commander: Changes resulting from code review

Change units of parameters from uSec to sec.
Change recommended FW value for COM_POS_FS_GAIN from 2 to 0
Fix error in parameter description for COM_POS_FS_PROB
Fix error in unit for COM_POS_FS_GAIN

src/modules/commander/commander.cpp

@@ -146,7 +146,7 @@ static constexpr uint8_t COMMANDER_MAX_GPS_NOISE = 60;		/**< Maximum percentage
 
 #define STICK_ON_OFF_LIMIT 0.9f
 
-#define POSITION_TIMEOUT		(1 * 1000 * 1000)	/**< consider the local or global position estimate invalid after 1000ms */
+#define POSITION_TIMEOUT		1			/**< default number of seconds of position health check failure required to declare the position invalid */
 #define FAILSAFE_DEFAULT_TIMEOUT	(3 * 1000 * 1000)	/**< hysteresis time - the failsafe will trigger after 3 seconds in this state */
 #define OFFBOARD_TIMEOUT		500000
 #define DIFFPRESS_TIMEOUT		2000000
@@ -159,14 +159,14 @@ static constexpr uint8_t COMMANDER_MAX_GPS_NOISE = 60;		/**< Maximum percentage
 #define INAIR_RESTART_HOLDOFF_INTERVAL	500000
 
 /* Controls the probation period which is the amount of time required for position and velocity checks to pass before the validity can be changed from false to true*/
-#define POSVEL_PROBATION_TAKEOFF 30E6		/**< probation duration set at takeoff (usec) */
+#define POSVEL_PROBATION_TAKEOFF 30		/**< probation duration set at takeoff (sec) */
 #define POSVEL_PROBATION_MIN 1E6		/**< minimum probation duration (usec) */
 #define POSVEL_PROBATION_MAX 100E6		/**< maximum probation duration (usec) */
 #define POSVEL_VALID_PROBATION_FACTOR 10	/**< the rate at which the probation duration is increased while checks are failing */
 
 /* Parameters controlling the sensitivity of the position failsafe */
-static int32_t posctl_nav_loss_delay = POSITION_TIMEOUT;
-static int32_t posctl_nav_loss_prob = POSVEL_PROBATION_TAKEOFF;
+static int32_t posctl_nav_loss_delay = POSITION_TIMEOUT * (1000 * 1000);
+static int32_t posctl_nav_loss_prob = POSVEL_PROBATION_TAKEOFF * (1000 * 1000);
 static int32_t posctl_nav_loss_gain = POSVEL_VALID_PROBATION_FACTOR;
 
 /*
@@ -1701,8 +1701,14 @@ int commander_thread_main(int argc, char *argv[])
 
 	control_status_leds(&status, &armed, true, &battery, &cpuload);
 
+	/* Get parameter values controlloing activation of position failure failsafe and convert to required units*/
+	const int32_t sec_to_usec = (1000 * 1000);
+	int32_t init_param_val = POSITION_TIMEOUT;
 	param_get(param_find("COM_POS_FS_DELAY"), &posctl_nav_loss_delay);
+	posctl_nav_loss_delay = init_param_val * sec_to_usec; // convert to uSec
+	init_param_val = POSVEL_PROBATION_TAKEOFF;
 	param_get(param_find("COM_POS_FS_PROB"), &posctl_nav_loss_prob);
+	posctl_nav_loss_prob = init_param_val * sec_to_usec; // convert to uSec
 	param_get(param_find("COM_POS_FS_GAIN"), &posctl_nav_loss_gain);
 
 	/* now initialized */

src/modules/commander/commander_params.c

@@ -641,37 +641,36 @@ PARAM_DEFINE_INT32(COM_ARM_AUTH, 256010);
 /**
  * Loss of position failsafe activation delay.
  *
- * This sets number of uSec that the position checks need to be failed before the failsafe will activate.
- * The default value has been optimised for rotary wing applications. For fixed wing applications, a larger value between 5E6 and 10E6 should be used.
+ * This sets number of second that the position checks need to be failed before the failsafe will activate.
+ * The default value has been optimised for rotary wing applications. For fixed wing applications, a larger value between 5 and 10 should be used.
  *
- * @unit uSec
+ * @unit sec
  * @reboot_required true
  * @group Commander
  */
-PARAM_DEFINE_INT32(COM_POS_FS_DELAY, 1E6);
+PARAM_DEFINE_INT32(COM_POS_FS_DELAY, 1);
 
 /**
  * Loss of position probation delay at takeoff.
  *
- * The probation delay is number of uSec that the EKF innovation checks need to pass for the positon to be declared good once it has been declared bad.
+ * The probation delay is number of seconds that the EKF innovation checks need to pass for the positon to be declared good after it has been declared bad.
  * The probation delay will be reset to this parameter value when takeoff is detected.
- * After takeoff, if position checks are passing, the probation delay will reduce by one uSec for every lapsed uSec of valid position down to a minimum of 1E6 uSec.
- * If position checks are failing, the probation delay will increase by COM_POS_FS_FACT micro seconds for every lapsed uSec up to a maximum of 100E6 uSec.
- * The default value has been optimised for rotary wing applications. For fixed wing applications, a value of 1E6 should be used.
+ * After takeoff, if position checks are passing, the probation delay will reduce by one second for every lapsed second of valid position down to a minimum of 1 second.
+ * If position checks are failing, the probation delay will increase by COM_POS_FS_GAIN seconds for every lapsed second up to a maximum of 100 seconds.
+ * The default value has been optimised for rotary wing applications. For fixed wing applications, a value of 1 should be used.
  *
- * @unit uSec
+ * @unit sec
  * @reboot_required true
  * @group Commander
  */
-PARAM_DEFINE_INT32(COM_POS_FS_PROB, 30E6);
+PARAM_DEFINE_INT32(COM_POS_FS_PROB, 30);
 
 /**
  * Loss of position probation gain factor.
  *
  * This sets the rate that the loss of position probation time grows when position checks are failing.
- * The default value has been optimised for rotary wing applications. For fixed wing applications a value of 2 should be used.
+ * The default value has been optimised for rotary wing applications. For fixed wing applications a value of 0 should be used.
  *
- * @unit uSec
  * @reboot_required true
  * @group Commander
  */