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Tips and questions relating to the GPS modules from SFE
User avatar
By leon_heller
#11743
I've just got a u-blox LEA-4A GPS module working with a PIC 16F88, on home-made PCBs.

Leon
By riaz ahmed
#12340
Dear
I am also working on LEA-4T, But could not understand how to interface it external micrpcontroller. Can you please guide me how to access raw infromation on serial port by using a microcontroller.
Looking forward
riaz
User avatar
By leon_heller
#12344
I connected RxD1 and TxD1 to the corresponding UART output and input on the 16F88. My software detects the NMEA RMC message and puts it into a buffer, so that the time and position data may be transmitted using a GSM modem.

Leon
By NleahciM
#12353
Hi Leon - how is the sensitivity? You don't happen to have any other GPS modules you could compare to? I'm thinking about replacing a GlobalSat EM-406 with a u-blox module due to the better refresh rate.
User avatar
By leon_heller
#12354
NleahciM wrote:Hi Leon - how is the sensitivity? You don't happen to have any other GPS modules you could compare to? I'm thinking about replacing a GlobalSat EM-406 with a u-blox module due to the better refresh rate.
It seems quite sensitive, and works a lot better than a RealTek Sapphire I've got. They make a more sensitive module for use in cities. I don't have any other modules to compare it with.

Leon
By riaz ahmed
#12360
Dear
Thanks for kind reply. My interest is to use UBX protocol to transfer raw data (Timing, psedu, carrier phase, and Doppler) to the external controller (I am planning to uise AT910SAM256* controller). The U-blox has defined configuration messages to access raw infromation. But what I can understand these UBX commands can run from their PC based software. But my problem is to use them in microcontroller's . So I am wondering how to program these UBC configuration messages for AT91SAM256. Could you please help me to clear my undersatnding and any advice for the solution.
Looking forward
riaz
By riaz ahmed
#12413
Dear
Waiting for the kind reply. Sorry if it is bothering. But ur reply will be very hekpfull for me
Thanks
riaz
User avatar
By leon_heller
#12417
You need to download this u-blox Help file:

ANTARIS_Protocol_Specification(GPS.G3-X-03002).chm

which explains the binary ubx commands, they are rather complicated with checksums and so on. I haven't implemented any of them yet; I'm using NMEA for testing my hardware.

Leon
By coyotebush
#13736
If you're interested, I have C++ code for reading raw measurements from the LEA-4T. You can download from www.precision-gps.org. Take a look at src/lib/receivers/rawantaris.cpp.
By TheRidDler
#29446
Hi there! I'm currently working on integrating a LEA-4H gps module into a pre-existing ekg system. The system has a 18f252 pic as well as seperate tx and rx RF modules from Radiometrix. I'm having trouble however connecting the gps UART to the pic. This is my first attempt at anything like this and would really appreciate some help :) Also if anyone has the footprints for the LEA-4H or a Geohelix-SMP antenna that would be gr8! Thnx for all the positive feedback on this forum! I love it..
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