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u-blox F9 Integration Manual

u-blox F9 Integration Manual

High accuracy timing module
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ZED-F9T
u-blox F9 high accuracy timing module
Integration manual
Abstract
This document describes the features and application of ZED-F9T, a multi-
band GNSS module offering nano-second level timing accuracy.
www.u-blox.com
UBX-21040375 - R02
C1-Public

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  • Page 1  ZED-F9T u-blox F9 high accuracy timing module Integration manual Abstract This document describes the features and application of ZED-F9T, a multi- band GNSS module offering nano-second level timing accuracy. www.u-blox.com UBX-21040375 - R02 C1-Public...

  • Page 2: Document Information

    fitness for a particular purpose of the information. This document may be revised by u-blox at any time without notice. For the most recent documents, visit www.u-blox.com.

  • Page 3: Table Of Contents

    ZED-F9T - Integration manual Contents 1 Integration manual overview..................... 6 2 System description.......................7 2.1 Overview..............................7 2.1.1 Differential timing.......................... 7 2.2 Architecture..............................8 2.2.1 Block diagram..........................8 3 Receiver functionality......................9 3.1 Receiver configuration........................... 9 3.1.1 Changing the receiver configuration..................9 3.1.2 Default GNSS configuration......................9 3.1.3 Default interface settings......................10 3.1.4 Basic receiver configuration......................
  • Page 4 3.11.2 Jamming and interference detection and monitoring............51 3.11.3 Spoofing and jamming indication..................52 3.11.4 GNSS receiver security......................52 3.11.5 Galileo Open Service Navigation Message Authentication (OSNMA)......53 3.12 u-blox protocol feature descriptions....................56 3.12.1 Broadcast navigation data...................... 56 3.12.2 Save-on-shutdown feature...................... 65 3.12.3 Spectrum analyzer........................65 3.12.4 Sky view signal masking......................
  • Page 5 ZED-F9T - Integration manual 4.6.2 In-band interference mitigation....................82 4.6.3 Out-of-band interference......................82 4.7 Layout..............................83 4.7.1 Placement............................83 4.7.2 Thermal management........................ 83 4.7.3 Package footprint, copper and paste mask................83 4.7.4 Layout guidance........................... 85 4.8 Design guidance............................87 4.8.1 General considerations....................... 87 4.8.2 Backup battery..........................87 4.8.3 RF front-end circuit options......................

  • Page 6: Integration Manual Overview

    ZED-F9T - Integration manual 1 Integration manual overview This document is an important source of information on all aspects of ZED-F9T system, software and hardware design. The purpose of this document is to provide guidelines for a successful integration of the receiver with the customer's end product. UBX-21040375 - R02 1 Integration manual overview Page 6 of 100...

  • Page 7: System Description

    22 x 17 mm. 2.1.1 Differential timing The u-blox ZED-F9T high accuracy timing receiver takes local timing accuracy to the next level with its differential timing mode. In differential timing mode correction data is exchanged with other neighboring ZED-F9T timing receivers via a communication network.

  • Page 8: Architecture

    ZED-F9T - Integration manual 2.2 Architecture The ZED-F9T receiver provides all the necessary RF and baseband processing to enable multi-band, multi-constellation operation. The block diagram below shows the key functionality. 2.2.1 Block diagram Figure 1: ZED-F9T block diagram An active antenna is mandatory with ZED-F9T. UBX-21040375 - R02 2 System description Page 8 of 100...

  • Page 9: Receiver Functionality

    BBR (battery-backed RAM), the setting will be used as long as the backup battery supply remains. Configuration settings can be saved permanently in flash memory. CAUTION The configuration interface has changed from earlier u-blox positioning receivers. Legacy messages have been deprecated and are not supported in TIM 2.24 and later firmware releases.

  • Page 10: Default Interface Settings

    ZED-F9T - Integration manual • BeiDou: B1I, B2a • QZSS: L1C/A, L5 ZED-F9T-20B: • GPS: L1C/A • Galileo: E1B/C, E5a • BeiDou: B1I, B1C, B2a • QZSS: L1C/A, L5 The NavIC L5 signal is supported by the ZED-F9T-10B and ZED-F9T-20B, but not enabled in the default GNSS configuration.
  • Page 11 ZED-F9T - Integration manual 3.1.4.1 Communication interface configuration Several configuration groups allow operation mode configuration of the various communication interfaces. These include parameters for the data framing, transfer rate and enabled input/output protocols. See Communication interfaces section for details. The configuration groups available for each interface are: Interface Configuration groups...
  • Page 12 ZED-F9T - Integration manual • Control voltage supply to the antenna, which allows the antenna supervisor to cut power to the antenna in the event of a short circuit or optimize power to the antenna in power save mode • Detect a short circuit in the antenna and auto recover the antenna supply in such an event •...

  • Page 13: Differential Timing Mode Configuration

    RTCM 1127 BeiDou MSM7 RTCM 1230 GLONASS code-phase biases RTCM 4072.1 Additional reference station information (u-blox proprietary RTCM Message) Table 5: ZED-F9T supported input RTCM version 3.4 messages 3.1.5.3 List of supported RTCM output messages Message type Description RTCM 1005...
  • Page 14 ZED-F9T - Integration manual time accuracy, for single-SV solutions, and also for using the receiver as a stationary reference station. In order to use time mode, the receiver's position must be known as exactly as possible. Errors in the fixed position will translate into time errors depending on the satellite constellation. The following procedures can be used to initialize the timing receiver position: •...
  • Page 15 ZED-F9T - Integration manual Configuration item Description CFG-TMODE-ECEF_X_HP High-precision ECEF X coordinate of the ARP position, coordinate in 0.1 millimeters CFG-TMODE-ECEF_Y_HP High-precision ECEF Y coordinate of the ARP position, coordinate in 0.1 millimeters CFG-TMODE-ECEF_Z_HP High-precision ECEF Z coordinate of the ARP position, coordinate in 0.1 millimeters CFG-TMODE-LAT_HP High-precision latitude of the ARP position, coordinate in 1e-9 degrees CFG-TMODE-LON_HP...

  • Page 16: Primary And Secondary Output

    3.1.6 Primary and secondary output 3.1.6.1 Introduction u-blox GNSS receivers output various navigation results and data calculated as part of the navigation solution. These include results such as position, altitude, velocity, status flags, accuracy estimate figures, satellite/signal information and more.
  • Page 17 ZED-F9T - Integration manual • Optionally, configuring the properties of the secondary output navigation solution The configuration items relevant to the secondary output are in the CFG-NAV2-* configuration group. The configuration items for enabling and configuring the output rate of the UBX-NAV2-* messages are in the CFG-MSGOUT-* group and are of the form CFG-MSGOUT-UBX_NAV2_*.

  • Page 18: Legacy Configuration Interface Compatibility

    CFG-MOT-*. 3.1.8.1 Platform settings u-blox receivers support different dynamic platform models (see the table below) to adjust the navigation engine to the expected application environment. These platform settings can be changed dynamically without performing a power cycle or reset. The settings improve the receiver's interpretation of the measurements and thus provide a more accurate position output.
  • Page 19 ZED-F9T - Integration manual The dynamic platform model can be configured through the CFG-NAVSPG-DYNMODEL configuration item. The supported dynamic platform models and their details can be seen in Table Table 12 below. Platform Description Portable Applications with low acceleration, e.g. portable devices. Suitable for most situations. Stationary (default) Used in timing applications (antenna must be stationary) or other stationary applications.
  • Page 20 3D fix (min four satellites available), the altitude is kept constant at the last known value. This is called a 2D fix. u-blox receivers do not calculate any navigation solution with less than three satellites. Time solution can be calculated with 1-2 satellites.
  • Page 21 ZED-F9T - Integration manual 3.1.8.3.3 Low-speed course over ground filter The CFG-ODO-USE_COG activates a low-speed course over ground filter and the CFG-ODO- COGMAXSPEED, CFG-ODO-COGMAXPOSACC configuration items offer the possibility to configure this feature (also named heading of motion 2D). This filter derives the course over ground from position at very low speed.
  • Page 22 ZED-F9T - Integration manual Figure 3: Flowchart of the static hold mode 3.1.8.5 Freezing the course over ground If the low-speed course over ground filter is deactivated or inactive (see section Low-speed course over ground filter), the receiver derives the course over ground from the GNSS velocity information. If the velocity cannot be calculated with sufficient accuracy (e.g., with bad signals) or if the absolute speed value is very low (under 0.1 m/s) then the course over ground value becomes inaccurate too.

  • Page 23: Sbas

    ZED-F9T - Integration manual Figure 4: Flowchart of the course over ground freezing 3.2 SBAS Whilst the ZED-F9T can make use of SBAS satellites, experience has shown that employing these signals can degrade the timing performance and hence SBAS use is not enabled by default. The following section describes the receiver operation when SBAS reception is required by users.
  • Page 24 Europe, therefore it is recommended that the satellites from all but the EGNOS system should be disallowed using the PRN mask. Although u-blox receivers try to select the best available SBAS correction data, it is recommended to configure them to exclude unwanted SBAS satellites.

  • Page 25: Geofencing

    ZED-F9T - Integration manual SBAS is only used if no correction service is available. If the connection stream is lost during the operation, the receiver will switch to using the SBAS corrections after the time set in CFG- NAVSPG-CONSTR_DGNSSTO (60 s by default) has elapsed. When the receiver switches from a solution using correction data to a standard position solution, the reference frame of the output position will switch from the one of the correction data to that of the standard position solution.

  • Page 26: Using A Pio For Geofence State Output

    ZED-F9T - Integration manual Figure 6: Geofence states The combined state for all geofences is evaluated as the combination (Union) of all geofences: • Inside - The position lies inside of at least one geofence • Outside - The position lies outside of all geofences •...

  • Page 27: Information About The Log

    ZED-F9T - Integration manual messages will be rejected with a UBX-ACK-NAK message if there is no log present. Only one log can be created at any one time so a UBX-ACK-NAK message will be returned if a log already exists. The message specifies the maximum size of the log in bytes (with some preset values provided). Both the logging subsystem and the receiver file-store have implementation overheads, so the total space available for log entries will be somewhat smaller than the size specified.

  • Page 28: Recording

    ZED-F9T - Integration manual For example, if 1500 kB of flash is available for logging (after other flash usage such as the firmware image is taken into account) a non-circular log would be able to contain approximately 139000 entries: ((1500*1024)- (8*1024))/11 = 138891. 3.4.4 Recording The CFG-LOGFILTER-RECORD_ENA configuration item must be set to true to enable recording into the log.

  • Page 29: Retrieval

    ZED-F9T - Integration manual Figure 8: The states of the active logging subsystem 3.4.5 Retrieval UBX-LOG-RETRIEVE starts the process which allows the receiver to output log entries. UBX-LOG- INFO may be helpful to a host system in order to understand the current log status before retrieval is started.

  • Page 30: Communication Interfaces

    Also a command queue overflow would result in commands being lost. 3.5 Communication interfaces u-blox receivers are equipped with a communication interface which is multi-protocol capable. The interface ports can be used to transmit GNSS measurements, monitor status information and configure the receiver.

  • Page 31: Uart

    ZED-F9T - Integration manual Figure 9: ZED-F9T output isolation Figure 10: ZED-F9T input isolation 3.5.1 UART A Universal Asynchronous Receiver/Transmitter (UART) port consists of an RX and a TX line. Neither handshaking signals nor hardware flow control signals are available. The UART interface protocol and baud rate can be configured but there is no support for setting different baud rates for reception and transmission.

  • Page 32: I2C Interface

    To use the I2C interface D_SEL pin must be left open. In designs where the host uses the same I2C bus to communicate with more than one u-blox receiver, the I2C peripheral address for each receiver must be configured to a different value.
  • Page 33 ZED-F9T - Integration manual The register at address 0xFF allows the data stream to be read. If there is no data awaiting transmission from the receiver, then this register delivers value 0xFF, which cannot be the first byte of a valid message. If the message data is ready for transmission, the successive reads of register 0xFF will deliver the waiting message data.
  • Page 34 ZED-F9T - Integration manual Figure 12: I2C random read access If the second form, "current address" is used, an address pointer in the receiver is used to determine which register to read. This address pointer will increment after each read unless it is already pointing at register 0xFF, the highest addressable register, in which case it remains unaltered.

  • Page 35: Spi Interface

    ZED-F9T - Integration manual Figure 14: I2C write access 3.5.3 SPI interface ZED-F9T has an SPI peripheral interface that can be selected by setting D_SEL = 0. The SPI peripheral interface is shared with UART1 and I2C port, the physical pins are same. The SPI pins available are: •...

  • Page 36: Usb Interface

    ZED-F9T - Integration manual Figure 15: SPI back-to-back read/write access 3.5.4 USB interface A single USB port is provided for host communication purposes. The USB 2.0 FS (Full speed, 12 Mbit/s) interface can be used for host communication. Due to the hardware implementation, it may not be possible to certify the USB interface. If the receiver executes code from internal ROM (i.e.

  • Page 37: Predefined Pios

    ZED-F9T - Integration manual Figure 16: ZED-F9T example circuit for USB interface R11 = 100 k Ω is recommended R4, R5 = 27 Ω is recommended 3.6 Predefined PIOs In addition to the communication ports, there are some predefined PIOs provided by ZED-F9T to interact with the receiver.

  • Page 38: Timepulse

    ZED-F9T - Integration manual It is recommended to have the possibility to pull the SAFEBOOT_N pin low in the application. This can be provided using an externally connected test point or a host I/O port. 3.6.4 TIMEPULSE The ZED-F9T provides time pulse signals on the TIMEPULSE and TIMEPULSE2 pins. More information about the time pulse feature and its configuration can be found in the Time pulse section.

  • Page 39: Antenna Short Detection - Ant_Short_N

    ZED-F9T - Integration manual $GNTXT,01,01,02,ANTSTATUS=INIT*3B $GNTXT,01,01,02,ANTSTATUS=OK*25 ANTSUPERV=AC indicates antenna control is activated 3.7.2 Antenna short detection - ANT_SHORT_N Enable antenna short detection setting configuration item CFG-HW- ANT_CFG_SHORTDET to true (1). Result: • UBX-MON-RF in u-center "Message View": Antenna status = OK. Antenna power status = ON •...

  • Page 40: Antenna Open Circuit Detection - Ant_Detect

    Then if ANT_DETECT is left floating or it is pulled high to indicate antenna connected: $GNTXT,01,01,02,ANTSTATUS=OK*25 3.8 Multiple GNSS assistance (MGA) The u-blox AssistNow services provide a proprietary implementation of an A-GNSS protocol compatible with u-blox GNSS receivers. The MGA services consist of AssistNow Online and Offline variants delivered by HTTP or HTTPS protocol.

  • Page 41: Authorization

    The ZED-F9T supports AssistNow Online only. 3.8.1 Authorization To use the AssistNow services, customers will need to obtain an authorization token from u-blox. Go to https://www.u-blox.com/en/solution/services/assistnow or contact your local technical support to get more information and to request access to the service.

  • Page 42: Navigation Epochs

    ZED-F9T - Integration manual receiver obtains some credible timing information from a satellite or an aiding message, it will jump to an estimate of GNSS time. 3.9.2 Navigation epochs Each navigation solution is triggered by the tick of the 1-kHz clock nearest to the desired navigation solution time.

  • Page 43: Gnss Times

    ZED-F9T - Integration manual accuracy in UBX-NAV-PVT) of the calculated times (see also the GNSS times section below for further messages containing time information). 3.9.4 GNSS times Each GNSS has its own time reference for which detailed and reliable information is provided in the messages listed in the table below.

  • Page 44: Leap Seconds

    23:59:58 will be followed by 00:00:00. u-blox receivers are designed to handle leap seconds in their UTC output and consequently users processing UTC times from either NMEA or UBX messages should be prepared to handle minutes that are either 59 or 61 seconds long.

  • Page 45: Date

    GLONASS, BeiDou and Galileo to be unambiguous and, where necessary, use this to resolve any ambiguity in the GPS date. Customers attaching u-blox receivers to simulators should be aware that GPS time is referenced to 6th January 1980, GLONASS to 1st January 1996, Galileo to 22nd August 1999 and BeiDou to 1st January 2006;...

  • Page 46: Time Pulse

    ZED-F9T - Integration manual standards that utilize Time Division Multiplex (TDM) and applications such as femtocell base stations, a precision time reference is mandatory. 3.10.1 Time pulse 3.10.1.1 Introduction The ZED-F9T receiver includes two time pulse outputs with configurable duration and frequency. The time pulse function can be configured using the CFG-TP-* configuration group for the desired time pulse;...
  • Page 47 Although u-blox receivers can combine a variety of different GNSS times internally, the user must choose a single type of GNSS time and, separately, a single type of UTC for input (on EXTINT pins) and output (via the TIMEPULSE pin) and the parameters reported in corresponding messages.
  • Page 48 ZED-F9T - Integration manual 3.10.1.4 Time pulse configuration u-blox ZED-F9T receivers provide a time pulse (TIMEPULSE) signal with a configurable pulse period, length and polarity (rising or falling edge). It is possible to define different signal behavior (i.e. output frequency and pulse length) depending on whether or not the receiver is locked to a reliable time source.

  • Page 49: Time Mark

    ZED-F9T - Integration manual • CFG-TP-TP1_ENA = 1 • CFG-TP-PULSE_DEF = 0 (PERIOD) • CFG-TP-PULSE_LENGTH_DEF = 1 (LENGTH) • CFG-TP-PERIOD_TP1 = 1 000 000 µs • CFG-TP-LEN_TP1 = 100 000 µs • CFG-TP-TIMEGRID_TP1 = 1 (GPS) • CFG-TP-ALIGN_TO_TOW_TP1 = 1 • CFG-TP-USE_LOCKED_TP1 = 1 •...

  • Page 50: Time Mark For Common View Time Transfer

    ZED-F9T - Integration manual Figure 20: Time mark 3.10.3 Time mark for Common View Time Transfer Common view time transfer (CVTT) allows comparison of geographically widely spaced clocks by comparing GNSS signal times observed at each location with respect to a time pulse provided, for example, by a site reference clock.

  • Page 51: Security

    Intentional and/or unintentional jamming of GNSS receivers can degrade the quality of GNSS signals and receiver performance. All u-blox receivers can detect and monitor jamming and report it to the user. The monitoring function is always enabled to inform the user about interference in the GNSS RF bands.

  • Page 52: Spoofing And Jamming Indication

    See the applicable Interface description [2]. 3.11.4 GNSS receiver security 3.11.4.1 Secure boot The ZED-F9T boots only with firmware images that are signed by u-blox. This prevents the execution of non-genuine firmware images on the receiver. 3.11.4.2 Secure firmware update The firmware image is signed by u-blox.

  • Page 53: Galileo Open Service Navigation Message Authentication (Osnma)

    ZED-F9T - Integration manual An example of use case is that the host application locks the receiver configuration. A user communicating with the ZED-F9T through any of the available interfaces can poll, enable or send messages, but cannot change the configuration by sending UBX configuration messages. 3.11.5 Galileo Open Service Navigation Message Authentication (OSNMA) This feature is available as of firmware version TIM 2.24.
  • Page 54 ZED-F9T - Integration manual OSNMA Cryptographic keys Description UBX-MGA-GAL-OSNMA_PUBKEY To avoid waiting for the Public Key to be transmitted in the signal, it can be sent to the receiver with the UBX-MGA-GAL-OSNMA_PUBKEY message. This message requires the corresponding Public Key ID (PKID), the hash function with which the Public Key is hashed (Example: SHA-256 or SHA-512), the actual hexadecimal Public Key point which can be found in the Public Key xml file downloaded from the GSC web portal.
  • Page 55 ZED-F9T - Integration manual Trusted time messages Description UBX-MGA-INI-TIME_UTC These messages can be used to provide trusted time either in UTC or GNSS time, respectively. Both messages allow to provide a trusted flag UBX-MGA-INI_TIME_GNSS to the time. Table 25: Trusted time messages To protect the integrity of the trusted time provided by the host, it is propagated by the receiver using an internal free-running TCXO.

  • Page 56: U-Blox Protocol Feature Descriptions

    I/NAV message of the E1B signal, only UTC(EU) and UTC(USNO) can be authenticated. Table 28: OSNMA verification messages 3.12 u-blox protocol feature descriptions 3.12.1 Broadcast navigation data This section describes the data reported via UBX-RXM-SFRBX. UBX-RXM-SFRBX reports the broadcast navigation data message the receiver has collected from each tracked signal.
  • Page 57 ZED-F9T - Integration manual In most cases, the data does not map perfectly into a number of 32-bit words and, consequently, some of the words reported in UBX-RXM-SFRBX messages contain fields marked as "Pad". These fields should be ignored and no assumption should be made about their contents. UBX-RXM-SFRBX messages are only generated when complete subframes are detected by the receiver and all appropriate parity checks have passed.
  • Page 58 ZED-F9T - Integration manual Figure 22: GPS L2C subframe words 3.12.1.2.3 GPS L5 For GPS L5 signals each reported subframe contains the CNAV message as described in the GPS ICD. The ten words are arranged as follows: UBX-21040375 - R02 3 Receiver functionality Page 58 of 100  ...
  • Page 59 ZED-F9T - Integration manual Figure 23: GPS L5 subframe words 3.12.1.3 GLONASS For GLONASS L1OF signal, the UBX-RXM-SFRBX message contains a string content within the frame structure as described in the GLONASS ICD. This string comprises 85 data bits which are reported over three 32-bit words in the message. Data bits 1 to 8 are always a hamming code, while bits 81 to 84 are a string number and bit 85 is the idle chip, which should always have a value of zero.
  • Page 60 ZED-F9T - Integration manual Figure 24: GLONASS navigation message data In some circumstances, (especially on startup) the receiver may be able to decode data from a GLONASS satellite before it can identify it. When this occurs UBX-RXM-SFRBX messages will be issued with an svId of 255 to indicate "unknown". 3.12.1.4 BeiDou For BeiDou signals there is a fairly straightforward mapping between the reported subframe and the structure of subframe and words described in the BeiDou ICD.
  • Page 61 ZED-F9T - Integration manual 3.12.1.5.1 Galileo E1-B For the Galileo E1-B signal, each reported subframe contains a pair of I/NAV pages as described in the Galileo ICD. Galileo pages can either be "Nominal" or "Alert" pages. For Galileo "Nominal" pages the eight words are arranged as follows: Figure 26: Galileo E1-B subframe words UBX-21040375 - R02 3 Receiver functionality...
  • Page 62 ZED-F9T - Integration manual Alert pages are reported in very similar manner, but the page type bits will have value 1 and the structure of the eight words will be slightly different (as indicated by the Galileo ICD). 3.12.1.5.2 Galileo E5b For the Galileo E5b in-phase signal data component, each reported subframe contains a pair of I/ NAV pages as described in the Galileo ICD.
  • Page 63 ZED-F9T - Integration manual 3.12.1.5.3 Galileo E5a For the Galileo E5a in-phase signal data component, each reported subframe contains a number of F/NAV pages as described in the Galileo ICD. For each page the eight words are arranged as follows: Figure 28: Galileo E5a subframe words 3.12.1.6 SBAS For SBAS (L1C/A) signals each reported subframe contains eight 32-bit data words to deliver the 250 bits transmitted in each SBAS data block.
  • Page 64 ZED-F9T - Integration manual Figure 29: SBAS subframe words 3.12.1.7 QZSS The structure of the data delivered by QZSS L1C/A signals is effectively identical to that of GPS (L1C/A). Similarly the structure of the data delivered by the QZSS L2C signal is effectively identical to that of GPS (L2C).

  • Page 65: Save-On-Shutdown Feature

    • The host commands the saving of the contents of BBR to the flash memory using the UBX- UPD-SOS-BACKUP message. • For a valid request the u-blox receiver reports on the success of the backup operation with a UBX-UPD-SOS-ACK message.

  • Page 66: Sky View Signal Masking

    ZED-F9T - Integration manual The message is output once per second when enabled. Depending on the receiver type, one or two measurement blocks will be output, indicated by the numRfBlocks flag field. The first block provides L1 spectrum data which can be followed by an L2 or L5 block with multi-band receivers. Each block comprises the following data: •...

  • Page 67: Forcing A Receiver Reset

    ZED-F9T - Integration manual for timing receivers when surveyed into urban locations with a restricted sky view. Customers can e.g. use local mapping data to predict the sky view and set appropriate masking parameters. The CFG-NAVMASK-EL_MASK configuration allows masking of set parts of the sky in increments of nominally 5 deg.

  • Page 68: Firmware Upload

    Contact u-blox for more information on firmware update. 3.15 Production test u-blox focuses on high quality for its products. To achieve this, we only supply fully tested units. At the end of the production process, every unit is tested. Defective units are analyzed in detail to continuously improve the production quality.

  • Page 69: Design

    ZED-F9T - Integration manual 4 Design This section provides information to help carry out a successful schematic and PCB design integrating the ZED-F9T. Do not load Pin 4 (ANT_DETECT) with a capacitance more than 1 nF. 4.1 Pin assignment The pin assignment of the ZED-F9T module is shown in Figure 31.
  • Page 70 ZED-F9T - Integration manual Pin no. Name Description VCC_RF Voltage for external LNA Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Ground Reserved Reserved Ground Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved GEOFENCE_STAT Geofence status, user defined Reserved Reserved Reserved Reserved Reserved Reserved Reserved...

  • Page 71: Power Supply

    The module integrates a DC/DC converter, which allows reduced power consumption. When switching from backup mode to normal operation or at startup, u-blox ZED-F9T modules must charge the internal capacitors in the core domain. In certain situations, this can result in a significant current draw.

  • Page 72: Zed-F9T Power Supply

    ZED-F9T - Integration manual Add a 2 uF capacitor on the V_BCKP pin to absorb the current adjustment peak when switching from VCC to V_BCKP supply. If no backup supply voltage is available, connect the V_BCKP pin to VCC. Allow all I/O including UART and other interfaces to float or connect to a high impedance in HW backup mode (V_BCKP supplied when VCC is removed).

  • Page 73: Antenna

    Implementing a custom active antenna design is an important exercise to meet the required bandwidths and group delay specifications compared to previous L1-only designs. A typical dual band antenna design block diagram is shown below taken from the u-blox ANN-MB active antenna product. UBX-21040375 - R02...
  • Page 74 ZED-F9T - Integration manual Figure 34: u-blox low cost dual-band antenna internal structure A suitable ground plane is required for the antenna to achieve good performance. Location of the antenna is critical to reach the stated performance. For timing receivers locate to provide a good all round sky view. Unsuitable locations within a vehicle could include, under vehicle dash, rear-view mirror location, etc.

  • Page 75: Active Antenna Power Supply

    ZED-F9T - Integration manual The antenna system should include filtering to ensure adequate protection from nearby transmitters. Take care in the selection of antennas placed close to cellular or Wi-Fi transmitting antennas. 4.4.1 Active Antenna Power Supply The antenna power supply is typically used to power GNSS active antennas. The power supply should be able to provide the correct voltage and current to the antenna to ensure optimal performance of ZED-F9T.
  • Page 76 ZED-F9T - Integration manual Figure 36: ZED-F9T with external voltage antenna bias Part Specifications Values Filtering capacitor 100 nF, 16 V Ferrite bead BLM15HB121SH1 Minimum Current of 300 mA or more impedance >500 LQG15HS47NJ02 Ω at GNSS frequencies Current limit resistor 10 Ω Table 32: ZED-F9T external voltage antenna bias components 4.4.1.2 External power supply and current limiting Figure 37...
  • Page 77 ZED-F9T - Integration manual Figure 37: ZED-F9T with external voltage antenna bias and current limit circuit Part Specifications Values Filtering capacitor 10n, Bias-T, X7R 10N 10% 16 V Filtering capacitor 100 nF, 16 V Ferrite bead BLM15HB121SH1 Minimum Current of 300 mA or more impedance >500 LQG15HS47NJ02 Ω...

  • Page 78: Antenna Supervisor Circuit

    ZED-F9T - Integration manual Figure 38: ZED-F9T VCC_RF antenna bias Part Specifications Values Filtering capacitor 100 nF, 16 V Ferrite bead BLM15HB121SH1 Minimum Current of 300 mA or more impedance >500 LQG15HS47NJ02 Ω at GNSS frequencies Current limit resistor 10 Ω Table 34: ZED-F9T VCC_RF antenna bias components 4.4.2 Antenna supervisor circuit The active antenna supervisor circuit connects to three ZED-F9T pins: •...
  • Page 79 ZED-F9T - Integration manual Figure 39: ZED-F9T antenna supervisor circuit The bias-T inductor L4 should support multi-band operation within the 1–1.8 GHz frequency range. For additional information, see Active Antenna Power Supply section. Part Specifications Filtering capacitor Minimum Current of 300 mA or more. Impedance >500 Ω at GNSS frequencies Passive pull-up to control T5 Current limiter in the event of a short circuit Defines the threshold of the comparator...

  • Page 80: Eos/Esd Precautions

    ZED-F9T - Integration manual 4.5 EOS/ESD precautions To avoid overstress damage during production or in the field it is essential to observe strict EOS/ ESD/EMI handling and protection measures. To prevent overstress damage at the RF_IN of your receiver, never exceed the maximum input power as specified in the applicable Data sheet [1].

  • Page 81: Safety Precautions

    ZED-F9T - Integration manual Figure 41: Active antenna EOS protection 4.5.3 Safety precautions The ZED-F9T must be supplied by an external limited power source in compliance with the clause 2.5 of the standard IEC 60950-1. In addition to external limited power source, only Separated or Safety Extra-Low Voltage (SELV) circuits are to be connected to the module including interfaces and antennas.

  • Page 82: In-Band Interference Mitigation

    ZED-F9T - Integration manual • In-band interference: Although the GNSS band is kept free from intentional RF signal sources by radio-communications standards, many devices emit RF power into the GNSS band at levels much higher than the GNSS signal itself. One reason is that the frequency band above 1 GHz is not well regulated with regards to EMI, and even if permitted, signal levels are much higher than GNSS signal power.

  • Page 83: Layout

    ZED-F9T - Integration manual 4.7 Layout This section details layout and placement requirements of the ZED-F9T high accuracy timing receiver. 4.7.1 Placement GNSS signals at the surface of the Earth are below the thermal noise floor. A very important factor in achieving maximum GNSS performance is the placement of the receiver on the PCB. The placement used may affect RF signal loss from antenna to receiver input and enable interference into the sensitive parts of the receiver chain, including the antenna itself.
  • Page 84 ZED-F9T - Integration manual 4.7.3.1 Footprint Figure 42: ZED-F9T suggested footprint (i.e. copper mask) Symbol Dimension (mm) Symbol Dimension (mm) 23.00 17.40 1.50 0.80 1.10 2.10 1.10 1.05 0.55 9.95 7.45 0.85 2.80 0.20 1.35 1.20 0.30 Table 36: ZED-F9T footprint dimensions UBX-21040375 - R02 4 Design Page 84 of 100...

  • Page 85: Layout Guidance

    ZED-F9T - Integration manual 4.7.3.2 Paste mask Figure 43: ZED-F9T suggested paste mask Symbol Dimension (mm) Symbol Dimension (mm) 1.55 0.75 1.05 2.10 1.10 1.05 0.55 10.00 7.50 0.90 2.85 0.20 1.35 Table 37: ZED-F9T paste mask dimensions 4.7.4 Layout guidance The presented layout guidance reduces the risk of performance issues at design level. 4.7.4.1 RF In trace The RF in trace has to work in the combined GNSS signal bands.
  • Page 86 ZED-F9T - Integration manual A grounded co-planar RF trace is recommended as it provides the maximum shielding from noise with adequate vias to the ground layer. The RF trace must be shielded by vias to ground along the entire length of the trace and the ZED- F9T RF_IN pad should be surrounded by vias as shown in the figure below.

  • Page 87: Design Guidance

    ZED-F9T - Integration manual pad and the de-coupling capacitors must be placed as close as possible. This is shown in the figure below. Figure 46: VCC pads 4.8 Design guidance 4.8.1 General considerations Do not load Pin 4 (ANT_DETECT) with a capacitance more than 1 nF. Check power supply requirements and schematic: •...

  • Page 88: Antenna/Rf Input

    ZED-F9T - Integration manual The first stages of the signal processing chain are crucial to the overall receiver performance. When an RF input connector is employed this can provide a conduction path for harmful or destructive electrical signals. If this is a likely factor the RF input should be protected accordingly. Additional points on the RF input •...

  • Page 89: Ground Pads

    I2C lines to the supply rails to pull the line high when it’s not driven low by the open-drain interface. The u-blox chip integrates internal pull-up resistors at the SCL and SDA pins. These resistors have a large value variation (chip to chip, over temperature, voltage), see product datasheet. To minimize timing variations, it is suggested adding external pull-up resistors with lower resistance at the SCL and SDA pins in parallel to the internal ones.

  • Page 90: Emi/Emc Considerations For I2C Bus

    ZED-F9T - Integration manual Figure 47: I2C bus signal rise and fall time The minimum pull up R resistance is based on the bus voltage (V ), the maximum voltage that p(min) can be read as a logic-low (V ), and the maximum current that the pins can sink when at or below = (V –...

  • Page 91: Product Handling

    5 Product handling 5.1 ESD handling precautions CAUTION! Risk of electrostatic discharge (ESD) damage. u-blox chips and modules are electrostatic sensitive devices containing highly sensitive electronic circuitry. A discharge of static electricity may damage the device or reduce the life expectancy of the device. To avoid ESD damage, adhere to the standard guidelines for handling ESD devices.

  • Page 92: Soldering

    ZED-F9T - Integration manual Figure 48: Standard workstation setup for safe handling of ESD-sensitive devices 5.2 Soldering Soldering paste Use of “no clean” soldering paste is highly recommended, as it does not require cleaning after the soldering process. For instance, the paste in the example below meets these criteria. •...
  • Page 93 ZED-F9T - Integration manual For the recommended soldering profile and conditions, see Figure 49, and Table 38 Figure 49: Recommended soldering profile for professional grade ZED-F9T Phase Value Details Preheating During the initial heating of component leads and balls, residual humidity is dried out. Note that the preheating phase does not replace prior baking procedures.
  • Page 94 ZED-F9T - Integration manual Phase Value Details Max 4 °C/s Temperature fall rate Table 38: Recommended conditions for reflow soldering Optical inspection After soldering the module, consider optical inspection. Cleaning Do not clean with water, solvent, or ultrasonic cleaner: • Cleaning with water will lead to capillary effects where water is absorbed into the gap between the baseboard and the module.

  • Page 95: Tapes

    EMI covers is done at the customer’s own risk. The numerous ground pins should be sufficient to provide optimum immunity to interference and noise. u-blox provides no warranty for damages to the module caused by soldering metal cables or any other forms of metal strips directly onto the EMI covers.

  • Page 96: Reels

    ZED-F9T - Integration manual Figure 51: ZED-F9T tape dimensions (mm) 5.4 Reels The ZED-F9T receivers are deliverable in quantities of 250 pieces on a reel. The receivers are shipped on reel type B, as specified in the Product packaging reference guide [3]. UBX-21040375 - R02 5 Product handling Page 96 of 100...

  • Page 97: Appendix

    Printed circuit board QZSS Quasi-Zenith Satellite System Radio frequency RTCM Radio Technical Commission for Maritime Services SBAS Satellite-based Augmentation System Space vehicle, a satellite TDOP Time dilution of precision u-blox UBX-21040375 - R02 Appendix Page 97 of 100   C1-Public...

  • Page 98: Related Documents

    TIM 2.20 Interface description, UBX-21048598 TIM 2.24 Interface description, UBXDOC-963802114-13046 Product packaging reference guide, UBX-14001652 For regular updates to u-blox documentation and to receive product change notifications please register on our homepage https://www.u-blox.com. UBX-21040375 - R02 Related documents Page 98 of 100  ...

  • Page 99: Revision History

    ZED-F9T - Integration manual Revision history Revision Date Status / comments 11-Jan-2022 Combined Integration Manual issued for ZED-F9T-00B and 10B variants, 3.1.2 NavIC capability included, 3.5.1 baud rate change delay warning, 3.6.4 warning added for time pulse 2-pin usage, 3.8 MGA sec. reduced - interface operation transferred to Services documentation, 3.8.2 data base dump added, 3.9.4 NavIC time base added, 3.10.3 Time Mark message for CVTT added, 3.11.3 security message usage added, 3.12.4 Satellite masking message added.
  • Page 100 ZED-F9T - Integration manual Contact u-blox AG Address: Zürcherstrasse 68 8800 Thalwil Switzerland For further support and contact information, visit us at www.u-blox.com/support. UBX-21040375 - R02 Page 100 of 100   C1-Public...

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