Metrics with Amazon CloudWatch

During a contact, AWS Ground Station automatically captures and sends data to CloudWatch for analysis. Your data can be viewed on a graph or as source code in the Amazon CloudWatch console. For more information about accessing and CloudWatch Metrics, see Using Amazon CloudWatch Metrics.

AWS Ground Station Metrics and Dimensions

What metrics are available?

The following metrics are available from AWS Ground Station.

Metric	Description
AzimuthAngle	The azimuth angle of the antenna. True north is 0 degrees and east is 90 degrees. Units: degrees
BitErrorRate	The error rate on bits in a given number of bit transmissions. Bit errors are caused by noise, distortion, or interference Units: Bits errors per unit time
BlockErrorRate	The error rate of blocks in a given number of received blocks. Block errors are caused by interference. Units: Erroneous blocks / Total number of blocks
CarrierFrequencyRecovery_Cn0	Carrier to noise density ratio per unit bandwidth. Units: decibel-Hertz (dB-Hz)
CarrierFrequencyRecovery_Locked	Set to 1 when the demodulator carrier frequency recovery loop is locked and 0 when unlocked. Units: unitless
CarrierFrequencyRecovery_OffsetFrequency_Hz	The offset between the estimated signal center and ideal center frequency. This is caused by Doppler shift and local oscillator offset between spacecraft and antenna system. Units: hertz (Hz)
ElevationAngle	The elevation angle of the antenna. The horizon is 0 degrees and zenith is 90 degrees. Units: degrees
Es/N0	The ratio of energy per symbol to noise power spectral density. Units: decibels (dB)
ReceivedPower	The measured signal strength in the demodulator/decoder. Units: decibels relative to milliwatts (dBm)
SymbolTimingRecovery_ErrorVectorMagnitude	The error vector magnitude between received symbols and ideal constellation points. Units: percent
SymbolTimingRecovery_Locked	Set to 1 when the demodulator symbol timing recovery loop is locked and 0 when unlocked Units: unitless
SymbolTimingRecovery_OffsetSymbolRate	The offset between the estimated symbol rate and ideal signal symbol rate. This is caused by Doppler shift and local oscillator offset between spacecraft and antenna system. Units: symbols/second

What dimensions are used for AWS Ground Station?

You can filter AWS Ground Station data using the following dimensions.

Dimension	Description
Channel	The channels for each contact include One, Two, I (in-phase), and Q (quadrature).
Polarization	The polarization for each contact include LHCP (Left Hand Circular Polarized) or RHCP (Right Hand Circular Polarized).
SatelliteId	The satellite ID contains the ARN of the satellite for your contacts.

Viewing Metrics

When viewing graphed metrics, it is important to note that the aggregation window determines how your metrics will be displayed. Each metric in a contact can be displayed as data per second for 3 hours after the data is received. Your data will be aggregated by CloudWatch Metrics as data per minute after that 3 hour period has elapsed. If you need to view your metrics on a data per second measurement, it is recommended to view your data within the 3 hour period after the data is received or persist it outside of CloudWatch Metrics.

In addition, any data captured within the first 60 seconds will not contain enough information to produce meaningful metrics, and will likely not be displayed. In order to view meaningful metrics, it is recommended to view your data after 60 seconds has passed.

For more information about graphing AWS Ground Station metrics in CloudWatch, see Graphing Metrics.

To view metrics using the console

1. Open the CloudWatch console at https://console.aws.amazon.com/cloudwatch/.

2. In the navigation pane, choose Metrics.

3. Select the GroundStation namespace.

   

4. Select your desired metric dimensions (for example, Channel, Polarization, SatelliteId.

   

5. The All metrics tab displays all metrics for that dimension in the namespace. You can do the following:

   1. To sort the table, use the column heading.

   2. To graph a metric, select the check box associated with the metric. To select all metrics, select the check box in the heading row of the table.

   3. To filter by resource, choose the resource ID and then choose Add to search.

   4. To filter by metric, choose the metric name and then choose Add to search.

To view metrics using AWS CLI

1. Ensure that AWS CLI is installed. For information about installing AWS CLI, see Installing the AWS CLI version 2.

2. Create a CloudWatch agent configuration JSON file. For instructions on creating a CloudWatch agent configuration file, see Create the CloudWatch Agent Configuration File.

3. List the available CloudWatch metrics by running aws cloudwatch list-metrics.

4. Modify the JSON file you created in step 2 to match the SatellitID from your metrics.

   Note

   Do not reduce the Period field to a value under 60. AWS Ground Station publishes metrics every 60 seconds and no metrics will be returned if the value is reduced.

5. Run aws cloudwatch get-metric-data with time periods of your passes and your CloudWatch agent configuration JSON file. An example is provided below.

   aws cloudwatch get-metrics-data –start-time 2020-02-26T19:12:00Z –end-time 2020-02-26T19:24:00Z –metric-data-queries file://metricdata.json

Metrics will be provided with timestamps from your contact. An example output of AWS Ground Station metrics is provided below.

{
      “MetricDataResults”: [
          {
              “Id”: “myQuery”,
              “Label”: “Es/N0”,
              “Timestamps”: [
                  “2020-02-18T19:44:00Z”,
                  “2020-02-18T19:43:00Z”,
                  “2020-02-18T19:42:00Z”,
                  “2020-02-18T19:41:00Z”,
                  “2020-02-18T19:40:00Z”,
                  “2020-02-18T19:39:00Z”,
                  “2020-02-18T19:38:00Z”,
                  “2020-02-18T19:37:00Z”,
              ],
              “Values”: [
                  24.58344556958329,
                  24.251638725562216,
                  22.919391450230158,
                  22.83838908204037,
                  23.303086848486842,
                  22.845261784583364,
                  21.34531397048953,
                  19.171561698261222
              ],
              “StatusCode”: “Complete”
          }
      ]
      “Messages”: []
}