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refclock: add maxdispersion option

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This can be used to prevent accumulation of samples with estimated
dispersion above given limit. By default, this limit is disabled.
This commit is contained in:
Miroslav Lichvar
2014-05-21 14:27:50 +02:00
parent e147f2f11e
commit b745b6d546
4 changed files with 23 additions and 4 deletions
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15
refclock.c
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@@ -57,6 +57,7 @@ struct MedianFilter {
int last;
int avg_var_n;
double avg_var;
double max_var;
struct FilterSample *samples;
int *selected;
double *x_data;
@@ -100,7 +101,7 @@ static void slew_samples(struct timeval *raw, struct timeval *cooked, double dfr
static void add_dispersion(double dispersion, void *anything);
static void log_sample(RCL_Instance instance, struct timeval *sample_time, int filtered, int pulse, double raw_offset, double cooked_offset, double dispersion);
static void filter_init(struct MedianFilter *filter, int length);
static void filter_init(struct MedianFilter *filter, int length, double max_dispersion);
static void filter_fini(struct MedianFilter *filter);
static void filter_reset(struct MedianFilter *filter);
static double filter_get_avg_sample_dispersion(struct MedianFilter *filter);
@@ -245,7 +246,7 @@ RCL_AddRefclock(RefclockParameters *params)
return 0;
}
filter_init(&inst->filter, params->filter_length);
filter_init(&inst->filter, params->filter_length, params->max_dispersion);
inst->source = SRC_CreateNewInstance(inst->ref_id, SRC_REFCLOCK, params->sel_option, NULL);
@@ -622,7 +623,7 @@ log_sample(RCL_Instance instance, struct timeval *sample_time, int filtered, int
}
static void
filter_init(struct MedianFilter *filter, int length)
filter_init(struct MedianFilter *filter, int length, double max_dispersion)
{
if (length < 1)
length = 1;
@@ -634,6 +635,7 @@ filter_init(struct MedianFilter *filter, int length)
/* set first estimate to system precision */
filter->avg_var_n = 0;
filter->avg_var = LCL_GetSysPrecisionAsQuantum() * LCL_GetSysPrecisionAsQuantum();
filter->max_var = max_dispersion * max_dispersion;
filter->samples = MallocArray(struct FilterSample, filter->length);
filter->selected = MallocArray(int, filter->length);
filter->x_data = MallocArray(double, filter->length);
@@ -861,6 +863,13 @@ filter_get_sample(struct MedianFilter *filter, struct timeval *sample_time, doub
d = sqrt(var);
}
/* drop the sample if variance is larger than allowed maximum */
if (filter->max_var > 0.0 && var > filter->max_var) {
DEBUG_LOG(LOGF_Refclock, "filter dispersion too large disp=%.9f max=%.9f",
sqrt(var), sqrt(filter->max_var));
return 0;
}
prev_avg_var = filter->avg_var;
/* update exponential moving average of the variance */