gps-time | 易学教程

How can I get the GPS time from the pixhawk, on a “companion computer”

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问题 My project will have two "companion computers" on-board a quadcopter. One will speak to APMCopter autopilot running on a pixhawk, using dronekit python, and the other will communicate with it's peer over ethernet. I'd like both computers to have closely synchronized time, and I'd like them both to be synchronized to the GPS time from the GPS connected to the pixhawk. The documentation for mavlink indicates that there is a "system time" message which includes the GPS time in uSec. How do I

GPS-time in Android

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问题 I'm looking for a way to display GPS-time in my app. What is the easiest way to do this? (It has to be GPS-time due to slight time differences between gps time and internal system time) Thanks 回答1: Whenever you receive a fix from the GPS, the method onLocationChanged is called. The parameter to this method is an instance of Location . One of the methods of this parameter is getTime which will give you what you are looking for. That is if I got right what you are looking for. Read more here

Matching Location.getTime() milliseconds to NMEA sentences

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I get GPS fix times with millisecond precision on my Nexus 7 (sometimes) as well as my Galaxy S3 (almost always). By this I mean the millis are not "000". To make sure this was not fake time resolution introduced by the Android system, I am also capturing the NMEA sentences. And I cannot seem to find where the millis are coming from! First, the Galaxy S3. The fix time is XX.07.55.318 (XX is hours, doesn't matter). You will see this sentence (see below for logs from both Galaxy and Nexus) $GPGGA,140755.3,3920.030827,N,07721.484989,W,1,07,1.5,165.6,M,-42.0,M,,*66 That explains the "3xx" in the

Find nearby users of an app (iPhone and Android)

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问题 I am working on an app that has an iPhone version as well as an Android version. My goal is... display a list of nearby users of my app (iPhone app users and Android app users). Lets say a list users which are currently within 1 mile or 2 miles radius and are currently using my app. This list will display on both apps, iPhone app and Android app. App will update the list when user clicks a Refresh button. My question is... What is the best way to accomplish above stated goal? Do I need to

GPS-time in Android

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I'm looking for a way to display GPS-time in my app. What is the easiest way to do this? (It has to be GPS-time due to slight time differences between gps time and internal system time) Thanks Whenever you receive a fix from the GPS, the method onLocationChanged is called. The parameter to this method is an instance of Location . One of the methods of this parameter is getTime which will give you what you are looking for. That is if I got right what you are looking for. Read more here Getting the GPS time can be rather confusing! To extend discussions in accepted answer, getTime() in

Is it possible to get the atomic clock timestamp from the iphone GPS?

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I'm looking for a reliable way to get the time. It can't be tampered with and it needs to work offline. So no internet time , no user time setup in settings and no BSD uptime time since last reboot. I was wondering since GPS works using atomic clock, whether I could access that information. Thank you JohnK This works to get the GPS time: #import <CoreLocation/CoreLocation.h> CLLocation* gps = [[CLLocation alloc] initWithLatitude:(CLLocationDegrees) 0.0 longitude:(CLLocationDegrees) 0.0]; NSDate* now = gps.timestamp; It doesn't seem to be tamper-proof though. I tried this code on an iPhone 4 in

Android problem finding out how recent latest GPS fix is

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My app uses LocationListener to keep track of the current location. So long as the GPS Provider is providing regular fixes this works well. However, I want my app to alert the user if the location is no longer reliable because the fix is no longer current. I have therefore used a timeCheckHandler to call getLastKnownLocation every few seconds. My problem is that even when accurate fixes are being received frequently the time returned by applying getTime() to the location returned by getLastKnownLocation is generally older than the current time returned by System.currentTimeMillis(), often by

Android problem finding out how recent latest GPS fix is

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问题 My app uses LocationListener to keep track of the current location. So long as the GPS Provider is providing regular fixes this works well. However, I want my app to alert the user if the location is no longer reliable because the fix is no longer current. I have therefore used a timeCheckHandler to call getLastKnownLocation every few seconds. My problem is that even when accurate fixes are being received frequently the time returned by applying getTime() to the location returned by

Is it possible to get the atomic clock timestamp from the iphone GPS?

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问题 I'm looking for a reliable way to get the time. It can't be tampered with and it needs to work offline. So no internet time , no user time setup in settings and no BSD uptime time since last reboot. I was wondering since GPS works using atomic clock, whether I could access that information. Thank you 回答1: This works to get the GPS time: #import <CoreLocation/CoreLocation.h> CLLocation* gps = [[CLLocation alloc] initWithLatitude:(CLLocationDegrees) 0.0 longitude:(CLLocationDegrees) 0.0];