So the general idea is to get location information ONLY if it is from a GPS source (not WiFi or Cell-Tower). The reason for this isn't really important, for research purposes (and not my research).
If I specify the desiredAccuracy to kCLLocationAccuracyBestForNavigation, it should be using GPS to gather this information. Is it guaranteed, however, that it will use GPS?
I know you can also check the verticalAccuracy property for validity of altitude, which can only be valid if it is from 3D GPS, but does this guarantee that the rest of the information other than altitude is from GPS also?
I posted here on the apple developer program and got a response from an apple employee: https://devforums.apple.com/thread/264712
Even if it's guaranteed to /use/ GPS, it's not guaranteed to /only/ use GPS.
iOS's location subsystem does not provide a way for you to
pick and choose the specific location technology used to satisfy your
request. You will not be able to achieve this goal on the system as
its current architected.
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I've been researching a possible iOS-based app, developed in Unity, that would require a high-degree of positional accuracy (centimeters).
I expect I would need to connect, from the app, to an external GPS device using Bluetooth (or similar) and obtain NMEA sentences (or similar) containing location data.
My research has brought me to RTK, which is extremely accurate. From what I've seen already, it seems that normally GPS receivers which offer this operate themselves at normal GPS precision (2-2.5m). The correction to a high-accuracy location happens in software on a connected computer or tablet with a connection to an NTRIP server.
Assuming what I've said is correct, does anyone know of a GPS device that performs this RTK correction on the GPS device itself? Ideally I could just connect with Bluetooth or similar and get NMEA (or equivalent) data with high-accuracy location.
It may also be that I'm thinking about this incorrectly. On iOS, assuming there is an 3rd party app performing the RTK calculations, is there a standard way to obtain that high-accuracy location? Alternatively, are there GPS vendors that supply SDKs that would allow me to get to where I need to go?
Thanks very much,
Kieran
There is a recent module from U-Blox named ZED-F9P which has internal processing and is faster then RTKLib. Check this blog for performance
You can buy a board like ArduSimple's simpleRTK2B with an XBee module for WiFi/Blutooth or something similar from Sparkfun. You could also wait for the development board from U-Blox which is not yet available.
I know we can access user's location using geolocation in iOS. I want to know what other ways we can access user's location off course with his permission. I also heard we can access user's location using network/Internet etc.
All geolocation of the device is done via the CoreLocation framework. The specifics of what method(s) used to determine the location is not provided through the framework. The position can be determined via WiFi proximity to a known AP, cellular proximity to a tower mapped by the carrier, or most accurately via the GPS system. Not all methods are available on all devices, obviously. Rather than knowing how location was determined, you merely request location within a desired level of accuracy, and the framework will call back and notify you of an update in position. The actual position is not guaranteed to be pinpoint accurate.
I'm getting current location,
In my app I want to know my location is from GPS or WIFI or cellular data. How do I check that ?
Is there any way to determine location source ?
Apple iOS uses
Assisted Global Positioning System (A-GPS)
Crowdsourced Wi-Fi
Cellular network search
to determine your location:
These three stages are used in descending order of priority. In other words, iOS first attempts to fix your location by using a GPS satellite link. If it is unable to acquire a satellite, iOS fails over to Wi-Fi. If you are not connected to a Wi-Fi local area network (WLAN), then iOS uses cell tower data
Apple uses all the non-GPS systems simultaneously with GPS, as part of A-GPS. To say it's falling back is not really an accurate description. Rather, while trying to get a GPS lock, it will use the other systems to get a rough idea of your location. Only if no GPS lock can be obtained, will the phone simply report what it knows from the other sources.
CoreLocation does not provide its source (or sources), but you can use some heuristics to guess.
Check the accuracy reported with location updates. A large range (e.g. 500+ meters) would indicate it's not a GPS fix.
Check which radios are available. If there's no cellular radio in the device, fixes must come from Wifi.
Check if the cellular radio is active. The device does not need service with available providers to use towers for a fix. Don't filter on that.
Those are my best guesses. If you really want this feature, you'll have to experiment.
I need to deliver content with geolocation restrictions, so I need to know exactly what's the physical location of device.
Accordingly to Documentation there is two methods GetCurrentLocale() and
GetCountryCode(), however documentation relays on none of this methods can actually be used to get physical location..
GetCurrentLocale - Returns a string representing the current locale based on the user's language setting ...
GetCountryCode - This does not necessarily match the physical location of the device ...
So my question here is if it's safe to use any of these methods in order to apply geolocation restrictions?
No, you cannot know "exactly what's the physical location" of a Roku. It has no GPS, nor does it do location approximation based on WiFi SSIDs (that would be a privacy no-no).
The APIs you found return codes based on the player setup and are not reliable, since i can reset my player and change the country during new setup. What video services do instead is do geolocation by IP address, there are multiple external services that will help.
How would I go about figuring the position of someone inside (or outside) of a given area (such as a building) using assisted GPS with IOS app?
Is it possible to have it accurate enough withing a few feet?
Is this the right way to go about it?
Is it possible to utilize more than one wifi connection in the calculation?
Your app can use the Core Location framework to determine the device location. Core Location will use whatever hardware is at its disposal to determine the device location to the degree that you request. For example, some devices have WiFi but no GPS; others have WiFi, GPS, and cellular radios. Future devices may have other location technologies built in.
The point is that as an application programmer, you don't worry about that. Instead, you say: "give me a location that's accurate to 100 meters" or "let me know when the device has moved from the current spot by more than 10 meters" or "give me the location with the best accuracy you can manage."
Again, take a look at Apple's Core Location documentation to get a better idea of how it all works.
If you're looking to track a device with, say, 1-meter resolution inside a building, you're not likely to get that from Core Location. There's been research on triangulating position using known locations of WiFi transceivers, but nothing that's implemented in any commercial smart phone that I know of. I don't believe that iOS gives you easy access to the data you'd need to do this, so it's probably not a possibility. You could, however, go the other way: program several WiFi receivers around the building to listen for any nearby devices, use that information to triangulate the devices' positions, and then make that information available via some web service.