Add PPS capture message to logged topics, simplify timestamp logic and small cleanup

src/drivers/camera_capture/camera_capture.cpp

@@ -193,10 +193,8 @@ CameraCapture::publish_trigger()
 
 
 	if (_pps_hrt_timestamp > 0) {
-		// Current RTC time (RTC time captured by the PPS module + elapsed time since capture)
-		uint64_t gps_utc_time = _pps_rtc_timestamp + hrt_elapsed_time(&_pps_hrt_timestamp);
-		// Current RTC time - elapsed time since capture interrupt event
-		trigger.timestamp_utc = gps_utc_time - hrt_elapsed_time(&trigger.timestamp);
+		// Last PPS RTC time + elapsed time to the camera capture interrupt
+		trigger.timestamp_utc = _pps_rtc_timestamp + (trigger.timestamp - _pps_hrt_timestamp);
 
 	} else {
 		// No PPS capture received, use RTC clock as fallback

src/drivers/camera_capture/camera_capture.hpp

@@ -132,8 +132,8 @@ private:
 	hrt_abstime		_last_trig_time{0};
 	uint32_t 		_capture_overflows{0};
 
-	uint64_t    _pps_hrt_timestamp{0};
-	uint64_t    _pps_rtc_timestamp{0};
+	hrt_abstime	_pps_hrt_timestamp{0};
+	uint64_t		_pps_rtc_timestamp{0};
 
 	// Signal capture callback
 	void			capture_callback(uint32_t chan_index, hrt_abstime edge_time, uint32_t edge_state, uint32_t overflow);

src/drivers/camera_trigger/camera_trigger.cpp

@@ -174,8 +174,8 @@ private:
 	bool 			_turning_on{false};
 	matrix::Vector2f	_last_shoot_position{0.f, 0.f};
 	bool			_valid_position{false};
-	uint64_t    _pps_hrt_timestamp{0};
-	uint64_t    _pps_rtc_timestamp{0};
+	hrt_abstime	_pps_hrt_timestamp{0};
+	uint64_t		_pps_rtc_timestamp{0};
 
 	//Camera Auto Mount Pivoting Oblique Survey (CAMPOS)
 	uint32_t		_CAMPOS_num_poses{0};

src/drivers/pps_capture/PPSCapture.cpp

@@ -99,14 +99,12 @@ void PPSCapture::Run()
 	pps_capture_s pps_capture;
 	pps_capture.timestamp = _hrt_timestamp;
 	// GPS UTC time when the GPIO interrupt was triggered
-	// UTC time + elapsed time since the UTC time was received - eleapsed time since the PPS interrupt
-	// event
-	uint64_t gps_utc_time = _last_gps_utc_timestamp + hrt_elapsed_time(&_last_gps_timestamp)
-				- hrt_elapsed_time(&_hrt_timestamp);
+	// Last UTC time received from the GPS + elapsed time to the PPS interrupt
+	uint64_t gps_utc_time = _last_gps_utc_timestamp + (_hrt_timestamp - _last_gps_timestamp);
 
 	// (For ubx F9P) The rising edge of the PPS pulse is aligned to the top of second GPS time base.
 	// So, remove the fraction of second and shift to the next second. The interrupt is triggered
-	// before the matching timestamp tranfered, which means the last received GPS time is always
+	// before the matching timestamp is received via a UART message, which means the last received GPS time is always
 	// behind.
 	pps_capture.rtc_timestamp = gps_utc_time - (gps_utc_time % USEC_PER_SEC) + USEC_PER_SEC;
 

src/drivers/pps_capture/PPSCapture.hpp

@@ -73,12 +73,9 @@ private:
 	uORB::Publication<pps_capture_s>	_pps_capture_pub{ORB_ID(pps_capture)};
 	uORB::Subscription								_sensor_gps_sub{ORB_ID(sensor_gps)};
 
-	static constexpr unsigned USEC_IN_1_SEC{1000000}; // microseconds in 1 second
-	static constexpr unsigned MAX_POSITIVE_DRIFT{USEC_IN_1_SEC / 2}; // microseconds
-
 	hrt_abstime _hrt_timestamp{0};
 
-	uint64_t _last_gps_timestamp{0};
-	uint64_t _last_gps_utc_timestamp{0};
+	hrt_abstime	_last_gps_timestamp{0};
+	uint64_t		_last_gps_utc_timestamp{0};
 
 };

src/modules/logger/logged_topics.cpp

@@ -172,6 +172,7 @@ void LoggedTopics::add_default_topics()
 	add_optional_topic_multi("sensor_accel", 1000, 4);
 	add_optional_topic_multi("sensor_baro", 1000, 4);
 	add_topic_multi("sensor_gps", 1000, 2);
+	add_topic("pps_capture", 1000);
 	add_optional_topic_multi("sensor_gyro", 1000, 4);
 	add_optional_topic_multi("sensor_mag", 1000, 4);
 	add_topic_multi("vehicle_imu", 500, 4);