GPRS是通用分组无线业务（General Packet Radio Service）的英文简称，是一种新的分组数据承载业务。GPRS与现有的GSM语音系统最根本的区别是，GSM是一种电路交换系统，而GPRS是一种分组交换系统。因此，GPRS特别适用于间断的、突发性的或频繁的、少量的数据传输，也适用于偶尔的大数据量传输。这一特点正适合大多数移动互联的应用。
提供者: KENT BRIGGS { Any navigators out there? I need formulas or source code to calculate the distance between two points given the latitude and longitude of each point. I'm trying to write some support software for my Sony Pyxis GPS (global positioning system). } Procedure Dist( Var xlat1,xlon1,xlat2,xlon2,xdist,ydist,distance : Real); { Returns the distance ( in km ) between two points on a tangent plane on the earth. } Const Km = 111.19; C1 = 0.017453292; Var Xmlat, cosm, Adist : Real; Begin { Dist } { Calculate cos of mean latitude } Xmlat := (xlat1+xlat2)/2; cosm := cos(xmlat*C1); { Calculate Y (N-S) distance } ydist := (xlat2-xlat1)*km; { Calculate X (E-W) distance } xdist := (xlon2-xlon1)*km*cosm; { Calculate total distance } adist := xdist*xdist + ydist*ydist; If adist >= 0 then distance := sqrt(adist) Else distance := 0; End; { Dist }This is one I use in some wind calculations for an aircraft fitted with GPS and LORAN-C.Note that all Latitude And Longitudes are in Degrees with minutes and seconds converted to decimal degrees.
Any navigators out there? I need formulas or source code to calculate
the distance between two points given the latitude and longitude
of each point. I'm trying to write some support software for my
Sony Pyxis GPS (global positioning system). }
Procedure Dist( Var xlat1,xlon1,xlat2,xlon2,xdist,ydist,distance : Real);
{
Returns the distance ( in km ) between two points on a tangent plane
on the earth.
}
Const
Km = 111.19;
C1 = 0.017453292;
Var
Xmlat,
cosm,
Adist : Real; Begin { Dist }
{ Calculate cos of mean latitude }
Xmlat := (xlat1+xlat2)/2;
cosm := cos(xmlat*C1);
{ Calculate Y (N-S) distance }
ydist := (xlat2-xlat1)*km;
{ Calculate X (E-W) distance }
xdist := (xlon2-xlon1)*km*cosm;
{ Calculate total distance }
adist := xdist*xdist + ydist*ydist;
If adist >= 0 then
distance := sqrt(adist)
Else
distance := 0;
End; { Dist }This is one I use in some wind calculations for an aircraft fitted with
GPS and LORAN-C.Note that all Latitude And Longitudes are in Degrees with minutes and
seconds converted to decimal degrees.
gprs应用到gps中是一个大的趋势，据说是费用少，速度快。
但现在市场上好象还没有大规模使用gprs的产品，可能技术和运营方式上还不够成熟吧。
至于编程，我觉得和短信的完全是两码事了。
也或者说gps中使用gprs
读GPS设备串口，通过GPRS返回座标到服务器就是了。
GPRS可以理解成跟拔号连接差不多。