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GPS update rate for latest 1616 product

Posted: Sat Aug 06, 2022 7:48 pm
by adasamuelmills
I have the data sheet for the device. UART rx only input at 9600 baud.

I have a pico with a pimoroni unicorn for the display. So it is difficult to use circuit python.

Using Thonny as the python tool. I am not getting 10Hz updates. I assumed this would be the standard but apparently as the data sheet states it is the "maximum"

How do I get 10 Hz updates outside of circuit python? There is no register description or any other setup information in the datasheet so it powers up and does as it pleases as far as the UART messages which I can see. I am reading a UART buffer that is 210 characters long and can see all the NMEA messages. In between outputs I am printing the real time clock. The rate of the loop is optimally 10 Hz. When the read is empty the print for the 210 buffer is "None" so it is emptying. I do not know the buffer depth however for the pico hardware UART.

None
(2022, 8, 6, 5, 18, 29, 52, 0)
b'$GPGGA,232953.000,3441.9802,N,08647.5142,W,2,08,1.04,206.5,M,-30.3,M,,*5E\r\n$GPGSA,A,3,10,32,23,22,24,31,25,12,,,,,1.35,1.04,0.86*0F\r\n$GPRMC,232953.000,A,3441.9802,N,08647.5142,W,0.15,54.37,060822,,,D*44\r\n'
(2022, 8, 6, 5, 18, 29, 53, 0)
None
(2022, 8, 6, 5, 18, 29, 53, 0)
None
(2022, 8, 6, 5, 18, 29, 53, 0)
None
(2022, 8, 6, 5, 18, 29, 53, 0)
None
(2022, 8, 6, 5, 18, 29, 53, 0)
None
(2022, 8, 6, 5, 18, 29, 53, 0)
None
(2022, 8, 6, 5, 18, 29, 53, 0)
None
(2022, 8, 6, 5, 18, 29, 53, 0)
b'$GPGGA,232954.000,3441.9802,N,08647.5143,W,2,08,1.04,206.5,M,-30.3,M,,*58\r\n$GPGSA,A,3,10,32,23,22,24,31,25,12,,,,,1.35,1.04,0.86*0F\r\n$GPGSV,3,1,12,10,74,077,33,32,64,327,19,22,49,285,30,23,44,116,28*7B\r\n$GPGSV,'
(2022, 8, 6, 5, 18, 29, 54, 0)
b'3,2,12,44,38,225,29,31,30,208,27,25,23,118,21,21,23,309,16*72\r\n$GPGSV,3,3,12,12,18,078,27,24,15,044,19,01,05,326,15,18,03,166,16*7B\r\n$GPRMC,232954.000,A,3441.9802,N,08647.5143,W,0.16,54.37,060822,,,D*41\r\n'
(2022, 8, 6, 5, 18, 29, 54, 0)
None
(2022, 8, 6, 5, 18, 29, 54, 0)
None
(2022, 8, 6, 5, 18, 29, 54, 0)


Therefore the message content needs to be reduced for the rate to go up at a minimum, as this many characters is around 5.714Hz

The USB is the source of the "prints" so it is not too slow.

Re: GPS update rate for latest 1616 product

Posted: Sun Aug 07, 2022 12:26 pm
by adasamuelmills
Well, ha, I got locked on the data sheet for the hardware and did not notice the packet data sheet above it.... why I am a hardware guy.... DOH

Anyway I will try to set some of the parameters to new values and see what happens!

WIll update

Re: GPS update rate for latest 1616 product

Posted: Sun Aug 07, 2022 12:36 pm
by Franklin97355
Thanks. Please let us know how you are doing and if you could, can you let me know what product you got? There are several.

Re: GPS update rate for latest 1616 product

Posted: Sun Aug 07, 2022 2:54 pm
by adasamuelmills
PRODUCT ID: 746

yes I have it all working at 10Hz now

by restrict message to GPGGA
set baud rate to 38400
disable easy mode
set rate

THIS IS AWESOME!

Re: GPS update rate for latest 1616 product

Posted: Sun Aug 07, 2022 4:48 pm
by adasamuelmills
Ok, so often I am not getting a fix it does not have an external antenna, is that required normally?

Re: GPS update rate for latest 1616 product

Posted: Sun Aug 07, 2022 9:44 pm
by Franklin97355
Are you using it outside? Buildings block the signal and an antenna would help but will add bulk unfortunately.

Re: GPS update rate for latest 1616 product

Posted: Sun Aug 07, 2022 11:22 pm
by adasamuelmills
Inside a normal house... nothing special as far as lots of metal

Re: GPS update rate for latest 1616 product

Posted: Mon Aug 08, 2022 1:10 pm
by Franklin97355
I would try outside before you give up on it.

Re: GPS update rate for latest 1616 product

Posted: Mon Aug 08, 2022 1:30 pm
by adasamuelmills
yeah I am not disappointed... just inexperienced. I read alot of times the TTFF? is around mid 30seconds, so that gave me better confidence, that is pretty much in house performance. Just now I confirmed outside that gets halved depending on orientation and other things. For my needs I will likely want an antenna tho.

Re: GPS update rate for latest 1616 product

Posted: Mon Aug 08, 2022 7:55 pm
by dlleigh
Outdoors under an unobstructed sky is definitely the proper test for a GPS receiver. Testing inside is a compromise situation involving too many variables, and is too likely to cause you problems.

The GPS in mobile phones tends to lock quickly and operate well indoors, but it is "assisted" and gets information over the phone network that allows it to operate better than a standalone GPS unit will.

Re: GPS update rate for latest 1616 product

Posted: Mon Aug 08, 2022 9:11 pm
by adasamuelmills
yup THanks!