Hi all! First let me say - great community. I'm new in this area so i apologize for some newbie questions that i'm going to ask. I'm a mech. engineer, and i'm managing a project which will have a wireless connected device embedded. I'm not personally designing the wireless device (obviously:), but i would like to know as much as i possibly can. So to make a long story short, my first question is how does rotation of the device (GPRS and GPS) influence signal strength (physical model - imagine a cell phone attached to a 10 cm (4 in) long cord on one end and the other end of the cord is in your hand spinning the phone around 200 rounds per minute) ? Does circularly polarized antenna solves the problem ?
Thank You in advance.
Johnny, GSM and GPS has limitation in speed. If you turn your device then you just have to calculate the velocity
Civil GPS is limited in speed. At GSM you will sooner or later run in trouble with the Doupler effect.
Thank You for the answer Harald.
I have opened two discussions wich i think are pretty similar (my initial ignorance, i apologize) so i will continue only with this one.
In theory circularly polarized antennas would have better performance for my aplication (my conclusion-not neceserrily true:), but in practice, i can't seem to find circ. pol. embedded GSM/GPRS antennas on the market. Are there any ? If not, will linearly polarised antenna work in rotating conditions ?
Thank You ina advance.
Just rotated your mobile phone and see what will happen. If you seach on Google, then you will find hints on speed limitations of GSM /GPRS. GSM is using a parameter called Time Advance. See also http://www.gsm-modem.de/gsm-location.html
You device will move fast, but the TA can be still the same. In my opinion it will work. Just test it with your phone. Set up a voice call and glue a small buzzer to the microphone and then start to rotate.
If you use a smart phone with GPS, then you can do the same. Just write some code that will store the GPS data to the SD card.
|Are you a mobile operator interested in being featured here? Find out how.|