is accomplished by a ground station broadcasting a signal which dictates the error between the actual pseudorange and the measured pseudorange.

This value is calculated by multiplying the speed of light by the time it takes the signal to travel from the satellite to the receiver. WAAS holds a specific set of accuracy standards that ground station measurements must meet. Laterally and vertically, WAAS must be accurate to within 7. These ground stations send their measurements to master stations which send the corrections to WAAS satellites every 5 seconds or quicker.

From the Satellite, a signal is broadcast back to the receivers on earth where the corrections are used to improve the GPS accuracy. In some locations, WAAS is able to provide an accuracy of 1 meter lateral and 1. GPS data is displayed in different message formats over a serial interface. The delay can be calibrated out. The minimum NMEA sentence requirements matter. If you like VisualGPS and would like to support more products like these, please donate.

Currently VisualGPS is over 10 years old! VisualGPS Freeware incorporates many advanced features found in professional programs. Its sole purpose is to display graphically specific NMEA sentences and show the effects of selective availability SA. Download a free copy of VisualGPS program.

It is a 32 bit program written for both the Windows , XP and Vista environments. This software is freeware and cost is free.

Tools such as a survey utility average the position and shows accuracy of the GPS receiver in a static application. Other features such as analog gauges show altitude, speed, vertical speed and direction. One additional feature is the capability to connect and share a GPS receivers data over the Internet. ClockMaze is a simple screen saver that creates a maze, solves it, and shows the current time. You can set up items such as solve color, maze color, and solve speed.

It's free.