Ios CLLocationManager响应性

我有一个应用程序，它围绕着设备的GPS和来自它的信息。位置数据必须准确且最新，这一点很重要。我知道该设备受到GPS和GPS的限制，但我想知道我是否可以做些什么来调整/改进iPhone GPS的性能，特别是在速度方面。由于位置更新滞后于设备的实时位置约3-5秒，因此位置管理器报告的速度也远远滞后于实时值。就我而言，这实在太长了。我知道我可能无能为力，但有人成功地提高了iPhone GPS的响应能力吗？每一点点都会带来不同

编辑1：

正如苹果公司推荐的那样，我的位置管理器在一个单例类中

在SingletonDataController.m中：

static CLLocationManager* locationManager;
locationManager = [CLLocationManager new];
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.headingFilter = kCLHeadingFilterNone;

if(([[UIDevice currentDevice] batteryState] == UIDeviceBatteryStateCharging) || ([[UIDevice currentDevice] batteryState] == UIDeviceBatteryStateFull)) {
    locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
} else {
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;
}

[sharedSingleton setLocationManager:locationManager];
[locationManager release];

在MapView.m内部（实际使用位置管理器的位置）：

数据处理发生在

locationManager:didUpdateToLocation:fromLocation:

内部。我不认为这里的低效率是造成滞后的原因

locationManager:didUpdateToLocation:fromLocation:

调用此方法来更新UI:

- (void)setLabels:(CLLocation*)newLocation fromOldLocation:(CLLocation*)oldLocation {
    //set speed label
    if(iterations > 0) {
        if(currentSpeed > keyStopSpeedFilter) {
            if(isFollowing) {
                [mapViewGlobal setRegion:MKCoordinateRegionMake([newLocation coordinate], mapViewGlobal.region.span)];
            }

            NSString* currentSpeedString;
            if(isCustomary) {
                currentSpeedString = [[NSString alloc] initWithFormat:@"%.1f miles per hour", (currentSpeed * 2.23693629f)];
            } else {
                currentSpeedString = [[NSString alloc] initWithFormat:@"%.1f km per hour", (currentSpeed * 3.6f)];
            }

            [speedLabel setText:currentSpeedString];
            [currentSpeedString release];
        } else {
            speedLabel.text = @"Not moving";
        }
    }

    //set average speed label
    if(iterations > 4 && movementIterations > 2) {
        NSString* averageSpeedString;
        if(isCustomary) {
            averageSpeedString = [[NSString alloc] initWithFormat:@"%.1f miles per hour", (float)((speedAverages / (long double)movementIterations) * 2.23693629f)];
        } else {
            averageSpeedString = [[NSString alloc] initWithFormat:@"%.1f km per hour", (float)((speedAverages / (long double)movementIterations) * 3.6f)];
        }
        [averageSpeedLabel setText:averageSpeedString];
        [averageSpeedString release];
    }

    //set elapsed time label
    NSInteger seconds = [[NSDate date] timeIntervalSinceDate:dataObject.locationManagerStartDate];
    NSInteger minutes = seconds / 60;
    NSInteger hours = minutes / 60;

    //get remainder
    seconds %= 60;

    NSString* timeString;
    NSString* secondsString;
    NSString* minutesString;
    NSString* hoursString;

    if((seconds % 60) < 10) {
        secondsString = [[NSString alloc] initWithFormat:@"0%i", seconds];
    } else {
        secondsString = [[NSString alloc] initWithFormat:@"%i", seconds];
    }

    if((minutes % 60) < 10) {
        minutesString = [[NSString alloc] initWithFormat:@"0%i", minutes];
    } else {
        minutesString = [[NSString alloc] initWithFormat:@"%i", minutes];
    }

    if((hours % 60) < 10) {
        hoursString = [[NSString alloc] initWithFormat:@"0%i", hours];
    } else {
        hoursString = [[NSString alloc] initWithFormat:@"%i", hours];
    }

    timeString = [[NSString alloc] initWithFormat:@"%@:%@:%@", hoursString, minutesString, secondsString];

    [elapsedTimeLabel setText:timeString];

    [timeString release], timeString = nil;
    [secondsString release], secondsString = nil;
    [minutesString release], minutesString = nil;
    [hoursString release], hoursString = nil;

    NSString* totalDistanceString;
    if(isCustomary) {
        totalDistanceString = [[NSString alloc] initWithFormat:@"Total: %.2f mi", (float)distance * 0.000621371192f];
    } else {
        totalDistanceString = [[NSString alloc] initWithFormat:@"Total: %.2f km", (float)distance / 1000.0f];
    }
    [customTopBar setTitle:totalDistanceString];
    [totalDistanceString release];
}

-（void）setLabels:（CLLocation*）newLocation fromOldLocation:（CLLocation*）oldLocation{
//设置速度标签
如果（迭代次数>0）{
如果（currentSpeed>KeysppeedFilter）{
如果（如下所示）{
[mapViewGlobal setRegion:mkCoordinatereRegionMake（[newLocation coordinate]，mapViewGlobal.region.span）]；
}
NSString*currentSpeedString；
如果（是定制的）{
currentSpeedString=[[NSString alloc]initWithFormat:@“%.1f英里/小时”（currentSpeed*2.23693629f）]；
}否则{
currentSpeedString=[[NSString alloc]initWithFormat:@“%.1f公里/小时”（currentSpeed*3.6f）]；
}
[speedLabel setText:currentSpeedString]；
[当前速度字符串释放]；
}否则{
speedLabel.text=@“未移动”；
}
}
//设置平均速度标签
如果（迭代次数>4&&movementIterations>2）{
NSString*平均速度字符串；
如果（是定制的）{
averageSpeedString=[[NSString alloc]initWithFormat:@“%.1f英里/小时”，（浮动）（（速度平均值/（长双精度）移动迭代）*2.23693629f）]；
}否则{
averageSpeedString=[[NSString alloc]initWithFormat:@“%.1f公里/小时”，（浮动）（（速度平均值/（长双）移动迭代）*3.6f）]；
}
[averageSpeedLabel setText:averageSpeedString]；
[平均速度字符串释放]；
}
//设置运行时间标签
NSInteger seconds=[[NSDate date]timeIntervalSinceDate:dataObject.locationManagerStartDate]；
NSInteger分=秒/60；
NSInteger小时=分钟/60；
//得到余数
秒%=60；
NSString*时间字符串；
NSString*第二个字符串；
NSString*分钟字符串；
NSString*小时字符串；
如果（（秒%60）<10）{
secondsString=[[NSString alloc]initWithFormat:@“0%i”，秒]；
}否则{
secondsString=[[NSString alloc]initWithFormat:@“%i”，秒]；
}
如果（（分钟%60）<10）{
MinuteString=[[NSString alloc]initWithFormat:@“0%i”，分钟]；
}否则{
MinuteString=[[NSString alloc]initWithFormat:@“%i”，分钟]；
}
如果（（小时数%60）<10）{
hoursString=[[NSString alloc]initWithFormat:@“0%i”，小时]；
}否则{
hoursString=[[NSString alloc]initWithFormat:@“%i”，小时]；
}
timeString=[[NSString alloc]initWithFormat:@“%@:%@:%@”，小时字符串，分钟字符串，秒字符串]；
[elapsedTimeLabel setText:timeString]；
[timeString release]，timeString=nil；
[secondsString释放]，secondsString=nil；
[分钟字符串释放]，分钟字符串=零；
[hoursString释放]，hoursString=nil；
NSString*总距离；
如果（是定制的）{
TotalDistancesting=[[NSString alloc]initWithFormat:@“总计：%.2f mi”，（浮点）距离*0.000621371192f]；
}否则{
TotalDistancesting=[[NSString alloc]initWithFormat:@“总计：%.2f公里，（浮动）距离/1000.0f]；
}
[customTopBar设置标题：TotalDistancesting]；
[总释放量]；
}

---

通过几个NSDate和NSLogs，我发现在我的iPhone 4上执行整个

locationManager:didUpdateToLocation:fromLocation:

（不仅仅是标签更新方法）的时间不会超过8毫秒；换句话说，数据处理不是问题。

好的，有几件事可以改善滞后。首先，始终使用KCllocationAccuracybest进行导航。这与kCLLocationAccuracyBest之间没有实际的电池使用差异，它们都以最高速度使用GPS。主要区别在于苹果的后处理

其次，不需要过滤速度==0。苹果已经做了这种过滤：如果你的GPS速度低于某个阈值（约4公里/小时），操作系统会假设你站着不动，并用相同的位置值替换所有后续样本。它会一直这样做，直到它认为你再次移动。我想他们这样做是为了避免你站着不动时在地图上“抖动”。事实上，对于“静止”值序列的最后一个实数值，速度已经下降到0，因此，如果过滤速度==0，则会丢失一个真实的GPS样本

不幸的是，他们无法避免这种过滤并获得真正的GPS样本。我和苹果谈过这件事，他们的反应是他们不会改变这种行为。kCLLocationAccuracyBestForNavigation的过滤不如kCLLocationAccuracyBest，所以最好使用它

第三，您可能已经在这样做了，但请确保在vi上调用“setNeedsDisplay”

- (void)setLabels:(CLLocation*)newLocation fromOldLocation:(CLLocation*)oldLocation {
    //set speed label
    if(iterations > 0) {
        if(currentSpeed > keyStopSpeedFilter) {
            if(isFollowing) {
                [mapViewGlobal setRegion:MKCoordinateRegionMake([newLocation coordinate], mapViewGlobal.region.span)];
            }

            NSString* currentSpeedString;
            if(isCustomary) {
                currentSpeedString = [[NSString alloc] initWithFormat:@"%.1f miles per hour", (currentSpeed * 2.23693629f)];
            } else {
                currentSpeedString = [[NSString alloc] initWithFormat:@"%.1f km per hour", (currentSpeed * 3.6f)];
            }

            [speedLabel setText:currentSpeedString];
            [currentSpeedString release];
        } else {
            speedLabel.text = @"Not moving";
        }
    }

    //set average speed label
    if(iterations > 4 && movementIterations > 2) {
        NSString* averageSpeedString;
        if(isCustomary) {
            averageSpeedString = [[NSString alloc] initWithFormat:@"%.1f miles per hour", (float)((speedAverages / (long double)movementIterations) * 2.23693629f)];
        } else {
            averageSpeedString = [[NSString alloc] initWithFormat:@"%.1f km per hour", (float)((speedAverages / (long double)movementIterations) * 3.6f)];
        }
        [averageSpeedLabel setText:averageSpeedString];
        [averageSpeedString release];
    }

    //set elapsed time label
    NSInteger seconds = [[NSDate date] timeIntervalSinceDate:dataObject.locationManagerStartDate];
    NSInteger minutes = seconds / 60;
    NSInteger hours = minutes / 60;

    //get remainder
    seconds %= 60;

    NSString* timeString;
    NSString* secondsString;
    NSString* minutesString;
    NSString* hoursString;

    if((seconds % 60) < 10) {
        secondsString = [[NSString alloc] initWithFormat:@"0%i", seconds];
    } else {
        secondsString = [[NSString alloc] initWithFormat:@"%i", seconds];
    }

    if((minutes % 60) < 10) {
        minutesString = [[NSString alloc] initWithFormat:@"0%i", minutes];
    } else {
        minutesString = [[NSString alloc] initWithFormat:@"%i", minutes];
    }

    if((hours % 60) < 10) {
        hoursString = [[NSString alloc] initWithFormat:@"0%i", hours];
    } else {
        hoursString = [[NSString alloc] initWithFormat:@"%i", hours];
    }

    timeString = [[NSString alloc] initWithFormat:@"%@:%@:%@", hoursString, minutesString, secondsString];

    [elapsedTimeLabel setText:timeString];

    [timeString release], timeString = nil;
    [secondsString release], secondsString = nil;
    [minutesString release], minutesString = nil;
    [hoursString release], hoursString = nil;

    NSString* totalDistanceString;
    if(isCustomary) {
        totalDistanceString = [[NSString alloc] initWithFormat:@"Total: %.2f mi", (float)distance * 0.000621371192f];
    } else {
        totalDistanceString = [[NSString alloc] initWithFormat:@"Total: %.2f km", (float)distance / 1000.0f];
    }
    [customTopBar setTitle:totalDistanceString];
    [totalDistanceString release];
}

kCLLocationAccuracyBestForNavigation
kCLLocationAccuracyBest
kCLLocationAccuracyNearestTenMeters
kCLLocationAccuracyHundredMeters
kCLLocationAccuracyKilometer
kCLLocationAccuracyThreeKilometers

Note: If you try with different accuracy and different distance filter value then you will be more clear about it how accurate data iPhone GPS hardware return.