Maxim 2741

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Michael,

One of the goals of Soft OSGPS is to become hardware agnostic.  There are a number of front end chips that are available and while some are easier than others to interface to a USB Dongle I know that Doug Baker has been looking into a number of them.

Generally modifying the carrier and code loops with a larger noise bandwidth and/or changing to a 3rd order loop is required to get high "G" tracking without aiding with an IMU etc.

Best regards,

Cliff

-----Original Message-----
From: Michael Golan
Sent: Aug 12, 2008 6:22 PM
To: opensource_gps@...
Subject: [OpenSource_GPS] Maxim 2741

Hi All,

I'm certain this is no news to you:

 

 

http://www.maxim-ic.com/products/wireless/gps/max2741.cfm

 

The MAX2741 L1-band GPS receiver IC …This dual-conversion receiver downconverts the 1575.42MHz GPS signal to a 37.38MHz first IF, and then a 3.78MHz second IF. An integrated 2- or 3-bit ADC (1- bit SIGN, 1- or 2-bit MAG selectable) samples the second IF and outputs the digitized signals to the baseband processor.

 

 

If I understand correctly, this could be an ideal basis for a USB "dongle" GPS unit which, with osGPS, will provide a unique solution.

 

I'm wondering if anyone has looked into modifying the software to use this unit?

 

I'm specifically interested in running osGPS in a special application (aerobatic aircraft) where 10G or more acceleration generally cause all civilian GPS units to lose tracking… the application is used for pilot feedback, not anything that is mission-critical.

 

At this point, I'm only vaguely familiar with GPS internals, but I believe I can learn the math involved and modify osGPS to feet my special needs (shortening PLL loops to track under high G?) if I have a practical hardware/software solution (on board computer must be Ultra-mobile PC, no moving parts, no PCI card)

 

Many thanks

  Michael Golan

 

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Upon further googling, it appears the Asus U3S notebook contains an optional
built-in GPS based on the Maxim 2741 processor.

See this thread

http://ubuntuforums.org/showthread.php?t=740906

The Philips "spot GPS" software mentioned by maxim is now licensed under NXP
and named swGPS.

Implications as I understand them:

1. There is now a complete standard hardware (PC) which osGPS could
potentially run on

2. This hardware combination has the benefit of an independent software GPS
implementation that we can directly compare with.

3. There are people running non-Microsoft (ie linux) on these machines and
they need an actual working osGPS code (since the swGPS doesn't work on
linux)

I'm read the GPS "software approach" book and hopefully will be able to
figure out what would be required to modified osGPS to use the maxim chip.
Any help would be greatly appreciated.

--Michael




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