Whether API 1.5 is backward-compatible with an integration developed against API 1.3.
Yes, API should be backwards compatible. New configuration options typically add additional keys and sometimes enum values. The latest version of the integration guide can be found here: glrm-integration-fw1.11p2.pdf - General Laser
Whether any BLE UUIDs, framing, position/status fields, units or enumerations have changed.
No, BLE UUIDS, framing and the position broadcast message has not changed. The position solution (pos.sol) has to new possible values: ppp converging (4) und ppp (5), see the updated integration guide for details.
Whether updating can reset the receiver configuration.
Yes, updating the receiver can reset the configuration. Most firmware updates, especially if new features are added, reset all configuration of the GLRM to there factory default values. Additionally, some factory default values, like the “standy_timeout” in the device configuration, have changed as well. The latest version of the integration guide documents the factory-default values, and will also report future changes in the changelog.
Whether 1.11p1 is fully supported on HW 5.0.
Yes, firmware version 1.11p1 is fully supported on hardware 5.0. For integrators we already have firmware version 1.11p2 as pre-release available for testing, the new features are: USB-power configuration (always-on, …), reboot and factory reset commands.
To get access to the pre-release firmware versions for integrator testing, please create an account in the GL-Connect app and tell us the accounts email-address, so we can give the account integrator access permissions.
Base Station
No, a base station mode for the GLRM is not available and not planned.
Recommended BLE MTU and notification payload assumptions, including handling fragmented or combined protocol frames.
The maximum MTU size for the GLRM is 247, which gives a maximum data size of 245 bytes per package. I would recommend using a MTU size of 247.
Recommended RTCM write chunk size, pacing, flow control and queue/back-pressure behavior when using Write Without Response.
Chunks can be as big as MTU allows, so up to 245 bytes. Chunks can be sent at full BLE speed, GLRM internally buffers the RTCM message and drops all invalid/incomplete messages.
Whether the GLRM supports only one BLE central at a time and how connections from SiteNav, GL Connect, Bluetooth Classic and serial interfaces are expected to interact.
GLRM supports multiple interfaces at once. For example, streaming RTCM to the GLRM via BLE and receiving data from the GLRM via Bluetooth Classic is fully supported. If position output is streaming on multiple interfaces at once, the output rate is not individually configurable. Currently, configuration is only supported via BLE, but configuration support for Bluetooth Classic (and later also serial) is planned.
The preferred reconnect and state-restoration behaviour following an unexpected Bluetooth interruption.
Our recommendation would be that the app automatically reconnects to the GLRM. If the RTCM data stream is interrupted for less than 10s, RTK FIX should not be lost.