autotest: add test for blending while affinity is running

Tools/autotest/arducopter.py

@@ -9156,6 +9156,75 @@ class AutoTestCopter(vehicle_test_suite.TestSuite):
         self.context_pop()
         self.reboot_sitl()
 
+    def GPSBlendingAffinity(self):
+        '''test blending when affinity in use'''
+        # configure:
+        self.set_parameters({
+            "WP_YAW_BEHAVIOR": 0,  # do not yaw
+            "GPS2_TYPE": 1,
+            "SIM_GPS2_TYPE": 1,
+            "SIM_GPS2_DISABLE": 0,
+            "SIM_GPS_POS_X": 1.0,
+            "SIM_GPS_POS_Y": -1.0,
+            "SIM_GPS2_POS_X": -1.0,
+            "SIM_GPS2_POS_Y": 1.0,
+            "GPS_AUTO_SWITCH": 2,
+
+            "EK3_AFFINITY" : 1,
+            "EK3_IMU_MASK": 7,
+            "SIM_IMU_COUNT": 3,
+            "INS_ACC3OFFS_X": 0.001,
+            "INS_ACC3OFFS_Y": 0.001,
+            "INS_ACC3OFFS_Z": 0.001,
+        })
+        # force-calibration of accel:
+        self.run_cmd(mavutil.mavlink.MAV_CMD_PREFLIGHT_CALIBRATION, p5=76)
+        self.reboot_sitl()
+
+        alt = 10
+        self.takeoff(alt, mode='GUIDED')
+        self.fly_guided_move_local(30, 0, alt)
+        self.fly_guided_move_local(30, 30, alt)
+        self.fly_guided_move_local(0, 30, alt)
+        self.fly_guided_move_local(0, 0, alt)
+        self.change_mode('LAND')
+
+        current_log_file = self.dfreader_for_current_onboard_log()
+
+        self.wait_disarmed()
+
+        # ensure that the blended solution is always about half-way
+        # between the two GPSs:
+        current_ts = None
+        max_errors = [0, 0, 0]
+        while True:
+            m = current_log_file.recv_match(type='XKF1')
+            if m is None:
+                break
+            if current_ts is None:
+                if m.C != 0:  # noqa
+                    continue
+                current_ts = m.TimeUS
+                measurements = {}
+            if m.TimeUS != current_ts:
+                current_ts = None
+                continue
+            measurements[m.C] = (m.PN, m.PE, m.PD)
+            if len(measurements) == 3:
+                # check lat:
+                for n in 0, 1, 2:
+                    expected_blended = 0.5*measurements[0][n] + 0.5*measurements[1][n]
+                    axis_epsilons = [0.02, 0.02, 0.03]
+                    epsilon = axis_epsilons[n]
+                    error = abs(measurements[2][n] - expected_blended)
+                    # self.progress(f"{n=} {error=}")
+                    if error > max_errors[n]:
+                        max_errors[n] = error
+                    if error > epsilon:
+                        raise NotAchievedException(f"Blended diverged {n=} {measurements[0][n]=} {measurements[1][n]=} {measurements[2][n]=} {error=}")  # noqa:E501
+                current_ts = None
+        self.progress(f"{max_errors=}")
+
     def Callisto(self):
         '''Test Callisto'''
         self.customise_SITL_commandline(
@@ -11791,6 +11860,7 @@ class AutoTestCopter(vehicle_test_suite.TestSuite):
             self.GPSBlending,
             self.GPSWeightedBlending,
             self.GPSBlendingLog,
+            self.GPSBlendingAffinity,
             self.DataFlash,
             Test(self.DataFlashErase, attempts=8),
             self.Callisto,