Hello Harald, On Sun, 12 Dec 2010 17:01:22 +0100, "Harald Welte" <laforge(a)gnumonks.org> wrote: I don't think that implementing is the hard part, debugging is. You send data which might be wrong due to some bugs in your code into a "black-box" which does something with the data. The "black-box" will not tell you if your data are wrong, if they are, it might just take longer till any results are returned. So you are not sure if you are doing the things right. I conclude the above from my experience so far: Even phones with very extensive tracing capabilities don't tell you much about what is going on during their GPS position calculations. And at least I am not aware of a GPS server I have access to who will provide those data required for an "MS-assisted" measurement so that one could compare the own calculation against a reference. If someone know about a server providing those data (I am not talking of things like "almanac" or "ephemeris" here) or knows about existing source code to do the calculation, I would like to know. BTW, the book "Server-Side GPS and Assisted-GPS in Java" contains a few nice chapters, one should not care about "Java" in the title, only the examples are written in Java. Best regards, Dieter -- Dieter Spaar, Germany spaar(a)mirider.augusta.de