DOCS-1499: Document dual-gps-rtk model of movement sensor (viamrobo…

…tics#2594)

docs/components/movement-sensor/_index.md

@@ -47,6 +47,7 @@ Model | Description <a name="model-table"></a>
 [`gps-nmea`](./gps/gps-nmea/) | [NMEA-based](https://en.wikipedia.org/wiki/NMEA_0183) GPS models
 [`gps-nmea-rtk-pmtk`](./gps/gps-nmea-rtk-pmtk/) | [NTRIP-based](https://en.wikipedia.org/wiki/Networked_Transport_of_RTCM_via_Internet_Protocol) [RTK](https://en.wikipedia.org/wiki/Real-time_kinematic_positioning) GPS models using I<sup>2</sup>C (**experimental**)
 [`gps-nmea-rtk-serial`](./gps/gps-nmea-rtk-serial/) | [NTRIP-based](https://en.wikipedia.org/wiki/Networked_Transport_of_RTCM_via_Internet_Protocol) [RTK](https://en.wikipedia.org/wiki/Real-time_kinematic_positioning) GPS models using serial communication (**experimental**)
+[`dual-gps-rtk`](./gps/dual-gps-rtk/) | A movement sensor that calculates compass heading from two GPS movement sensors
 [`imu-wit`](./imu/imu-wit/) | IMUs manufactured by [WitMotion](https://www.wit-motion.com/)
 [`accel-adxl345`](./adxl345/) | The [Analog Devices ADXL345](https://www.analog.com/en/products/adxl345.html) digital accelerometer
 [`gyro-mpu6050`](./mpu6050/) | A gyroscope/accelerometer manufactured by TDK InvenSense

docs/components/movement-sensor/gps/dual-gps-rtk.md

@@ -0,0 +1,114 @@
+---
+title: "Configure a Dual GPS Movement Sensor"
+linkTitle: "dual-gps-rtk"
+weight: 10
+type: "docs"
+description: "Configure a movement sensor that calculates compass heading from two gps movement sensors."
+images: ["/icons/components/imu.svg"]
+# SMEs: Rand
+---
+
+The `dual-gps-rtk` model of movement sensor calculates compass heading from two GPS movement sensors, and returns the midpoint position between the first and second GPS devices as its position.
+In addition to [`GetCompassHeading()`](/components/movement-sensor/#getcompassheading), this model provides data for [`GetPosition()`](/components/movement-sensor/#getposition) and [`GetAccuracy()`](/components/movement-sensor/#getaccuracy).
+
+{{< tabs >}}
+{{% tab name="Config Builder" %}}
+
+Navigate to the **Config** tab of your machine's page in [the Viam app](https://app.viam.com).
+Click on the **Components** subtab and click **Create component**.
+Select the `movement-sensor` type, then select the `dual-gps-rtk` model.
+Enter a name for your movement sensor and click **Create**.
+
+![Creation of a `dual-gps-rtk` movement sensor in the Viam app config builder.](/components/movement-sensor/dual-gps-rtk-builder.png)
+
+Copy and paste the following attribute template into your movement sensor's **Attributes** box.
+Then remove and fill in the attributes as applicable to your movement sensor, according to the table below.
+
+{{< tabs >}}
+{{% tab name="Attributes template" %}}
+
+```json {class="line-numbers linkable-line-numbers"}
+{
+  "first_gps": "<name-of-your-first-gps-movement-sensor>",
+  "second_gps": "<name-of-your-second-gps-movement-sensor>",
+  "offset_degrees": <int>
+}
+```
+
+{{% /tab %}}
+{{% tab name="Attributes example" %}}
+
+```json {class="line-numbers linkable-line-numbers"}
+{
+  "first_gps": "nmea-1",
+  "second_gps": "nmea-2",
+  "offset_degrees": 90
+}
+```
+
+{{% /tab %}}
+{{< /tabs >}}
+
+{{% /tab %}}
+{{% tab name="JSON Template" %}}
+
+```json {class="line-numbers linkable-line-numbers"}
+{
+  "components": [
+    {
+      "name": "your-dual-gps-rtk",
+      "model": "dual-gps-rtk",
+      "type": "movement_sensor",
+      "namespace": "rdk",
+      "attributes": {
+        "first_gps": "<name-of-your-first-gps-movement-sensor>",
+        "second_gps": "<name-of-your-second-gps-movement-sensor>",
+        "offset_degrees": <int>
+      },
+      "depends_on": []
+    }
+  ]
+}
+```
+
+{{% /tab %}}
+{{% tab name="JSON Example" %}}
+
+```json {class="line-numbers linkable-line-numbers"}
+{
+  "components": [
+    {
+      "name": "your-dual-gps-rtk",
+      "model": "dual-gps-rtk",
+      "type": "movement_sensor",
+      "namespace": "rdk",
+      "attributes": {
+        "first_gps": "nmea-1",
+        "second_gps": "nmea-2",
+        "offset_degrees": 90
+      },
+      "depends_on": []
+    }
+  ]
+}
+```
+
+{{% /tab %}}
+{{< /tabs >}}
+
+The following attributes are available for a `dual-gps-rtk` movement sensor:
+
+<!-- prettier-ignore -->
+| Name | Type | Inclusion | Description |
+| ---- | ---- | --------- | ----------- |
+| `first_gps` | int | **Required** | The name you have configured for the first movement sensor you want to combine the measurements from. Must be a GPS model. |
+| `second_gps` | string | **Required** | The name you have configured for the second movement sensor you want to combine the measurements from. Must be a GPS model. |
+| `offset_degrees` | int | Optional | The value to offset the compass heading calculation between the two GPS devices based on their positions on the base. Calculate this as the degrees between the vector from `first_gps` to `second_gps` and the vector from the vehicle's back to the vehicle's front, counterclockwise. {{< imgproc src="/components/movement-sensor/offset_degrees.png" alt="Rand's diagram of 3 offset degree calculations." resize="600x" >}} <br> Default: `90` |
+
+## Test the movement sensor
+
+After you configure your movement sensor, navigate to the [Control tab](/fleet/machines/#control) and select the dedicated movement sensor dropdown panel.
+This panel presents the data collected by the movement sensor.
+The sections in the panel include the position, compass heading, and accuracy.
+
+{{<imgproc src="/components/movement-sensor/movement-sensor-control-tab-dual.png" resize="800x" declaredimensions=true alt="The dual GPS movement sensor component in the control tab">}}