No, you don't have to. If your phone has WiFi and you don't need the real time tracking, you can run this GPS tracking app as WiFi-Only mode. In this mode, this GPS tracking app records location and saves to the device storage. When the device has a WiFi connection, it then uploads the data to the server. Since the device does not have a constant data connection, you will not see the up-to-date location on your map page until it has a WiFi connection.
Please note that the WiFi-Only mode does not work well with Windows Phone 8 or Windows 8 RT devices. The Windows platform has a limitation (in additions to this other limitation
). This GPS tracking app cannot wake up periodically to report location if the device is not connected. In other words, there is no tracking when the device is not connected.
If you need to monitor location real time, then cellular service is required. Cellular service enables this GPS tracking app to upload location as soon as it is recorded.