Location accuracy

First, Is this 5th generation iPad a Wifi ONLY model or a Wifi AND cellular data model?

You can find if you have a cellular data pad model by looking at the back of your to see if it has a cellular antenna bar on one side of the back of your iPad and look at onr of the long side edges of your iPad to see if it has a cellular SIM card tray, or not!

You can also check for this in the Settings app to see if your iPad has a Cellular Data settings panel and also by checking out the General settings panel and in the right hand column, scroll down to see if there are panels for Carrier, Cellular number, IMEI, MEID and SEID numbers

A WiFi ONLY iPad has NO accurate GPS functionality and has NO GPS antennas to pickup GPS satellite signals.

If you actually have a WiFi AND cellular data iPad model,

You need to go into the Settings app, under Privacy, tap on Location Services, go down the list of install apps and look for the Navionics app and the Maps app and make sure Precise Location is toggled ON ( green color toggle ) for both of these apps.

You have a WiFi Only model iPad. Mapping Apps, such as Navionics, are critically dependent upon Location Services.

Unlike your iPhone and WiFi & Cellular models of iPad, WiFi Only iPads do not have any GPS location capability with which to directly determine their location - and as such are completely reliant upon their network connection to infer an approximate location. This limitation has further implications in that mapping Apps installed on your iPad cannot estimate your location without a WiFi network connection; no “moving maps” when away from home!

Your approximate geographic location is estimated from a “database lookup” of (a) your WiFi Network Name (SSID) or detected neighbouring WiFi networks - and (b) the “public” IP Address provided by your Internet Service Provider (ISP). 

If the mapped WiFi network name or IP Address are not available within the applicable databases, or if this information substantially differs between sources, then your approximate location may not be computed. This situation often occurs if you are in a remote/rural location where neighbouring WiFi networks are scarce - or if connecting over satellite or VPN connections.

Network IP Addresses and WiFi networks are frequently mapped in urban and cosmopolitan areas (including “crowd source” techniques) and as such approximation of your location from lookup against these databases can be provide relatively high accuracy. As population and network density diminishes, this mechanism becomes progressively less reliable.

If purchased as a Navigation device, I regret that your chosen model of iPad is unsuitable. You need a WiFi+Cellular model.