u-blox LEA-6H Module Firmware 7.03

New features:

- AssistNow Autonomous
The "AssistNow Autonomous" feature provides functionality similar to A-GPS (AssistNow Online, AssistNow Offline) without the need of a host and data connection. Based on a broadcast ephemeris downloaded from the satellite (or obtained by A-GPS) the receiver can autonomously (i.e. without any host interaction or online connection) generate an accurate satellite orbit model that is usable for navigation much longer than the underlying ephemeris was intended for. This satellite orbit model is stored as AssistNow Autonomous data in the receiver’s Battery Backup RAM and can be used for subsequent first fixes (e.g. for the next day). The use of AssistNow Autonomous makes obtaining live satellite ephemeris unnecessary for the first fix after start-up and hence reduces the time to first fix (TTFF). As an alternative to storing the AssistNow Autonomous data in BBR, it can be stored either to external flash memory or host processor. The feature can be enabled using the UBX-CFG-NAVX5 message (it is disabled by default). The UBX-NAV-AOPSTATUS message provides information on the status of the subsystem and the availability of data per satellite. The UBX-AID-AOP message provides a host interface for data, and the UBX-NAV-SVINFO indicates the use of AssistNow Autonomous orbits.

- Map matching input

Map matching input is only available with u-blox Automotive Dead Reckoning (ADR) functionality.
The map matching input feature allows feeding a map matched position solution back to the receiver in order to aid its next navigation solution. Map matching data contributes to improved positioning performance. However, the result using map matching depends directly on the quality of the map data used, i.e. bad or outdated data will corrupt or downgrade performance. Data can be supplied using the UBX-AID-MAPM input message.

- Save Almanac and AssistNow Autonomous data to NVS

The message UBX-CFG-NVS allow storing AssistNow Autonomous data to external flash memories. Note, dumped data from a receiver shall not be transferred to other receivers as it contains device specific data, e.g. oscillator offset.

- TX ready signal

The TX ready signal indicates that the receiver has data to transmit. A listener can wait on the TX ready signal instead of polling the DDC or SPI interfaces. The UBX-CFG-PRT message allows configuration of the polarity and the number of bytes in the buffer before the ready signal goes active. The TX ready signal can be mapped to any GPIO. TIMEPULSE is not a GPIO and cannot be used as a TX ready pin! The TX ready pin is disabled by default.

- RTCM 2.3

DGPS on FW7.01 requires no configuration to work properly. When an RTCM stream is input on any of the communication interfaces, the data will be parsed and applied if possible, putting the receiver into DGPS mode. RTCM protocol must be enabled on the interface being used with CFG-PRT. The only configurable parameter of the DGPS mode in FW7.01 is the DGPS timeout that can be specified using CFG-NAV5. This value defines the time before old RTCM data will be discarded.
The DGPS solution only includes measurements from satellites for which DGPS corrections were provided. This is because the navigation algorithms cannot mix corrected with uncorrected measurements.
SBAS corrections will not be applied when using RTCM correction data
RTCM correction data cannot be applied when using AssistNow Offline or AssistNow Autonomous
RTCM support is implemented according to RTCM 10402.3: "RECOMMENDED STANDARDS FOR DIFFERENTIAL GNSS"

- Jamming/Interference Monitor

The Jamming/Interference Monitor indicates if the receiver suspects the presence of in-band broadband or CW jamming. This is well suited for security and automotive customers as an indication of intentional external jamming.
The indicator has four states:
Unknown - jammer detection not enabled, uninitialized, or antenna disconnected
OK - no interference detected
Warning - position ok but interference is visible (above the thresholds)
Critical - no position and interference is visible (above the thresholds), probably reason there is no fix
The indicator is part of the UBX message MON-HW. Normally, with no interference detected, it will report 'OK'.
The indicator is disabled by default and is enabled by sending an appropriate CFG-ITFM UBX message. This message also specifies the thresholds at which broadband and CW jamming are reported and whether the receiver has an Active or Passive antenna connected.
The indicator algorithm relies on comparing the current measured spectrum with one for which a good fix was obtained. Therefore the indicator will only function once the receiver has had at least one successful first fix, and reports 'Unknown' before this time.

- Time aiding error message

A UBX message UBX-TIM-VRFY has been implemented which outputs the error of the time aiding as done with the UBX-AID-INI message.

Improvements and changes

- Power Save Mode configuration
The configuration message CFG-PM remains unchanged from FW6.02. When using CFG-PM with FW7.01, the new algorithms built into FW7.01 are selected and configured to provide best performance while at the same time providing a maximum of backwards compatibility with FW6.02.

- New CFG-PM2 configuration message

CFG-PM2 allows configuring new settings of FW7.01:
Select operation mode: on/off operation or cyclic tracking operation. The selection of the operation mode influences the possible position update period that can be set:
- on/off operation allows update periods larger than 5000 ms
- cyclic operation allows update periods between 1000 ms to 10000 ms.
- New: the user can influence the behavior of the receiver in case it can't get a position fix while in PSM: If the flag “doNotEnterOff” (in u-center the flag is called “Do not enter inactive for search state when no fix”) is set, the receiver does not enter inactive for search state but keeps trying to acquire a position fix.

- Behavior while USB host connected

As long as the receiver is connected to a USB host, it will not enter backup state. Instead, CPU-only state is entered. This ensures that the USB specification is not violated, however the power consumption is higher.
Wake-up by pin/UART/USB is possible, even if receiver is in CPU-only state.

- UBX-RXM-PMREQ message applicable during PSM

With message UBX-RXM-PMREQ it is possible to overrule PSM and force the receiver to enter backup state.

Performance:

- Tracking sensitivity
The tracking sensitivity has been increased up to 2dB compared to FW6.02.

- Improved Anti-Jamming by better CW / narrow band interferer mitigation

A new narrow band and comb interferer mitigation algorithm has been added, which results in even better jamming mitigation.

- Acquisition and re-acquisition improvements

Hot start and re-acquisition sensitivity and acquisition time has been improved particularly in low dynamic scenarios.

- Improved velocity solution

Various measures have been taken to improve the accuracy of the velocity output, especially for receivers with crystal oscillator and in high dynamic scenarios.

- Bad 2D fixes at startup

In previous firmware revisions, bad 2D solutions became unmasked after some observation time. With FW 7.03, 2D fixes calculated with an inaccurate altitude will stay masked over time.

- New time mode for u-blox Timing receivers

A new CFG-TMODE2 message has been defined to allow for larger position uncertainty and for supplying the position in Lat/Lon/Alt format.
T-RAIM has been significantly improved for 1-3 SVs
The accuracy estimation for the survey-in position has been improved to better reflect field situations in order to avoid problems in degraded signal scenarios. Customers currently using survey-in need to review their accuracy limit setting with CFG-TMODE or CFG-TMODE2.