Add localized distribution

Author: PaulZC

docs/img/Displays/SparkFun_RTK_EVK_LBand_Indicator.png

@@ -28,10 +28,32 @@ PointPerfect has the following benefits and challenges:
 
 PointPerfect corrections are obtained by two methods:
 
-* **L-Band**: Corrections are transmitted from a geosynchronous satellite. Coverage areas are limited to the US contiguous 48 states and the EU. This delivery method requires special equipment (see the [RTK Facet L-Band](https://www.sparkfun.com/products/20000) for more information). No cellular or internet connection is required.
+* **L-Band**: Corrections are transmitted from a geosynchronous satellite. Coverage areas are limited to the US contiguous 48 states and the EU. This delivery method requires special equipment (see the [RTK EVK](https://www.sparkfun.com/products/24342) for more information). No cellular or internet connection is required.
 
 * **IP**: Corrections are transmitted over the internet. The RTK device will need access to a WiFi or Ethernet network. For WiFi, this is most commonly a hotspot on a cell phone so this delivery method is generally confined to areas with cellular and/or other WiFi coverage.
 
+## Localized Corrections
+
+The u-blox PointPerfect Localized correction service via MQTT (IP) offers quick delivery of high precision accuracy by providing your device only the SPARTN corrections applicable to your location. This feature offers several advantages over the traditional continental streams, including significantly reduced bandwidth requirements and seamless transition between regions.
+
+* **Reduced bandwidth requirements:** PointPerfect Localized can reduce bandwidth requirements by up to 80%. This is a significant advantage for applications sensitive to bandwidth constraints, such as those that operate in remote areas or use low-power devices.
+
+* **Retained Privacy:** PointPerfect Localized retains user privacy by not sending the device's precise location to the service to receive correction data. This is done by using a general node-based location system.
+
+PointPerfect Localized works by dividing the coverage area into a grid of tiles. Each tile contains a set of nodes that are relevant to a user located within that tile. Unlike the continental level approach where a device subscribes to the continental level topic, in the localized approach a device subscribes to the localized node topic based on its location. This ensures that the device receives only the correction data that is relevant to its location, greatly reducing the required bandwidth.
+
+![Comparison of PointPerfect Localized node density](<img/WiFi Config/SparkFun RTK PointPerfect Config.png>)
+
+*Comparison of PointPerfect Localized node density*
+
+The above image shows the Localized tiles for Level 2 (250 x 250km sparse, ~90-100km separation) vs. Level 5 (250 x 250km high density, ~30km separation).
+
+Localized distribution can be enabled via the serial menu (PointPerfect menu - option 'p'), or the web config page. On serial, option '4' will enable or disable localized distribution; option '5' selects the tile level.
+
+![PointPerfect Menu](<img/Terminal/SparkFun RTK Everywhere - PointPerfect Menu.png>)
+
+*Configuring PointPerfect settings over serial*
+
 ## Registration
 
 ![Three stickers showing Device ID and QR code to registration page](<img/Torch/SparkFun RTK Torch - Device ID Stickers.png>)
@@ -68,18 +90,24 @@ On devices that have a display, the unit will display various prompts to aid the
 
 The *Days until keys expire* inform the user how many days the unit has until it needs to connect to WiFi to obtain new keys.
 
-* **1** - Disable the use of PointPerfect corrections.
+* **1** - Enable / disable the use of PointPerfect corrections.
+
+* **2** - Enable / disable the automatic attempts at WiFi connections when key expiry is less than 28 days.
 
-* **2** - Disable the automatic attempts at WiFi connections when key expiry is less than 28 days.
+* **3** - Trigger an immediate attempt to connect over WiFi / Ethernet and provision the device (if no keys are available) or update the keys (if provisioning has already been completed). Depending on which RTK product you have and which interfaces are connected, it may be necessary to exit the menus for the provisioning / update to take place.
 
-* **3** - Trigger an immediate attempt to connect over WiFi and provision the device (if no keys are available) or update the keys (if provisioning has already been completed).
+* **4** - Enable / disable [localized distribution](#localized-corrections)
 
-* **4** - Display the Device ID. This is needed when a SparkFun RTK device needs to be added to the PointPerfect system. This is needed when first registering the device, or modifying a subscription. [Go here for RTK Torch](https://www.sparkfun.com/rtk_torch_registration) to enable or renew your subscription. [Go here for RTK EVK](https://www.sparkfun.com/rtk_evk_registration) subscriptions.
+* **5** - When localized distribution is enabled, option 5 can be used to select the tile level. The default is Level 5 - 250 x 250km tiles, high density.
 
 * **c** - Clear the current keys.
 
+* **i** - Display the Device ID. This is needed when a SparkFun RTK device needs to be added to the PointPerfect system. This is needed when first registering the device, or modifying a subscription. [Go here for RTK Torch](https://www.sparkfun.com/rtk_torch_registration) to enable or renew your subscription. [Go here for RTK EVK](https://www.sparkfun.com/rtk_evk_registration) subscriptions.
+
 * **k** - Bring up the Manual Key Entry menu.
 
+* **g** - Set the Geographic Region. The default is US; but EU, Australia, Korea and Japan can also be selected. This is an important setting since it sets both the IP distribution topic (MQTT, IP) and the L-Band frequency (RTK EVK).
+
 ## Obtaining the Device ID
 
 The device ID is unique to each RTK device and must be entered by SparkFun into the PointPerfect network. 
@@ -92,7 +120,7 @@ The device ID is unique to each RTK device and must be entered by SparkFun into
 
 *Device ID within the WiFi Config page*
 
-This ID can be obtained by using option **4** from the *PointPerfect* menu or by opening the PointPerfect section within the [WiFi Config](https://docs.sparkfun.com/SparkFun_RTK_Everywhere_Firmware/configure_with_wifi/) interface in the PointPerfect Configuration section.
+This ID can be obtained by using option **i** from the *PointPerfect* menu or by opening the PointPerfect section within the [WiFi Config](https://docs.sparkfun.com/SparkFun_RTK_Everywhere_Firmware/configure_with_wifi/) interface in the PointPerfect Configuration section.
 
 ## Manual Key Entry
 
@@ -110,6 +138,10 @@ Option '1' will allow a user to enter their Device Profile Token. This is the to
 
 *Three-pronged satellite dish indicating L-Band reception*
 
+![Three-pronged satellite dish indicating L-Band reception on EVK](img/Displays/SparkFun_RTK_EVK_LBand_Indicator.png)
+
+*Three-pronged satellite dish indicating L-Band reception on EVK*
+
 On devices that have a display, upon successful reception and decryption of PointPerfect corrections delivered over L-Band, the satellite dish icon will increase to a three-pronged icon. As the unit's fix increases the cross-hair will indicate a basic 3D solution, a double blinking cross-hair will indicate a floating RTK solution, and a solid double cross-hair will indicate a fixed RTK solution.
 
 ## Error Messages
@@ -132,7 +164,7 @@ This message is seen whenever the PointPerfect service is not aware of the given
 
     This device has been deactivated. Please contact [email protected] to renew the PointPerfect subscription. Please reference device ID: [device ID]
 
-This message is seen whenever the device's subscription has lapsed. Please use the [subscription form](https://www.sparkfun.com/pointperfect) or contact [email protected] with your device ID (see [Obtaining the Device ID](menu_pointperfect.md#obtaining-the-device-id) above).
+This message is seen whenever the device's subscription has lapsed. [Go here for RTK Torch](https://www.sparkfun.com/rtk_torch_registration) subscriptions. [Go here for RTK EVK](https://www.sparkfun.com/rtk_evk_registration) subscriptions. Alternatively contact [email protected] with your device ID (see [Obtaining the Device ID](menu_pointperfect.md#obtaining-the-device-id) above).
 
 ### HTTP response error -11 - Read Timeout
 

docs/img/PointPerfect/SparkFun RTK Everywhere - PointPerfect Localized Distribution.png

@@ -148,7 +148,7 @@ Steps to use PointPerfect:
 
     *WiFi Menu containing one network*
 
-5. Under the *PointPerfect Configuration* menu, **Enable PointPefect Corrections** and select your **Geographic Region**. If desired, enable **Localized Corrections** and **AssistNow**.
+5. Under the [*PointPerfect Configuration* menu](menu_pointperfect.md), **Enable PointPefect Corrections** and select your **Geographic Region**. If desired, enable **Localized Corrections** and **AssistNow**.
 
     ![PointPerfect Configuration Menu](<img/WiFi Config/SparkFun RTK PointPerfect Config.png>)