硬件架构图

可以看到左下角的“GNSS定位模块”其实是有IMU和GPS Antenna 组成的。

执行分析

代码

class GpsMonitor : public RecurrentRunner {public:GpsMonitor();void RunOnce(const double current_time) override;
};void GpsMonitor::RunOnce(const double current_time) {auto manager = MonitorManager::Instance();Component* component = apollo::common::util::FindOrNull(*manager->GetStatus()->mutable_components(), FLAGS_gps_component_name);if (component == nullptr) {// GPS is not monitored in current mode, skip.return;}ComponentStatus* component_status = component->mutable_other_status();component_status->clear_status();static auto gnss_best_pose_reader =manager->CreateReader(FLAGS_gnss_best_pose_topic);gnss_best_pose_reader->Observe();const auto gnss_best_pose_status = gnss_best_pose_reader->GetLatestObserved();if (gnss_best_pose_status == nullptr) {SummaryMonitor::EscalateStatus(ComponentStatus::ERROR,"No GnssBestPose message", component_status);return;}switch (gnss_best_pose_status->sol_type()) {case SolutionType::NARROW_INT:SummaryMonitor::EscalateStatus(ComponentStatus::OK, "", component_status);break;case SolutionType::SINGLE:SummaryMonitor::EscalateStatus(ComponentStatus::WARN, "SolutionType is SINGLE", component_status);break;default:SummaryMonitor::EscalateStatus(ComponentStatus::ERROR,"SolutionType is wrong", component_status);break;}
}

分析

gps monitor 核心内容就70 line code

基本思路如下：

1. 从配置文件中查找GPS是否是被配置的监控组件
2. 如果是的话，订阅GnssBestPose topic，并收取数据
3. 获取最新的数据，如果最新的数据为null，发出ERROR级别的故障
4. 如果获取的数据类型为NARROW_INT，表示正常
5. 如果获取的数据类型为SINGLE，表示WARN
   1. 这里根据apollo 的定位算法设计与硬件架构，不难猜SINGLE 代表IMU 惯性单元或GPS有一个没有正常输出数据
   2. 如果获取的数据类型为其他情况，表示ERROR

GnssBestPose 和 SolutionType 的定义都来自 GNSS 驱动。

modules/drivers/gnss/proto/gnss_best_pose.proto

enum SolutionType {NONE = 0;FIXEDPOS = 1;FIXEDHEIGHT = 2;FLOATCONV = 4;WIDELANE = 5;NARROWLANE = 6;DOPPLER_VELOCITY = 8;SINGLE = 16;PSRDIFF = 17;WAAS = 18;PROPOGATED = 19;OMNISTAR = 20;L1_FLOAT = 32;IONOFREE_FLOAT = 33;NARROW_FLOAT = 34;L1_INT = 48;WIDE_INT = 49;NARROW_INT = 50;RTK_DIRECT_INS =51;  // RTK filter is directly initialized from the INS filter.INS_SBAS = 52;INS_PSRSP = 53;INS_PSRDIFF = 54;INS_RTKFLOAT = 55;INS_RTKFIXED = 56;INS_OMNISTAR = 57;INS_OMNISTAR_HP = 58;INS_OMNISTAR_XP = 59;OMNISTAR_HP = 64;OMNISTAR_XP = 65;PPP_CONVERGING = 68;PPP = 69;INS_PPP_CONVERGING = 73;INS_PPP = 74;
}