/*************************************************************************
*
* SatelliteCalculator v1.0
*
* C. James Callaway, September 17, 2007
* Copyright 2007 C&C Techchnologies, Inc.
*
* satelliteData.js contains the current dataset
*
* Tested against Firefox 2.0.0.6, IE6, IE7, and Safari 3.0.3
*
*------------------------------------------------------------------------
*
* Dataset is an array of SatelliteGroups.
*
* SatelliteGroupObj {
* headers: array(string), // Group headers for table
* satinfo: array(SatelliteInfoObj)
* }
*
* SatelliteInfoObj {
* name: string, // Name of the Satellite
* description: string, // Descriptive entry for Satellite
* satLong: float, // Longitude of the Satellite
* prefix: string, // A unique prefix for elements
* }
*
*------------------------------------------------------------------------
*
*
* satelliteData = [
* {
* headers: [ "1","2","3","4","5","6" ],
* satinfo: [
* {
* name: "INMARSAT 3-F5",
* description: "NET1",
* satLong: 25,
* prefix: 'I3F5'
* },
* {
* name: "INMARSAT 2-F4",
* description: "NET2",
* satLong: 109,
* prefix: 'I2F4'
* }
* ];
* }
* ];
*
*
*
*
*
*
*
*
* calculator = new SatelliteCalculator('tableContainer',satelliteData);
* calculator.calculate({latitude:30,longitude:-92});
*
*
*/
SatelliteCalculator = Class.create();
SatelliteCalculator.prototype = {
initialize:function(tableContainer,satelliteData){
this.data = satelliteData;
this.table = $(tableContainer);
this.suffixes = ['Azimuth','Elevation','Range'];
this.options = {
elevationColorMap:elevationColorMap,
updateDisplay: true
};
this.data.each(this._buildSatelliteGroup.bind(this));
},
calculate:function(inputData){
if (!this._validate(inputData.latitude,inputData.longitude))
return;
var latitude = parseFloat(inputData.latitude);
var longitude = parseFloat(inputData.longitude);
if (this.options.updateDisplay)
this._updateDisplay (latitude,longitude);
this._calculate(latitude,longitude);
},
_buildSatelliteGroup:function(satelliteGroupData){
this.table.appendChild(
this._buildRow('TH',satelliteGroupData.headers)
);
satelliteGroupData.satinfo.each(this._buildSatelliteRow.bind(this));
},
_buildRow:function(elementType,cells){
var row = document.createElement('TR');
cells.each(function(cell){
var cellElement = document.createElement(elementType);
cellElement.appendChild(document.createTextNode(cell));
row.appendChild(cellElement);
});
return row;
},
_buildSatelliteRow:function(sat){
var row = document.createElement('TR');
row.id = sat.prefix + "Row";
var str = Math.abs(sat.satLong).toString()
+ entity("°") + " " + ((sat.satLong < 0) ? "W" : "E");
[ {name:sat.name,textAlign:'left',nodeType:'TD'},
{name:str,textAlign:'center',nodeType:'TD'},
{name:sat.description,textAlign:'center',nodeType:'TD'}
].each(
function(r){
var textNode = document.createTextNode(r.name);
var cell = document.createElement(r.nodeType);
cell.style.textAlign = r.textAlign;
cell.appendChild(textNode);
row.appendChild(cell);
});
this.suffixes.each(
function(suffix){
var textNode = document.createTextNode(' ');
var cell = document.createElement('TD');
cell.id = sat.prefix + suffix;
cell.style.textAlign = 'center';
cell.appendChild(textNode);
row.appendChild(cell);
});
this.table.appendChild(row);
},
_updateDisplay:function(latitude,longitude){
$('latitudeDisplay').update(latitude);
$('longitudeDisplay').update(longitude);
},
_calculate:function(latitude,longitude){
this.latitude = latitude;
this.longitude = longitude;
var _this = this;
this.data.each(
function(group){group.satinfo.each(_this._updateRow.bind(_this))})
},
_updateRow:function(sat){
var elms=[
sat.prefix+"Azimuth",
sat.prefix+"Elevation",
sat.prefix+"Range"
];
var rowName = sat.prefix+"Row";
elev = elevation(sat.satLong,this.latitude,this.longitude);
this._updateRowColor(rowName,elev);
$(elms[0]).update(azimuth(sat.satLong,this.latitude,this.longitude) + entity("°"));
if (elev<=0) elev = "<0";
$(elms[1]).update(elev + entity("°"));
$(elms[2]).update(satelliteRange(sat.satLong,this.latitude,this.longitude));
},
_updateRowColor:function(element,elevation){
element=$(element);
if (this.options.elevationColorMap){
var colors = this.options.elevationColorMap(elevation);
element.setStyle({ backgroundColor: colors.backgroundColor,
color: colors.color});
}
},
_validate:function(latitude,longitude){
latitude = parseFloat(latitude);
longitude = parseFloat(longitude);
if (isNaN(latitude)
|| isNaN(longitude)
|| latitude==null
|| longitude==null
|| latitude<-90
|| latitude>90
|| longitude<-180
|| longitude>180
|| latitude.length==0
|| longitude.length==0){
alert("\nPlease Enter your C-Nav GPS Receiver Position in degrees of Latitude and Longitude (decimal)");
return false;
}
return true;
}
};
function azimuth(satLongitude,latitude,longitude) {
if (satLongitude==longitude && latitude==0) return 0;
lon_delta=(longitude-satLongitude);
if (lon_delta<-180) lon_delta=360+lon_delta;
if (lon_delta>180) lon_delta=360-lon_delta;
radian_lon=lon_delta/57.29578;
comp_azumith=180+(57.29578*Math.atan(Math.tan(radian_lon)/Math.sin(latitude/57.29578)));
if (latitude<0) comp_azumith=comp_azumith-180.0;
if (comp_azumith<0) comp_azumith=comp_azumith+360.0;
if (lon_delta<-90) comp_azumith=comp_azumith-180.0;
if (lon_delta>90) comp_azumith=comp_azumith+180.0;
comp_azumith=(Math.round(comp_azumith));
return comp_azumith;
}
function elevation(satLongitude,latitude,longitude) {
radian_lon=(longitude-satLongitude)/57.29578;
radian_lat=latitude/57.29578;
d=1+35786/6378.16;
a=d*Math.cos(radian_lat)*Math.cos(radian_lon)-1;
b=d*Math.sqrt(1-Math.cos(radian_lat)*Math.cos(radian_lat)*Math.cos(radian_lon)*Math.cos(radian_lon));
interim_elev=57.29578*Math.atan(a/b);
if (interim_elev<30)
comp_elevation=(interim_elev+Math.sqrt(interim_elev*interim_elev+4.132))/2
else
comp_elevation=interim_elev;
comp_elevation=(Math.round(comp_elevation));
// if (comp_elevation<5) comp_elevation="< 5";
return comp_elevation;
}
function satelliteRange(satLongitude,latitude,longitude) {
radian_lon=(longitude-satLongitude)/57.29578;
h=35786*35786;
o=2*6378.16*(35786+6378.16);
a=1-Math.cos(latitude/57.29578)*Math.cos(-radian_lon);
comp_distance=Math.sqrt(h+o*a);
comp_distance=Math.round(comp_distance);
return comp_distance;
}
function entity(str,stupefy){
var
e=document.createElement("div");
e.innerHTML=String(str);
if (stupefy)
return '&#'+e.innerHTML.charCodeAt(0)+';';
return e.innerHTML;
}