首先，iBeacon 的标志是下面这张图片
iBeacon
网上查资料说苹果在13年的WWDC上发布iOS7上配备的新功能。
最近，利用iBeacon设备做了下定位的算法研究，故此来总结下，也希望能和大家交流下。
下面进入正题，iBeacon这项技术是苹果建立在低功耗蓝牙的技术上做出来的东西。具体来说是利用BLE中名为"通告帧"的广播帧。通告帧是由配备BLE的设备定期发出，只要是支持BLE的终端，都可以接受到信号。通告帧的有效载荷部分，写入了苹果定义的数据。
一个iBeacon基站的数据大致由四部分信息组成：
- 1 、UUID（universally unique identifier）：一个128位的唯一标识一个或多个Beacon基站为特定类型或特定的组织。
- 2、 Major：一个16位的无符号整数，可以将具有相同proximity UUID的Beacon基站组织联系起来。（用户可以自定义)
- 3、 Minor：同上。
- 4、Measured Power ：是iBeacon发送模块与接收器之间距离为1米时的信号强度（RSSI）参照值。
通过蓝牙低功耗技术（BLE）发送特定的识别信息，来确定Beacon基站和设备之间的相对距离。而这个距离并不是精密推算的，而是将其分为三级：
- 约10厘米（immediate）
- 1米以内（near）
- 1米以外（far）
这是因为，发送和接受设备之间的距离在1米之内时，RSSI值基本是按照理论值减少的，而在1米外，收到发射波的影响，RSSI不会明显的随距离增加减少，而是会上下波动。也就是说，1米外的距离无法非常精密推测，可以用far来概括。
接下来，进入重点：
既然，用一个iBeacon我们可以测出Beacon设备和扫描Beacon设备之间的距离（Apple的API中已给出距离值）。那么，猜想下，有三个Beacon，然后知道他们的坐标信息，那么我们拿着手机去不断的扫描这三个Beacon的RSSI信息就可以利用定位算法来进行定位了。
一篇关于用iBeacon定位的文章
最后，上代码
关于开始定位的部分
UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeBadge | UIUserNotificationTypeSound | UIUserNotificationTypeAlert categories:nil];
[[UIApplication sharedApplication] registerUserNotificationSettings:settings];
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
NSArray *myBeacon = @[UUID_BEACON_O, UUID_BEACON_T, UUID_BEACON_H];
for (NSString *uuid in myBeacon) {
NSString *identifier = @"";
if ([uuid isEqualToString:UUID_BEACON_O]) {
identifier = @"左后";
}else if ([uuid isEqualToString:UUID_BEACON_T]) {
identifier = @"右后";
}else if ([uuid isEqualToString:UUID_BEACON_H]) {
identifier = @"左前";
}
CLBeaconRegion *beacon = [[CLBeaconRegion alloc] initWithProximityUUID:[[NSUUID alloc] initWithUUIDString:uuid]
identifier:identifier];
beacon.notifyOnExit = YES;
beacon.notifyOnEntry = YES;
beacon.notifyEntryStateOnDisplay = YES;
[self.locationManager startMonitoringForRegion:beacon];
[self.locationManager startRangingBeaconsInRegion:beacon];
}
[self.locationManager requestAlwaysAuthorization];
关于位置的Delegate部分
- (void)locationManager:(CLLocationManager *)manager didEnterRegion:(CLRegion *)region {
if ([region isKindOfClass:[CLBeaconRegion class]]) {
UILocalNotification *notification = [[UILocalNotification alloc] init];
notification.alertBody = [NSString stringWithFormat:@"你已进入到 %@ 范围内", region.identifier];
notification.soundName = @"Default";
[[UIApplication sharedApplication] presentLocalNotificationNow:notification];
NSLog(@"%@", [NSString stringWithFormat:@"你已进入到 %@ 范围内", region.identifier]);
}
}
- (void)locationManager:(CLLocationManager *)manager didExitRegion:(CLRegion *)region {
if ([region isKindOfClass:[CLBeaconRegion class]]) {
UILocalNotification *notification = [[UILocalNotification alloc] init];
notification.alertBody = [NSString stringWithFormat:@"你已离开 %@ 的范围", region.identifier];
notification.soundName = @"Default";
[[UIApplication sharedApplication] presentLocalNotificationNow:notification];
NSLog(@"%@", [NSString stringWithFormat:@"你已离开 %@ 的范围", region.identifier]);
}
}
- (void)locationManager:(CLLocationManager *)manager didRangeBeacons:(NSArray<CLBeacon *> *)beacons inRegion:(CLBeaconRegion *)region {
for (CLBeacon *beacon in beacons) {
// NSLog(@"beacon Info : rssi is %ld, major is %@, minor is %@, accuracy is %f, proximity is %ld.", beacon.rssi, beacon.major, beacon.minor, beacon.accuracy, beacon.proximity);
if (self.beaconDataSource.count == 3) {
if ([[beacon.proximityUUID UUIDString] isEqualToString:UUID_BEACON_O]) {
[self.beaconDataSource replaceObjectAtIndex:0 withObject:beacon];
[self.wait1 addObject:beacon]; //采集数据 左后
}
if ([[beacon.proximityUUID UUIDString]isEqualToString:UUID_BEACON_T]) {
[self.beaconDataSource replaceObjectAtIndex:1 withObject:beacon];
[self.wait2 addObject:beacon]; //采集数据 右后
}
if ([[beacon.proximityUUID UUIDString]isEqualToString:UUID_BEACON_H]) {
[self.beaconDataSource replaceObjectAtIndex:2 withObject:beacon];
[self.wait3 addObject:beacon]; //采集数据 左前
}
if (!self.testButton.selected) { //测试按钮没有选中
//实时刷新位置信息
if (self.wait1.count == 20 && self.wait2.count == 20 && self.wait3.count == 20) {
// NSArray *result = [DealModel dealWithBaseData:@[@[@"0", @"0"], @[@"220", @"0"], @[@"110", @"110"]] andThreeAuxData:@[self.wait1, self.wait2, self.wait3] andReal:@[self.textX.text, self.textY.text]];
DataProcessing *data = [[DataProcessing alloc] init];
NSArray *result2 = [data dealWithBaseData:@[@[@"0", @"0"], @[@"220", @"0"], @[@"110", @"110"]] andThreeAuxData:@[self.wait1, self.wait2, self.wait3] andReal:@[@"",@""]];
self.result1.text = self.result2.text;
self.result2.text = [NSString stringWithFormat:@"X : %@\nY : %@", result2[0], result2[1]];
NSLog(@"%@", data);
// self.xyView.center = CGPointMake([result[0] floatValue], [result[1] floatValue]);
[self.wait1 removeAllObjects];
[self.wait2 removeAllObjects];
[self.wait3 removeAllObjects];
self.sureButton.selected = NO;
self.sureButton.backgroundColor = [UIColor blackColor];
}
}else {
//开始测试单个设备误差
if (self.wait1.count == 20) {
if (![self.textX.text isEqualToString:@""])
[DataProcessing testErrorWithUUID:UUID_BEACON_O andRealValue:self.textX.text andTestArray:self.wait1];
[self.wait1 removeAllObjects];
[self.wait2 removeAllObjects];
[self.wait3 removeAllObjects];
}else if (self.wait2.count == 20) {
if (![self.textX.text isEqualToString:@""])
[DataProcessing testErrorWithUUID:UUID_BEACON_T andRealValue:self.textX.text andTestArray:self.wait2];
[self.wait1 removeAllObjects];
[self.wait2 removeAllObjects];
[self.wait3 removeAllObjects];
}else if (self.wait3.count == 20) {
if (![self.textX.text isEqualToString:@""])
[DataProcessing testErrorWithUUID:UUID_BEACON_H andRealValue:self.textX.text andTestArray:self.wait3];
[self.wait1 removeAllObjects];
[self.wait2 removeAllObjects];
[self.wait3 removeAllObjects];
}
}
[self.localView refreshWithArray:self.beaconDataSource];
}else {
if ([[beacon.proximityUUID UUIDString] isEqualToString:UUID_BEACON_O] || [[beacon.proximityUUID UUIDString]isEqualToString:UUID_BEACON_T] || [[beacon.proximityUUID UUIDString]isEqualToString:UUID_BEACON_H]) {
[self.beaconDataSource addObject:beacon];
}
}
}
[self.beaconTableView reloadData];
}
