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How sensitive is the GPS in Griduino?


William Rascher
 

I've been using an android phone and have found that it lags behind.  This is especially true when it is mounted close to me in the cup holder and not up on the dash near the windshield.  During contest I travel in a pack to grid corners, so it is useful to know my location down a car length or two.  This is especially true when there is 4 grids in one shopping mall parking lot.  :-)  So how long is the delay between crossing the grid line and the displaying of that information?  Also, how does Griduino mount?

73, William KT5TE


Barry Hansen
 

Good morning William,

Good question and it’s something that really needs testing and some real-world experience. I’d like to hear about real-world experience. Here’s my current understanding.

Sensitivity is excellent, in my experience. That is, the ability to receive satellites is very good. I develop and test the device in my basement and Griduino usually picks up 4 to 6 satellites, or more. I’ll have to bring my Garmin down here for a comparison. There are specs available for the Griduino hardware – Adafruit claims -165 dBm sensitivity (https://www.adafruit.com/product/746) but I doubt if consumer products like Android or Garmin publish comparable figures. Garmin’s sensitivity can be improved with its external antenna support; I haven’t tried it.

Lag in position reports hasn’t exactly been tested. I’m not sure how to test and I’m open to suggestions. The actual lag would depend on the GPS receiver chip’s internals; the remaining hardware in Griduino gets a report every second and displays it immediately. It has no other tasks running as might be found in smartphones.

Accuracy is really the key question for those aiming for the exact grid line or a 4-grid confluence. Although Griduino displays the number of satellites received, which lends a sense of possible accuracy, it doesn’t currently offer a satellite information page readout or accuracy estimate. This will make a good feature improvement for me. In your experience, what GPS receiver is your gold standard for highest accuracy?

Mounting in a vehicle is up to each user and varies widely. It can be mounted like most portable devices. I figure that anyone that can build this kit is resourceful enough to come up with the installation. Personally, I like the ‘Scosche magic mount’ system: put a metal plate on the back of a Griduino (and my Garmin and my smartphone) and attach the adjustable base magnet to the dashboard. It’s easy to add/remove the device de jour. Griduino is not as heavy as my Garmin Nuvi 3590, so there should be lots of options. I’ve attached some photos of how some people have mounted it. The puzzle that I haven’t completely solved to my own satisfaction is where/how to mount the speaker.

Cheers,

Barry K7BWH

 

 

From: Griduino@groups.io <Griduino@groups.io> On Behalf Of William Rascher
Sent: Wednesday, February 03, 2021 5:32 AM
To: Griduino@groups.io
Subject: [Griduino] How sensitive is the GPS in Griduino?

 

I've been using an android phone and have found that it lags behind.  This is especially true when it is mounted close to me in the cup holder and not up on the dash near the windshield.  During contest I travel in a pack to grid corners, so it is useful to know my location down a car length or two.  This is especially true when there is 4 grids in one shopping mall parking lot.  :-)  So how long is the delay between crossing the grid line and the displaying of that information?  Also, how does Griduino mount?

73, William KT5TE