feat(pps): preserve loop dynamics across nav periods

soc/software/gps_system/tests/test_gps_pps_quality.c

@@ -107,6 +107,69 @@ static void test_profile_parameters_are_ordered(void)
 	assert(robust.lock_release_ticks >= precision.lock_release_ticks);
 }
 
+static void test_period_scaled_hysteresis_and_settling(void)
+{
+	gps_pps_quality_selector_t selector;
+	gps_pps_quality_selector_init_period(&selector, 0.5);
+	assert(selector.upgrade_updates == 4u);
+	assert(selector.degrade_updates == 2u);
+	gps_pps_loop_profile_t precision =
+		gps_pps_loop_profile_for_period(GPS_PPS_PROFILE_PRECISION, 0.5);
+	gps_pps_loop_profile_t robust =
+		gps_pps_loop_profile_for_period(GPS_PPS_PROFILE_ROBUST, 0.5);
+	assert(precision.lock_acquire_updates == 2u);
+	assert(precision.software_settle_updates == 5u);
+	assert(robust.lock_acquire_updates == 4u);
+	assert(robust.software_settle_updates == 7u);
+
+	gps_pps_quality_selector_init_period(&selector, 1.0);
+	assert(selector.upgrade_updates == 2u);
+	assert(selector.degrade_updates == 2u);
+	precision = gps_pps_loop_profile_for_period(
+		GPS_PPS_PROFILE_PRECISION, 1.0);
+	robust = gps_pps_loop_profile_for_period(
+		GPS_PPS_PROFILE_ROBUST, 1.0);
+	assert(precision.lock_acquire_updates == 2u);
+	assert(precision.software_settle_updates == 3u);
+	assert(robust.lock_acquire_updates == 2u);
+	assert(robust.software_settle_updates == 4u);
+}
+
+static void assert_coefficients(
+	gps_pps_profile_t profile,
+	double period_sec,
+	int64_t expected_kp,
+	int64_t expected_ki)
+{
+	int64_t kp = 0;
+	int64_t ki = 0;
+	uint32_t max_slew = 0u;
+	gps_pps_loop_profile_t parameters =
+		gps_pps_loop_profile_for_period(profile, period_sec);
+	assert(gps_pps_loop_coefficients(
+		parameters, period_sec, 125000000.0,
+		&kp, &ki, &max_slew));
+	assert(kp == expected_kp);
+	assert(ki == expected_ki);
+	assert(max_slew == 85899u);
+}
+
+static void test_period_scaled_discrete_coefficients(void)
+{
+	/* The production 200 ms coefficients remain bit-for-bit unchanged. */
+	assert_coefficients(GPS_PPS_PROFILE_ACQUIRE, 0.2, 764018, 64006);
+	assert_coefficients(GPS_PPS_PROFILE_PRECISION, 0.2, 222838, 5445);
+	assert_coefficients(GPS_PPS_PROFILE_ROBUST, 0.2, 84891, 640);
+
+	/* Other cadences exponentiate those proven discrete poles in time. */
+	assert_coefficients(GPS_PPS_PROFILE_ACQUIRE, 0.5, 615780, 127492);
+	assert_coefficients(GPS_PPS_PROFILE_PRECISION, 0.5, 209783, 12804);
+	assert_coefficients(GPS_PPS_PROFILE_ROBUST, 0.5, 82980, 1564);
+	assert_coefficients(GPS_PPS_PROFILE_ACQUIRE, 1.0, 447388, 178038);
+	assert_coefficients(GPS_PPS_PROFILE_PRECISION, 1.0, 190239, 23149);
+	assert_coefficients(GPS_PPS_PROFILE_ROBUST, 1.0, 79923, 3011);
+}
+
 static void test_quality_boundaries_and_recovery(void)
 {
 	gps_pps_quality_selector_t selector;
@@ -167,6 +230,8 @@ int main(void)
 	test_hysteretic_profile_transitions();
 	test_alternating_quality_does_not_upgrade();
 	test_profile_parameters_are_ordered();
+	test_period_scaled_hysteresis_and_settling();
+	test_period_scaled_discrete_coefficients();
 	test_quality_boundaries_and_recovery();
 	puts("gps_pps_quality tests passed");
 	return 0;