AP_GPS: added ExternalAHRS backend

libraries/AP_GPS/AP_GPS.cpp

@@ -36,6 +36,7 @@
 #include "AP_GPS_UBLOX.h"
 #include "AP_GPS_MAV.h"
 #include "AP_GPS_MSP.h"
+#include "AP_GPS_ExternalAHRS.h"
 #include "GPS_Backend.h"
 
 #if HAL_ENABLE_LIBUAVCAN_DRIVERS
@@ -80,7 +81,7 @@ const AP_Param::GroupInfo AP_GPS::var_info[] = {
     // @Param: TYPE
     // @DisplayName: GPS type
     // @Description: GPS type
-    // @Values: 0:None,1:AUTO,2:uBlox,3:MTK,4:MTK19,5:NMEA,6:SiRF,7:HIL,8:SwiftNav,9:UAVCAN,10:SBF,11:GSOF,13:ERB,14:MAV,15:NOVA,16:HemisphereNMEA,17:uBlox-MovingBaseline-Base,18:uBlox-MovingBaseline-Rover,19:MSP,20:AllyStar
+    // @Values: 0:None,1:AUTO,2:uBlox,3:MTK,4:MTK19,5:NMEA,6:SiRF,7:HIL,8:SwiftNav,9:UAVCAN,10:SBF,11:GSOF,13:ERB,14:MAV,15:NOVA,16:HemisphereNMEA,17:uBlox-MovingBaseline-Base,18:uBlox-MovingBaseline-Rover,19:MSP,20:AllyStar,21:ExternalAHRS
     // @RebootRequired: True
     // @User: Advanced
     AP_GROUPINFO("TYPE",    0, AP_GPS, _type[0], HAL_GPS_TYPE_DEFAULT),
@@ -89,7 +90,7 @@ const AP_Param::GroupInfo AP_GPS::var_info[] = {
     // @Param: TYPE2
     // @DisplayName: 2nd GPS type
     // @Description: GPS type of 2nd GPS
-    // @Values: 0:None,1:AUTO,2:uBlox,3:MTK,4:MTK19,5:NMEA,6:SiRF,7:HIL,8:SwiftNav,9:UAVCAN,10:SBF,11:GSOF,13:ERB,14:MAV,15:NOVA,16:HemisphereNMEA,17:uBlox-MovingBaseline-Base,18:uBlox-MovingBaseline-Rover,19:MSP,20:AllyStar
+    // @Values: 0:None,1:AUTO,2:uBlox,3:MTK,4:MTK19,5:NMEA,6:SiRF,7:HIL,8:SwiftNav,9:UAVCAN,10:SBF,11:GSOF,13:ERB,14:MAV,15:NOVA,16:HemisphereNMEA,17:uBlox-MovingBaseline-Base,18:uBlox-MovingBaseline-Rover,19:MSP,20:AllyStar,21:ExternalAHRS
     // @RebootRequired: True
     // @User: Advanced
     AP_GROUPINFO("TYPE2",   1, AP_GPS, _type[1], 0),
@@ -376,6 +377,7 @@ bool AP_GPS::needs_uart(GPS_Type type) const
     case GPS_TYPE_UAVCAN:
     case GPS_TYPE_MAV:
     case GPS_TYPE_MSP:
+    case GPS_TYPE_EXTERNAL_AHRS:
         return false;
     default:
         break;
@@ -556,6 +558,12 @@ void AP_GPS::detect_instance(uint8_t instance)
         dstate->auto_detected_baud = false; // specified, not detected
         new_gps = new AP_GPS_MSP(*this, state[instance], nullptr);
         goto found_gps;
+#endif
+#if HAL_EXTERNAL_AHRS_ENABLED
+    case GPS_TYPE_EXTERNAL_AHRS:
+        dstate->auto_detected_baud = false; // specified, not detected
+        new_gps = new AP_GPS_ExternalAHRS(*this, state[instance], nullptr);
+        goto found_gps;
 #endif
     default:
         break;
@@ -1086,6 +1094,17 @@ void AP_GPS::handle_msp(const MSP::msp_gps_data_message_t &pkt)
 }
 #endif // HAL_MSP_GPS_ENABLED
 
+#if HAL_EXTERNAL_AHRS_ENABLED
+void AP_GPS::handle_external(const AP_ExternalAHRS::gps_data_message_t &pkt)
+{
+    for (uint8_t i=0; i<num_instances; i++) {
+        if (drivers[i] != nullptr && _type[i] == GPS_TYPE_EXTERNAL_AHRS) {
+            drivers[i]->handle_external(pkt);
+        }
+    }
+}
+#endif // HAL_EXTERNAL_AHRS_ENABLED
+
 /*
   set HIL (hardware in the loop) status for a GPS instance
  */

libraries/AP_GPS/AP_GPS.h

@@ -22,6 +22,7 @@
 #include "GPS_detect_state.h"
 #include <AP_SerialManager/AP_SerialManager.h>
 #include <AP_MSP/msp.h>
+#include <AP_ExternalAHRS/AP_ExternalAHRS.h>
 
 /**
    maximum number of GPS instances available on this platform. If more
@@ -65,6 +66,7 @@ class AP_GPS
     friend class AP_GPS_GSOF;
     friend class AP_GPS_MAV;
     friend class AP_GPS_MSP;
+    friend class AP_GPS_ExternalAHRS;
     friend class AP_GPS_MTK;
     friend class AP_GPS_MTK19;
     friend class AP_GPS_NMEA;
@@ -115,6 +117,7 @@ public:
         GPS_TYPE_UBLOX_RTK_ROVER = 18,
         GPS_TYPE_MSP = 19,
         GPS_TYPE_ALLYSTAR = 20, // AllyStar NMEA
+        GPS_TYPE_EXTERNAL_AHRS = 21,
     };
 
     /// GPS status codes
@@ -213,6 +216,9 @@ public:
 #if HAL_MSP_GPS_ENABLED
     void handle_msp(const MSP::msp_gps_data_message_t &pkt);
 #endif
+#if HAL_EXTERNAL_AHRS_ENABLED
+    void handle_external(const AP_ExternalAHRS::gps_data_message_t &pkt);
+#endif
 
     // Accessor functions
 

libraries/AP_GPS/AP_GPS_ExternalAHRS.cpp

@@ -0,0 +1,98 @@
+/*
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+//
+//  ExternalAHRS GPS driver
+//
+#include <AP_ExternalAHRS/AP_ExternalAHRS.h>
+#include "AP_GPS_ExternalAHRS.h"
+
+#if HAL_EXTERNAL_AHRS_ENABLED
+
+AP_GPS_ExternalAHRS::AP_GPS_ExternalAHRS(AP_GPS &_gps, AP_GPS::GPS_State &_state, AP_HAL::UARTDriver *_port) :
+    AP_GPS_Backend(_gps, _state, _port)
+{
+}
+
+// Reading does nothing in this class; we simply return whether or not
+// the latest reading has been consumed.  By calling this function we assume
+// the caller is consuming the new data;
+bool AP_GPS_ExternalAHRS::read(void)
+{
+    if (new_data) {
+        new_data = false;
+        return true;
+    }
+    return false;
+}
+
+// handles an incoming ExternalAHRS message and sets
+// corresponding gps data appropriately;
+void AP_GPS_ExternalAHRS::handle_external(const AP_ExternalAHRS::gps_data_message_t &pkt)
+{
+    check_new_itow(pkt.ms_tow, sizeof(pkt));
+
+    state.time_week = pkt.gps_week;
+    state.time_week_ms = pkt.ms_tow;
+    if (pkt.fix_type == 0) {
+        state.status = AP_GPS::NO_FIX;
+    } else {
+        state.status = (AP_GPS::GPS_Status)pkt.fix_type;
+    }
+    state.num_sats = pkt.satellites_in_view;
+
+    Location loc = {};
+    loc.lat = pkt.latitude;
+    loc.lng = pkt.longitude;
+    loc.alt = pkt.msl_altitude;
+
+    state.location = loc;
+    state.hdop = pkt.hdop;
+    state.vdop = pkt.vdop;
+
+    state.have_vertical_velocity = true;
+    state.velocity.x = pkt.ned_vel_north;
+    state.velocity.y = pkt.ned_vel_east;
+    state.velocity.z = pkt.ned_vel_down;
+
+    state.ground_course = wrap_360(degrees(atan2f(state.velocity.y, state.velocity.x)));
+    state.ground_speed = norm(state.velocity.y, state.velocity.x);
+
+    state.have_speed_accuracy = true;
+    state.have_horizontal_accuracy = true;
+    state.have_vertical_accuracy = true;
+    state.have_vertical_velocity = true;
+
+    state.horizontal_accuracy = pkt.horizontal_pos_accuracy;
+    state.vertical_accuracy = pkt.vertical_pos_accuracy;
+    state.speed_accuracy = pkt.horizontal_vel_accuracy;
+
+    state.last_gps_time_ms = AP_HAL::millis();
+
+    new_data = true;
+}
+
+/*
+  return velocity lag in seconds
+ */
+bool AP_GPS_ExternalAHRS::get_lag(float &lag_sec) const
+{
+    // fixed assumed lag
+    lag_sec = 0.11;
+    return true;
+}
+
+#endif // HAL_EXTERNAL_AHRS_ENABLED
+

libraries/AP_GPS/AP_GPS_ExternalAHRS.h

@@ -0,0 +1,46 @@
+/*
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+//
+//  ExternalAHRS GPS driver which accepts gps position data from an external AHRS unit
+//
+#pragma once
+
+#include <AP_Common/AP_Common.h>
+#include <AP_HAL/AP_HAL.h>
+
+#include "AP_GPS.h"
+#include "GPS_Backend.h"
+
+#if HAL_EXTERNAL_AHRS_ENABLED
+
+class AP_GPS_ExternalAHRS : public AP_GPS_Backend
+{
+public:
+    AP_GPS_ExternalAHRS(AP_GPS &_gps, AP_GPS::GPS_State &_state, AP_HAL::UARTDriver *_port);
+
+    bool read() override;
+    void handle_external(const AP_ExternalAHRS::gps_data_message_t &pkt) override;
+
+    const char *name() const override { return "ExternalAHRS"; }
+
+    bool get_lag(float &lag_sec) const override;
+
+private:
+    bool new_data;
+};
+
+#endif // HAL_EXTERNAL_AHRS_ENABLED
+

libraries/AP_GPS/GPS_Backend.h

@@ -54,7 +54,10 @@ public:
 #if HAL_MSP_GPS_ENABLED
     virtual void handle_msp(const MSP::msp_gps_data_message_t &pkt) { return; }
 #endif
-
+#if HAL_EXTERNAL_AHRS_ENABLED
+    virtual void handle_external(const AP_ExternalAHRS::gps_data_message_t &pkt) { return; }
+#endif
+    
     // driver specific lag, returns true if the driver is confident in the provided lag
     virtual bool get_lag(float &lag) const { lag = 0.2f; return true; }