Billed as a Fitbit for dogs when it hit the market last year, Whistle's compact activity monitor uses a 3-axis accelerometer to monitor Fido's daily exercise. The company has now added GPS capabilities to allow the tracking of location to the device, as well as making it the first consumer product to tap into Sigfox's low-power Internet of Things (IoT) network.

The waterproof WhistleGPS retains the same 38 mm diameter by 10 mm high form factor and all of the features of the original device. The addition of GPS capabilities and connection to the Sigfox network allows users to locate their pet at any time on iOS or Android devices for a monthly subscription of US$5. Whistle says this is the lowest monthly fee of any GPS pet tracker on the market .

The network, which relies on Ultra Narrow Band based radio technology and uses sub-GHz frequencies (902 MHz in the US and 868 MHz in Europe), offers two-way communication at much greater range than Wi-Fi and Bluetooth, but at a lower bandwidth of around 100 bits per second. It is also low power and able to support millions of connections, making it suitable for connecting a wide range of low-bandwidth devices to the IoT ... such as the WhistleGPS.

For the WhistleGPS, this means pet activity and location data from the device can be synched with the company's servers via the Sigfox network, as well as by Bluetooth or Wi-Fi. Whistle says the use of the Sigfox network has also doubled the life of the WhistleGPS' internal rechargeable battery in comparison to its predecessor, with a charge now lasting around a week, depending on usage.

The WhistleGPS is currently available for pre-order in the US, where Sigfox is in the process of rolling out its network, starting around San Francisco. With the help of partners, Sigfox's has already been deployed in France, the Netherlands and Russia, with plans announced for the UK and Spain. The WhistleGPS will be made available to other countries as the Sigfox network becomes available.

Whistle is offering the WhistleGPS for the introductory price of $49 until May 28, with shipping due to commence in the Northern Hemisphere summer of 2015. The price after May 28 will be $129.

The video below introduces the WhistleGPS.

Sources: Whistle, Sigfox