GPS Diagnostic: Satellite Test 4+

Precise Coordinates & Altitude

David Ryall

Designed for iPad

    • $2.99
    • Offers In-App Purchases



PROMOTION: In-App Purchase is free for next 30 days.


- Essential tool for your iPhone & iPad.
- Test the GPS module.
- Fast GPS lock time.
- Precise navigation parameters.
- Supplements operation of your navigation apps.
- GPS "JumpStart" technology.
- If location cannot be determined then it diagnoses why.
- Assists you in changing conditions to get a reliable location.
- GPS, Galileo, GLONASS, QZSS full support.
- Latitude & Longitude, and WGS84 included by default.
- In-App Purchase: USNG, MGRS, UTM, OSNG, GEOREF, GARS & 174 Datums (free basic functionality).
- **NEW** Smaller footprint (now only 35MBytes)
- Free technical and customer support by email.


- Lodestone Chart™ displays all essential GPS satellite information using a chart with only 4 bars. This dramatically simplifies the diagnostic process (Registered Copyright).

- GPS "JumpStart" technology may resolve GPS problems with third-party navigation applications that have a frozen location, are slow to respond or are performing inaccurately.

- Uses the internal GPS of your iPhone or iPad.

- Includes a Speedometer, Altimeter and Compass.

- Location and altitude ( best-in-class accuracy and reliability )

- Speed (SOG) and Course (COG).

- Heading (i.e. Compass) with ability to turn on and off the manual compass calibration.


This adds additional coordinate systems and datums to the app to let you accurately work with many paper maps and charts used by civilians, U.S. military and NATO forces for walking, sailing, and flying. The coordinate systems and datums included are:

- United States National Grid (USNG)
- Military Grid Reference System (MGRS) -Old and New
- Universal Transverse Mercator (UTM)
- Ordnance Survey National Grid (OSNG) for Great Britain
- World Geographic Reference System (GEOREF)
- Global Area Reference System (GARS)

- 174 Datums (e.g. WGS84, NAD83, NAD27, WGS72, ED50, ED79, OSGB36 etc....).

- The developer is a professional software and hardware engineer working in the satellite space industry. He is a yachtmaster and pilot with a passion for navigation and Apple products.

- Consistent 5 star reviews, see what users are saying:

"Perfect Diagnostic Tool - This is the best app if you need to know the actual status of the internal GPS."
"Great app for kick starting navigation apps - This app finds a position every time and then all other nav apps work."
"Excellent application - This was a much needed application for iOS devices."
“I love the app. It’s been great to have when buying a new phone from eBay to check that the GPS is working. I had to return 3 phones last time before I got one with operational GPS.”
"Awesome, over used term but this app is - This app does what other developers said they could not do."

- Hardware information

- Accuracy of measurements shown for pro users.

- Imperial, metric and nautical units. These are the most commonly used and most useful navigation units. All easily changeable from the screen in use.

- Does not require internet access and does not use cellular data.

- Essential tool for any power user.
(e.g. navigators, yachtsmen, pilots, app developers)

- Share your location by text message, email etc. The format contains all essential information for improved accuracy.

- Works with Garmin Glo.

- GPS Diagnostic™ is a professional GPS test and measurement utility for your iPhone and iPad.

What’s New

Version 3.6

80% reduction in file size to 35MB. Full support for latest iPad Pro 4th Generation.

Ratings and Reviews

4.6 out of 5
446 Ratings

446 Ratings

nefariousn8 ,

Thank God...

Literally one of the most useful apps I have ever used. My iPhone X was having horrible GPS issues under an iOS 11.4 install. I suspected a hardware fault after this app proved the phone was not pulling <any> GPS satellites and was instead relying on cell tower triangulation. After I did all the (failed) usual internet tips of resetting network settings, resetting privacy settings, toggling cell signal, etc. I thought I had proved the hardware fault. Went to Apple store to shove it under their nose. But there was a freak break-in the night before and the store was locked shut. Desperate and dejected, I went back home and decided to do a full wipe and reinstall for giggles, thinking nothing would change. Lo and behold, GPS diagnostic shows multiple satellite tracks after the wipe and reinstall (iOS 11.4). And a full on lock while standing outside using Google maps. Moral of the story: this can’t necessarily PROVE the exact nature of your hardware or software problem, but it can flag for you whether or not your GPS is actively tracking satellites. Knowing is half the battle. From there, it’s up to you to guess and check where your exact problem lies. Still saved my life because there was no other way to get this critical satellite feedback data. Now I don’t have to go to (another) Apple Store tomorrow! 5 stars.

kf6dky ,

Very useful tool if maps act weird.

Used this app to determine that my internal gps antenna/software weren’t functioning correctly. When any mapping software was open they often didn’t seem to accurately display my exact location and any movement shown I was inaccurately spinning or wrong streets or direction etc etc. This awesome little app was extremely useful as it displayed whether I was actually connected to gps satellites and I discovered that I wasn’t. After firmly pressing on my phone where the internal antenna was located would reconnect a loose antenna and viola, a refresh of the app displayed correctly connection and functioning and my navigation apps instantly worked better then I thought they were supposed to to work to begin with. THIS IS AN AWESOME GPS DIAGNOSTICS TOOL and will be a permanent addition to my utilities folder of apps. I cannot say any bad about it at all.

JL-1940 ,

10 Stars! Apple Diagnostics Useless

This App is Fabulous!
Apple refuses to update their Apple Store / Apple Care troubleshooting diagnostics to include ANY GPS Functionality.
If you have such a problem they will tell you that you have No Problem. They will either deny it (Because it passes their tests ) or suggest you buy a new phone (sighting their diagnostics do not find ANY problem with your GPS).
With this diagnostic, I was able to prove the issue to Apple in seconds, but as my phone was out of warranty it was obvious they weren’t going to do anything about it. Tell anyone you know about this diagnostic especially if their phone is under warranty!
In my case I was able to repair the iPhone 6 hardware issue by reconnecting the “F” antenna of which one side had come loose during the defective battery replacement procedure.

App Privacy

The developer, David Ryall, has not provided details about its privacy practices and handling of data to Apple. For more information, see the developer’s privacy policy.

No Details Provided

The developer will be required to provide privacy details when they submit their next app update.

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