Smallest GPS sensor

Hi,

I am designing animal tracker based on GPS + LoRa network. Want to stick with minimum power consuming GPS chip to have at least 3 months of battery life.

Initially I thought of using Semtech LR1110, but with this I need to use Semtech cloud API to get the accurate location from raw data. I thought proper GPS chip would give me accurate location without calling third party API's

What are the option I have it here ?

Update : Expecting to get GPS reading every 5 min interval.

GPS modules are all relatively power hungry. Consequently, the battery life will depend almost entirely on what fraction of the time the GPS module is turned off, not on the power consumption while on.

What battery do you intend to use, and what is your overall plan for the on/off ratio?

If you haven't already, research commercial trackers like SPOT Trace, where the manufacturer has really bent over backwards to ensure the longest possible battery life. Several operating options are provided to take into account the tradeoffs.

This is quite small:

DaveEvans:
This is quite small:

https://www.lotek.com/products/pinpoint-gps/

... assuming you know that a US dime is roughly 1.8cm in diameter!

Don

rp346:
Hi,

I am designing animal tracker based on GPS + LoRa network. Want to stick with minimum power consuming GPS chip to have at least 3 months of battery life.

Initially I thought of using Semtech LR1110, but with this I need to use Semtech cloud API to get the accurate location from raw data. I thought proper GPS chip would give me accurate location without calling third party API's

What are the option I have it here ?

Update : Expecting to get GPS reading every 5 min interval.

There is a report here, that collates the performance of a range of GPSs and gives typical battery life based on a 10 minute transmission cycle, using LoRa;

GPSs are power hungry devices, there is no magic wizard way of cutting power consumption, the Quectel L70 and Ublox SAM M8Q are the lowest power GPSs I have found at 13.6mAhr and 12.12mAhr per day respectivly.

The key to long battery life for GPS powered projects is the ability of the GPS to quickly get a fix when powered up (hot fixing). The power consumption of a GPS when powered off is of little consequence since most GPS in backup mode consume only 8uA or so. However the reality is that hot fix times varies considerably, as the report mentioned above shows.

A 3 month battery life is easy peasy, just use a big enough battery ............................

On a general note on LoRa trackers;

Solutions based on LoRaWAN and similar ‘cloud’ based systems do require that the transmitter is within range of a gateway, so this type of solution might well work for tracking domestic pets in a city such as Amsterdam (where there are heaps of gateways) but go outside the confines of Amsterdam and gateway coverage will be sparse and in a lot of places in the World, non-existent.

There is this new module from Kolmostar, declared "ultra low power", but the advertising is deceptive to the point of downright ridiculous.

Power consumption is presented in terms of milliJoules per fix, which if you do the math (assuming 1 second to fix, as advertised), suggests that the module consumes about 10 mA. So it is certainly NOT "ultra low power".

And they fail to make clear that the module has to update its ephemeris every 12 hours, which is a terrible drawback for something like an animal tracker.

In addition that Kolmostar module is;

"A-GPS via LPWAN to further minimize power and TTFF"

I presume that means its assisted GPS, and the ephemeris data (for the location) comes from a nearby Internet connected LoRaWAN Gateway which knows where it is.

Handy perhaps if the 'GPS' is used in the few places that are close to LoRaWAN gateways, i.e. locations like Amsterdam.

Some of the wild bird trackers log position at regular intervals , then send a txt message when they come into range of a phone network . Might be a solution?

I started working on a module based on the LR1110 (hackaday project link) if you're looking for a more usable form-factor for that part.

It's certainly very low power and capable, but admittedly the lowest power is only achievable when you've got a LoRaWAN connection.

Sensors:
I started working on a module based on the LR1110

I suspect it will be a while before there is an Arduino library for the device ..........................

srnet:
I suspect it will be a while before there is an Arduino library for the device ..........................

That's the next step for the project!