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SL876Q5-A   

Product User Guide 

1VV0301333 Rev. 2

 

Page 48 of 68 

2017-06-27  

general direction, the geometry of the remaining satellites will result is a lower position 
accuracy. The receiver reports this geometry effect in the form of PDOP, HDOP and VDOP 
numbers. 

For example, in a vehicular application, the GNSS antenna may be placed on the dashboard 
or rear package tray of an automobile. The metal roof of the vehicle will cause significant 
blockage, plus any thermal coating applied to the vehicle glass can attenuate the GNSS signal 
by as much as 15 dB. Again, both of these factors will affect the performance of the receiver. 

Multipath interference is a phenomena where the signal from a particular satellite is reflected 
and is received by the GNSS antenna in addition to or in place of the line of sight signal. The 
reflected signal has a path length that is longer than the line of sight path and can either 
attenuate the original signal, or, if received in place of the original signal, can add error in 
determining a solution because the distance to the particular satellite is actually shorter than 
measured. It is this phenomenon that makes GNSS navigation in urban canyons (narrow roads 
surrounded by high rise buildings) so challenging. In general, the reflection of a GNSS signal 
causes the polarization to reverse. The implications of this are covered in the next section. 

 

GNSS Antenna Polarization 

The GPS broadcast signal is Right Hand Circularly Polarized (RHCP).  

An RHCP antenna will have 3 dB gain compared to a linearly-polarized antenna (assuming the 
same antenna gain specified in dBic and dBi respectively). 

An RHCP antenna is better at rejecting multipath interference than a linearly polarized antenna 
because the reflected signal changes polarization to LHCP. This signal would be rejected by 
the RHCP antenna, typically by 20 dB or greater.  

If the multipath signal is attenuating the line of sight signal, then the RHCP antenna would 
show a higher signal level than a linearly polarized antenna because the interfering signal is 
rejected. 

However, in the case where the multipath signal is replacing the line of sight signal, such as in 
an urban canyon environment, then the number of satellites in view could drop below the 
minimum needed to determine a 3D position. This is a case where a bad signal may be better 
than no signal. The system designer needs to understand trade-offs in their application to 
determine the better choice. 

 

 

Active versus Passive Antenna 

If the GNSS antenna is placed near the receiver and the RF trace losses are not excessive 
(nominally 1 dB), then a passive antenna may be used. This would often be the lowest cost 
option and most of the time the simplest to use. However, if the antenna needs to be located 
away from the receiver, then an active antenna may be required to obtain the best system 
performance. An active antenna includes a built- in low noise amplifier (LNA) to overcome RF 
trace and cable losses. Also, many active antennas have a pre-select filter, a post-select filter, 
or both. 

Important specifications for an active antenna LNA are gain and noise figure.  

 

 

Содержание SL876Q5-A

Страница 1: ...SL876Q5 A Product User Guide 1VV0301333 Rev 2 2017 06 27...

Страница 2: ...for copyrighted material including the exclusive right to copy reproduce in any form distribute and make derivative works of the copyrighted material Accordingly any copyrighted material of Telit and...

Страница 3: ...vities IV Trademarks TELIT and the Stylized T Logo are registered in Trademark Office All other product or service names are the property of their respective owners V Third Party Rights The software m...

Страница 4: ...SL876Q5 A Product User Guide 1VV0301333 Rev 2 Page 4 of 68 2017 06 27 PRODUCT APPLICABILITY TABLE Product SE876Q5 A...

Страница 5: ...iagram 15 SL876Q5 A Module 16 3 SL876Q5 A EVALUATION KIT EVK 17 SL876Q5 A Evaluation Board EVB 18 4 PRODUCT FEATURES 19 Built in Antenna and Switch 19 Multi Constellation Navigation 19 Quasi Zenith Sa...

Страница 6: ...ty 27 6 SOFTWARE INTERFACE 28 NMEA Output Messages 28 Standard Messages 28 SiRF Proprietary Messages 29 Telit Proprietary Messages 29 NMEA Input Commands 30 Change output sentences and their rates 30...

Страница 7: ...41 Frequency Plan 41 Local Oscillator Leakage 41 Host I O Ports Configuration and Operation 42 Primary Host Port Configuration 42 Secondary Host Port Configuration 42 UART Operation 42 I2 C Operation...

Страница 8: ...ivity 58 ESD Sensitivity 59 Reflow 59 Assembly Considerations 59 Washing Considerations 59 Safety 59 Disposal 59 14 ENVIRONMENTAL REQUIREMENTS 60 Operating Environmental Limits 60 Storage Environmenta...

Страница 9: ...76Q5 A Evaluation Board 18 Figure 8 1 SL876Q5 A Pin out Diagram 32 Figure 9 1 Reference Design 45 Figure 10 1 RF Trace Examples 50 Figure 11 1 SL876Q5 A Mechanical Drawing 53 Figure 12 1 SL876Q5 A Foo...

Страница 10: ...ble 8 2 DC Characteristics 35 Table 8 3 Absolute Maximum Ratings 35 Table 8 4 DC Supply Voltage 36 Table 8 5 Power Consumption SL876Q5 A 37 Table 8 6 Power Consumption SL876Q5 A Low Power modes 37 Tab...

Страница 11: ...ort documentation errors contact Telit Technical Support at TS EMEA telit com TS AMERICAS telit com TS APAC telit com Alternatively use http www telit com support For detailed information about where...

Страница 12: ...ger This information MUST be followed or catastrophic equipment failure and or bodily injury may occur Caution or Warning This is an important point about integrating the product into a system If this...

Страница 13: ...eet SL876Q5 A Evaluation Kit User Guide Related Documents Requiring a Non disclosure Agreement SiRFstarV B02 Designer s Guide SiRFstarV B02 Software User s Guide NMEA Reference Guide CS 129435 MA8 SiR...

Страница 14: ...1 simultaneous ranging Galileo ready SBAS capable WAAS EGNOS MSAS GAGAN including ranging AGPS support for extended ephemeris using local or server based solutions o Client Generated Extended Ephemeri...

Страница 15: ...SL876Q5 A Product User Guide 1VV0301333 Rev 2 Page 15 of 68 2017 06 27 SL876Q5 A Block Diagram Figure 2 1 SL876Q5 A Block Diagram...

Страница 16: ...SL876Q5 A Product User Guide 1VV0301333 Rev 2 Page 16 of 68 2017 06 27 SL876Q5 A Module Figure 2 2 SL876Q5 A module photo...

Страница 17: ...SL876Q5 A Product User Guide 1VV0301333 Rev 2 Page 17 of 68 2017 06 27 3 SL876Q5 A EVALUATION KIT EVK Figure 3 1 Evaluation Kit EVK contents...

Страница 18: ...SL876Q5 A Product User Guide 1VV0301333 Rev 2 Page 18 of 68 2017 06 27 SL876Q5 A Evaluation Board EVB Figure 3 2 SL876Q5 A Evaluation Board...

Страница 19: ...ms WAAS EGNOS GAGAN and MSAS use geostationary satellites to transmit regional corrections via a GNSS compatible signal SBAS Corrections The SBAS satellites transmit a set of differential corrections...

Страница 20: ...by default Server generated Extended Ephemeris SGEE Extended ephemeris is computed at the server and saved in a file which can then be downloaded to the receiver s flash memory The server file contain...

Страница 21: ...any operator intervention GPS GLONASS and BDS band cancellers are activated and reported using OSP Message ID 92 This feature is useful both in the design stage and during the production stage for unc...

Страница 22: ...is commanded the output report rate is 10 Hz 1PPS The module provides a 1PPS timing pulse output See Section 8 6 1 1PPS for details I O Communication Ports The 1st host port can be configured to commu...

Страница 23: ...operation in reporting position fixes optimized for the best all around performance SmartGNSS modes save power based on satellite signal strength SiRFSmartGNSS 1 SiRFSmartGNSS 2 Periodic Fixes Trickle...

Страница 24: ...a fixed rate of 1 to 10 seconds and retains good accuracy and dynamic motion response but at a lower average power consumption than Full Power The receiver will go to FULL POWER if signals are weak o...

Страница 25: ...ce the receiver is not operating until after wake up See section 8 8 1 Primary Host Port Configuration for configurationdetails MEMS Wakeup 2nd Port I2C If the 2nd port is operating as I2C the module...

Страница 26: ...iDou 2 5 Test Conditions 24 hr Static 130 dBm Full Power mode Table 5 1 SL876Q5 A Horizontal Position Accuracy Time to First Fix Constellations s Start Type Max TTFF s GPS Hot 1 1 Warm Assisted 7 5 Wa...

Страница 27: ...017 06 27 Sensitivity Constellation s State Minimum Signal Level dBm External Ant GPS Acquisition 148 Navigation 161 Tracking 165 GPS GLO Acquisition 148 Navigation 161 Tracking 165 Test conditions St...

Страница 28: ...ndard Messages These messages are sent by default Message ID Description Frequency RMC GNSS Recommended minimum navigation data 1 GGA GNSS position fix data 1 GSA GNSS Dilution of Precision DOP and ac...

Страница 29: ...proprietary NMEA output messages PSRF which report additional receiver data and status information Some of these messages exceed the 80 character limitation of the NMEA 0183 standard Telit Proprietar...

Страница 30: ...ery Rate Control PSRF103 command to enable and disable output NMEA messages and set their output rates Change data rate Use the Set Serial Port PSRF100 command to change the port data rate Switch to O...

Страница 31: ...v 2 Page 31 of 68 2017 06 27 7 FLASH UPGRADABILITY The firmware stored in the internal Flash memory of the SL876Q5 A may be upgraded via the serial port TX RX pads Please refer to the SL876Q5 A Evalua...

Страница 32: ...SL876Q5 A Product User Guide 1VV0301333 Rev 2 Page 32 of 68 2017 06 27 8 ELECTRICAL INTERFACE Module Pin out Figure 8 1 SL876Q5 A Pin out Diagram...

Страница 33: ...read prior to the host select lines GPIO 6 7 This pin should be brought out to a test point or left floating See Section 7 Flash Upgradability 16 GPIO6 I GPIOs 6 7 are read during power up and reset t...

Страница 34: ...O or SPI Data In MOSI 16 GPIO6 I O After configuration may be used for UART nCTS or SPI CLK 6 GPIO7 I O After configuration may be used for UART nRTS or SPI nCS 23 GPIOA I2 C Data Ready Indicator Seco...

Страница 35: ...50 86 157 k RPD Internal pull down resistor equivalent 51 91 180 k LI Input leakage at VI 1 8 V or 0 V 10 10 A LO Tristate output leakage at VO 1 8 V or 0 V 10 10 A CI Input capacitance digital output...

Страница 36: ...mory from accidental writes during a power down condition This reset forces the module into a low power stand by state To prevent the reset the 1 8 volt supply must be regulated to be within 50 mV of...

Страница 37: ...d Glonass 84 89 mW Navigation Tracking GPS Only 53 67 mW GPS and Glonass 70 80 mW Table 8 5 Power Consumption SL876Q5 A Low Power Modes Low Power Mode Typ Units Trickle Power 15 mW Push to Fix 17 mW B...

Страница 38: ...nd STANDBY via TricklePower modes and between RUN and HIBERNATE via PushToFixII and SiRFaware modes It can also transition from RUN to HIBERNATE by de asserting the ON OFF signal The firmware is confi...

Страница 39: ...a the default RF input See Section 8 6 3 LNA Enable Control Output Signals 1PPS 1PPS is a one pulse per second signal which is enabled after the receiver has achieved a 5 satellite Kalman filter posit...

Страница 40: ...noise figure of less than 1 0 dB should be used for optimum results The SL876Q5 A contains an internal pre select SAW filter which is in both the External and Internal antenna input paths The chipset...

Страница 41: ...solving narrow band CW EMI problems in the customer s system It is effective against narrow band clock harmonics Jamming Rejection is not effective against wide band noise e g from a host CPU memory b...

Страница 42: ...Pullup 10 k to 1 8 V may become CTS Float Float becomes SCLK GPIO7 Weak internal pullup Float may become RTS Pulldown 10 k to ground Float becomes SPI_CS Table 8 10 Primary Host I O Port Configuratio...

Страница 43: ...ol on the first port I2C Operation See Section 8 8 1 Primary Host Port Configuration to specify I2 C interface Upon power up the module acts as a master transmitter and a slave receiver multi master m...

Страница 44: ...nts SPI Operation See Section 8 8 1 Primary Host Port Configuration to specify SPI interface The 2nd port cannot be configured for SPI interface since there are only two pins available SPI is supporte...

Страница 45: ...SL876Q5 A Product User Guide 1VV0301333 Rev 2 Page 45 of 68 2017 06 27 9 REFERENCE DESIGN Figure 9 1 Reference Design...

Страница 46: ...at that RF frequency The internal chip antenna is enabled by grounding the INT nEXT_Ant_En pin through JP3 The TX RX serial port can be configured for UART I2 C or SPI interface using GPIO 6 and 7 As...

Страница 47: ...arly polarized antenna is not less than 131dBm for L1 sub band provided that the satellite is observed at an angle 5 degrees or more above the horizon The receiver will display a reported C No of 40 d...

Страница 48: ...y Polarized RHCP An RHCP antenna will have 3 dB gain compared to a linearly polarized antenna assuming the same antenna gain specified in dBic and dBi respectively An RHCP antenna is better at rejecti...

Страница 49: ...5 dBic at azimuth and an LNA gain of 20 dB for a combined total of 25 dB Antenna Y has an antenna gain of 5 dBic at azimuth and an LNA gain of 30 dB for a combined total of 25 dB However in the syste...

Страница 50: ...ects of component pads that are in the path of the 50 trace If the traces are shorter than a 1 16th wavelength transmission line effects will be minimized but stray capacitance from large component pa...

Страница 51: ...erence RF interference into the GNSS receiver tends to be the biggest problem when determining why the system performance is not meeting expectations As mentioned earlier the GNSS signals are at 130 d...

Страница 52: ...uarter wave stub in place of the inductor The length of the stub is designed to be exactly wavelength at L1 which has the effect of making an RF short at one end of the stub to appear as an RF open at...

Страница 53: ...SL876Q5 A Product User Guide 1VV0301333 Rev 2 Page 53 of 68 2017 06 27 11 MECHANICAL DRAWING Figure 11 1 SL876Q5 A Mechanical Drawing...

Страница 54: ...uires a reference ground plane of 40mm by 80mm for the chip antenna to work properly The SL876 A is centered on the long axis but flush with the top edge of the reference ground plane shown to the lef...

Страница 55: ...erly The SL876 A is centered on the long axis but flush with the top edge of the reference ground plane shown to the left here This drawing identifies the dimensions for the user s PCB for the SL876 A...

Страница 56: ...ule serial number Contact a Telit representative for information on specific module serial numbers Product Label SL876Q5 A Figure 13 1 SL876Q5 A Product Label Key Description 0 Pin 1 location 1 Telit...

Страница 57: ...Q5 A Product User Guide 1VV0301333 Rev 2 Page 57 of 68 2017 06 27 Product Packaging SL876Q5 A modules are supplied in Tray packaging of 90 pcs as shown below Figure 13 2 Product Packaging Tray 90 pcs...

Страница 58: ...card The SL876Q5 A parts must be placed and reflowed within 168 hours of first opening the hermetic seal provided the factory conditions are less than 30 C and less than 60 and the humidity indicator...

Страница 59: ...liquidus temperature while the module is inverted Note JEDEC standards are available free from the JEDEC website http www jedec org Assembly Considerations During board assembly and singulation proce...

Страница 60: ...0 m Software ITAR restriction Maximum Vehicle Dynamics 514 m s acquisition and navigation 2 G acceleration Software ITAR restriction Table 14 1 Operating Environmental Limits Storage Environmental Lim...

Страница 61: ...ity Certificate in process RoHS Certificate The Telit SL876Q5 A modules are fully compliant with the EU RoHS Directives Directive 2002 95 EC on the restriction of the use of certain hazardous substanc...

Страница 62: ...satellite signals and calculate a navigation solution from a Cold Start Cold start acquisition sensitivity is limited by the data decoding threshold of the satellite messages EGNOS European Geostation...

Страница 63: ...ion Sensitivity The lowest signal level at which a GNSS receiver is able to reliably maintain navigation after the satellite signals have been acquired NMEA National Marine Electronics Association QZS...

Страница 64: ...iver is able to maintain tracking of a satellite signal after acquisition is complete TTFF Time to First Fix The elapsed time required by a receiver to achieve a valid position solution from a specifi...

Страница 65: ...e equipped with a proper antenna with specific characteristics The European Community provides directives for electronic equipment introduced in the market Relevant information is available on the Eur...

Страница 66: ...device must be supplied with a limited power source that meets clause 2 5 of the EN 60950 1 standard These requirements are For power supplies without overcurrent protection device Short circuit curr...

Страница 67: ...V0301333 Rev 2 Page 67 of 68 2017 06 27 18 DOCUMENT HISTORY Revision Date Changes 0 2017 03 02 Initial issue 1 2017 06 21 Added ground plane information Minor text revisions and additions 2 2017 06 27...

Страница 68: ......

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