(And, see also some works on GPS relplay
I did a simple experiment on ADS-B. See attached picture for principle.
And video here: http://youtu.be/xpLDqBkUiKc
In China, see here: http://v.youku.com/v_show/id_XNzE4NzIzNDIw.html
You can get GRC for replay here: https://github.com/JiaoXianjun/GNSS-GPS-SDR/tree/master/adsb
But I need your attention!!! if you want do some experiments.
Transmit at 1090MHz is dangerous if you are not authorized!
Do not transmit at 1090MHz!
Select legal frequency and legal/low-enough power to transmit very locally for example in a basement or chamber/room via a close-loop RF cable.
Make sure you are not interfering any other systems!
Have fun with safety.