This is the first popup you should see. There are two options available: COM 1 and COM 2. These are the serial ports of your computer. Depending on which serial port you selected, choose the correct option. If you are not sure, choose COM 1, and later, if the program refuses to work, simply restart the program, and choose COM 2. Then hit OK. If the program opens, and you receive another pop-up that says "Unable to determine receiver type. Please select one of the following: ", then your antenna does not have a clear view of the sky, or the serial port was not inserted properly. Once the program is open, you will see many things happen at once. This is perfectly normal. The next section describes each portion of the program you see, and an explanation of their purposes or meanings.
Timing is the portino of the program that describes the current time, date, GPS week, and TOW. time and date are obvious. TOW is time of week, or the time in seconds since the last sunday recorded. GPS week is the week since the implementation of widespread GPS use, or the evening of 05 January 1980 / morning of 06 January 1980. These two are not terribly important. Timing is very accurate, as it is taken from atomic clocks run by the Department of Defense, as is the date. Timing is automatically calibrated by the GPS, so there is no need to enter the time at any point, as long as your antenna has a clear view of the sky.
The ENU velocity is the velocity in the east, north, and up coordinates. This is useful if you wish to be able to project the path of the Weather balloon. With east, west, and up velocities, one can discover how fast the balloon (or other object carrying the GPS system) is moving and in what direction(s). Although this option may be a helpful one, it is not included with the TAIP or NMEA 0183 languages. It is only the output of the TSIP language. However, NMEA 0183 offers ground speed and TAIP offers Up Velocity. Though these aren't as comprehensive as what the TSIP offers, they can still be used to track the object carrying the GPS unit.
The change in position section describes the change the unit has experienced since the last recorded measurement. This means that if you leave the GPS unit in one place to calibrate itself and explore the surrounding area, it will record that position. When you move it, the change in position describes how far and in what directions you have moved. Though not particularly useful, it is an interesting process to watch.
To configure the position output, click Configure on the menu bar. Scroll down to I/O options. This should give you a pop-up that looks like this. Under Output Format, click on the LLA option, which is Latitude, Longitude, and Altitude. XYZ ECEF is another option. The Cartesian coordinate frame of reference used in GPS/GLONASS is called Earth-Centered, Earth-Fixed (ECEF). ECEF uses three-dimensional XYZ coordinates (in meters) to describe the location of a GPS user or satellite. The Z-axis pierces the North Pole, and the XY-axis defines the equatorial plane. Either way, ENU is easier to understand at first.
Under LLA Altidue Output, click HAE(datum). This uses an ellipsoid mathematical curve to predict the satellite's position, and therefore the altitude of the GPS unit. Under Velocity, click ENU. Under Precision of Output, click double. This increases the precision, as single does nto contain as many decimal points as double. Under Altitude Input, click HAE(datum). For Timing, either option is fine. Datum, if you do not choose an option, will automatically choose the first option, which is WGS-84. WGS 84 is an earth fixed global reference frame, including an earth model. It is defined by a set of primary and secondary parameters: the primary parameters define the shape of an earth ellipsoid, its angular velocity, and the earth mass which is included in the ellipsoid reference the secondary parameters define a detailed gravity model of the earth. This means that it is essentially a reference point for the GPS unit. After you have finished configuring the options, simply click apply, then OK. After coordinating all this, you should see Longitude, Latitude, and Altitude listed in the boxes under Position. Altitude is described as meters above sea level. This is one of the most important areas of the program, and should be taken into consideration.
The Mode portion describes essentially the appropriate number of satellites the GPS unit has found. Here is a list of al the modes the system operates in.
2-D GPS mode-A procedure of determining a 2-D position using signals received from the best (or only) three available GPS satellites. Altitude is assumed to be known and constant. A 2-D position solution will only be determined if signals from three or more satellites are available. 2dRMS-Twice the distance root mean squared. The error distance within which 95% of the position solutions will fall. 3-D- Three Dimensional. A 3-D position is defined as latitude, longitude, and altitude. 2-D-Two Dimensional. A 2-D position is defined as latitude, longitude, and altitude. 3-D GPS mode A procedure of determining a 3-D position using signals received from the best (or only) four available GPS satellites. A 3-D position solution will only be determined if signals from four or more satellites are available. The last mode is the most optimal. It is preferred to any of the other modes.
Health, when optimal, should read "Doing Position Fixes." This means it has gathered enough satellites to do its job. Otherwise, it reads something along the lines of "Only one/two/three satellites detected." DGPS should read Auto, unless you wish to change the mode. The next four options have little circles by them: BBRAM, Antenna, RTC, and Almanac. To start off with, one should be lit green. The rest should still be yellow. Green means everything is working fine. If you set the antenna up correctly, and it has a clear view of the sky, then it should be the only one green. After the system checks its BBRAM(Battery Backed Random Access Memory), then that should turn green as well. Real Time Clock should turn green soon thereafter. However, the Alamanac takes much longer. It needs at least 15 minutes out in a clear open area with no interruptions before it turns green. When it has collected enough information about the world's coordinate systems, then it has updated its alamanac. When the system is functioning properly, everything should be green.
Satellite data is a visual representation of the satellite tracking process. The first column is SV, or satellite vehicle. It tracks the available satellites in the sky. When the boxes light up green, it means those satellites are currently being tracked. The more green there is, the more satellites are being used to provide the information seen in the other boxes. AMU describes the signal strength of the satellites. It is a unit of measurement. Az means Azimuth. The azimuth of an object is the angular distance along the horizon to the location of the object. By convention, azimuth is measured from north towards the east along the horizon. Elev is elevation, which gives the elevation of the satellite. The satellites are cycled and recycled whenever their signal gets stronger or weaker. Simply put, all you need to see is in the first column. The more green, the more sucessful the unit was in tracking satellites.
DOP is short for dillution of position. It is a margin of error. It gives leeway for how accurate the position is. One can use it to determine whether the values gathered by the GPS unit are usable or too inaccurate to be considered.
HDOP is the horizontal dilution of position, or the measure of how well the position of the satellties used to generate longitude and latiude, are arranged. The general rule of thumb is that when the DOP values are less than four, they are the best. Between four and eight, the values are okay, and greater than eight, the values are poor.
VDOP is the vertical dilution of position, or the measure of how well positions of satellites, used to generate vertical component of a situation, are arranged.
TDOP is the time dilution of precision, or how a satellite's geometry is affecting the ability of the GPS to determine time.
PDOP is the positional dilution fo precision, or the measure of the overall uncertainty wit TDOP not included in estimate. PDOP is calculated by finding teh square root of the HDOP squared plus the VDOP squared.
GDOP is the geometric dilution of precision, or the measure of the overall uncertainty of the GPS solution. This isn't included in the program, but it is good to know. Calculations can be made on your own, given the information the program provides. TDOP is included. GDOP is the square root of the TDOP squared plus the HDOP squared plus the VDOP squared, or in simpler terms, the square root of the PDOP squared plus the tDOP squared. This value should be less than 5.
This wraps it up for the TSIPMonitor32 program. An in-depth look at the TSIPCHAT program is coming up.