GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 1 INTRODUCTION GNS902 is a small autonomous GPS/GLONASS receiver, based on the MediaTek MT3333 single chip, with a finely tuned, high-sensitivity ceramic chip antenna. The receiver supports GPS and GLONASS simultaneously. The navigation performance and accuracy is further improved by using correction data from SBAS (WAAS, EGNOS, GAGAN, MSAS), QZSS. First Fixes after just a few seconds are achieved with the help of A-GPS using EPOTM (Extended Prediction Orbit) and the EASYTM "self generated orbit prediction" algorithm. EASYTM (Embedded Assist System) does not require any resources or assist data from the host. The excellent low power design makes it easy to implement this receiver in power sensitive, battery supplied applications. The new AlwaysLocateTM power management feature will improve this behaviour additionally. It adaptively adjusts power consumption depending on the environment and motion conditions, in order to achive a balance between fix rate, power consumption and position accuracy. Very low power requirements (typ 70mW@3.3V, tracking for GPS+GLONASS) and internal voltage regulator makes it easy to run the receiver with various power supplies and allows direct connection to LiIon batteries. GNS902 offers the industry's highest level of navigation sensitivity up to -165dBm1. It has superior dynamic performance at high velocity and provides effective protection against interference signals (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 1 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification TM using MTAIC ( Multi-tone active interference canceller). Up to 12 independent channel interference continious wave jammers <-80dBm can be eliminated or reduced. The embedded logger function LOCUS with a 16-hrs on chip memory makes this GNSS module a complete track logger for many applications. In professional timing applications the outstanding high accuracy PPS (pulse per second) hardware pin is used for synchronization to GPS second. Typical accuracy is 10ns RMS. Note: This module is designed to be operated on a mainboard, that provides a minimum of 20mm x 30mm ground plane. Sensitivity will be decreased if no groundplane is provided. Features * * * * * * * * * * * * * * * * * * 1 GLONASS and GPS simultaneously 99 acquisition-/ 33 tracking channels Ultra high tracking/navigation sensitivity: -165dBm1 smart antenna: tuned miniature ceramic chip antenna SBAS (WAAS,EGNOS,MSAS,GAGAN, QZSS) correction support A-GPS by EPO "Extended Prediction Orbit" TM enables 7/14days prediction 12 Multitone Active Interference Canceller (MTAIC) for GPS-in-band jammer rejection EASY TM : Self generated orbit prediction support AlwaysLocate TM : Intelligent Algorithm for power saving High accuracy 1PPS output NMEA-0183 or binary protocol High update rate (up to 10/s) Embedded logger function with 16hrs internal memory GNSS current consumption (@3.3V): Acquisition: 28mA Typical Tracking: 22mA Typical Low backup current consumption 15uA, typical SMD type Small form factor: 15.7x10x2.0mm CE, FCC and RohS certified Note: Measured navigation sensitivity at RF input of chipset (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 2 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 2 INDEX 1 INTRODUCTION ----------------------------------------------------------------------------------------- 1 2 INDEX --------------------------------------------------------------------------------------------------- 3 3 FUNCTIONAL DESCRIPTION ---------------------------------------------------------------------------- 4 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 System description ---------------------------------------------------------------------------------------------------------4 Block diagram --------------------------------------------------------------------------------------------------------------4 GPS and GLONASS simultaneous operation ------------------------------------------------------------------------------5 Power Management Features ----------------------------------------------------------------------------------------------5 Logger function -------------------------------------------------------------------------------------------------------------7 Active interference cancellation (MTAIC) ---------------------------------------------------------------------------------7 AGPS with EPO data --------------------------------------------------------------------------------------------------------8 EASYTM self generated prediction data feature ----------------------------------------------------------------------------8 Pulse Per Second (PPS) ----------------------------------------------------------------------------------------------------9 SBAS (Satellite Based Augmentation) support ------------------------------------------------------------------------- 10 binary output ------------------------------------------------------------------------------------------------------------- 10 GPS/GLONASS almanac and ephemeris data--------------------------------------------------------------------------- 10 Real time clock (RTC) ---------------------------------------------------------------------------------------------------- 10 UART interface ------------------------------------------------------------------------------------------------------------ 10 Module default settings -------------------------------------------------------------------------------------------------- 11 4.1 Typical System Overview ------------------------------------------------------------------------------------------------ 12 5.1 GPS/GLONASS characteristics ------------------------------------------------------------------------------------------- 13 6.1 6.2 Absolute Maximum Ratings ---------------------------------------------------------------------------------------------- 14 Recommended Operating Conditions ----------------------------------------------------------------------------------- 14 10.1 PCB LAYOUT GUIDELINES ----------------------------------------------------------------------------------------------- 19 4 TYPICAL APPLICATION BLOCK DIAGRAM ------------------------------------------------------------ 12 5 GPS/GLONASS characteristics ------------------------------------------------------------------------ 13 6 ELECTRICAL SPECIFICATION ------------------------------------------------------------------------- 14 7 PIN CONFIGURATION --------------------------------------------------------------------------------8 PHYSICAL DIMENSIONS -----------------------------------------------------------------------------9 RECOMMENDED PAD LAYOUT -----------------------------------------------------------------------10 DESIGN GUIDELINES -------------------------------------------------------------------------------- 15 17 18 19 11 NMEA DATA interface -------------------------------------------------------------------------------- 21 11.1 11.2 NMEA output sentences -------------------------------------------------------------------------------------------------- 21 NMEA command interface------------------------------------------------------------------------------------------------ 22 14.1 14.2 TAPE ----------------------------------------------------------------------------------------------------------------------- 24 REEL ----------------------------------------------------------------------------------------------------------------------- 25 12 MATERIAL INFORMATION --------------------------------------------------------------------------- 23 13 RECOMMENDED SOLDERING REFLOW PROFILE --------------------------------------------------- 23 14 PACKAGE INFORMATION ---------------------------------------------------------------------------- 24 15 16 17 18 19 ORDERING INFORMATION -------------------------------------------------------------------------ENVIRONMENTAL INFORMATION ------------------------------------------------------------------MOISTURE SENSITIVITY ---------------------------------------------------------------------------DOCUMENT REVISION HISTORY -------------------------------------------------------------------RELATED DOCUMENTS ------------------------------------------------------------------------------ (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 25 26 26 27 27 3 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 3 FUNCTIONAL DESCRIPTION 3.1 System description The GNS902 is a high performance, low power GPS/GLONASS receiver that includes an integrated RF frontend (SAW Filter + LNA) and a ceramic chip antenna. Due to high input sensitivity and low noise amplifier (LNA), it can work at weak GPS/GLONASS signals. GNS902 is a complete autonomous GPS/GLONASS receiver, including: - Full GPS/GLONASS processing, without any host processing requirements Standard NMEA message output A powerful NMEA command and control interface All clock sources integrated RF frontend integrates a low noise amplifier (LNA) and a SAW filter Rich additional features like geofencing, single sentence output, last position retention, magnetic variation, distance calculation Interface for UART, PPS output pin, Fix Status Indicator pin 3.2 Block diagram GPS/GLONASS chip antenna 19 RESET 2 WAKEUP 4 3D-Fix 11 1PPS SAW filter +Low Noise Amplifier 9 RXB 8 TXA GPS /GLONASS chip 7 RXA VCC 14 32.768kHz crystal VBACKUP 13 26MHz TCXO GND 1,5,6,15,16,20 (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 4 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 3.3 GPS and GLONASS simultaneous operation GNS902 supports tracking of the GPS and the GLONASS satellite system at one time. This feature enhances the overall performance significant. Increased availability of number of satellites Increased spatial distribution allows better geometrical conditions Reduced Horizontal (HDOP) and Vertical Dilution of Precision (VDOP) factors In GPS-only operation, a minimum of 3 SVs is needed to determine a 2D position fix solution. When using both systems, 5 SVs are needed to determine the four unknowns and one more SV to calculate the GPS/GLONASS time offset. Using a combined receiver, users have an access to potentially 48 or more satellites. This high number of satellites can overcome the typical problems of restricted visibility of the sky, such as in urban canyons or indoor scenarios. 3.4 Power Management Features Power management schemes implemented for any GPS system requires an optimally tuned performance for both accuracy of the position fixes and the average power consumed for best user experience. GNS902 architecture achieves these both aspects by providing flexibility and design choices for the system integration, based on wide range of use cases and by leveraging on the proven silicon methodologies. Also GNS902 provides position, velocity and time measurements without any host loading. This, coupled with the optional built-in power management options, reduces the overall system power budget. Selectable Power management features: In Standby mode RF frontend and internal MPU are switched to deep sleep state. Power consumption is reduced.This state can be entered by sending the NMEA command: $PMTK161,0*28<CR><LF>. Leaving standby mode and resuming to normal operation will be managed by sending any byte to the module. (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 5 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification Backup mode can be entered by sending NMEA command: $PMTK225,4*2F<CR><LF>. The GPS core will shut down autonomously to backup state, Vcc supply can now be switched off by an external power supply switch. Periodic mode describes a power mode, which will autonomously power on/off the module in programmable time slots with reduced fix rate. Periodic mode is useful during stationary operation or if position fixes are just needed from time to time. Since power consumption in GPS off times is nearly zero, the power consumption in periodic mode can be estimated by Ptracking * (ton/(ton+toff)). Periodic mode is controlled with NMEA command $PTMK225. See document NMEA_Interface_manual_MTK_Vx for programming details. AlwaysLocateTM feature provides an optimized overall GPS/GLONASS system power consumption in tracking mode under open sky conditions. Always Locate is an intelligent control of periodic mode. Depending on the environment and motion conditions, GNS902 can adjust the on/off time to achieve balance of positioning accuracy and power consumption. The best power saving will be made under good reception in stationary mode. Critical reception conditions and dynamic movements will need full activity of the GNSS engine which causes nominal power requirements (28mA typ in tracking mode). (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 6 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 3.5 Logger function GNS902 provides an autonomous logger function that automatically stores position information in an internal 128kB flash memory. A complete tracking unit can be realized without any external CPU or memory. The parameters for logging are programmable via the NMEA command interface. The following parameter can be set to optimize logging time: - logger rate The commands for logger include: - start logging - stop logging - erase memory - readout memory please refer to the NMEA_Interface_manual_MTK_Vx for details. Min 1/15 Logger data rate Logger data memory Logger trigger Internal Logger Function Typ max unit 1 1/s 128 kBytes programm able Flash memory Logger can be triggered on various events Logger firmware options (on request) The logger is configured to record the "Basic" content. Other content setting can be ordered as firmware options. The following options can be statically defined by firmware build. Please note that firmware options are bound to MOQ. Name Basic Racing Search Saving All Record size 16 20 19 13 23 Content UTC O O O O O fixtype O O O O Lat O O O O O Lon O O O O O Alt O O O speed heading O O O O O hdop satNo O O O O Checksum O O O O O 3.6 Active interference cancellation (MTAIC) Because different wireless technologies like Wi-Fi, GSM/GPRS, 3G/4G, Bluetooth are integrated into portable systems, the harmonic of RF signals may influence the GPS reception. The multi-tone active interference canceller can reject external RF interference which come from other active components on the main board, thus improving the performance of GPS reception. (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 7 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification GNS902 can cancel up to 12 independent continuous wave (CW) channels having signal levels of up to -80dBm. The functionality is enabled by default and increases power consumption by about 1mA. 3.7 AGPS with EPO data AGPS (assisted GPS) allows to shorten TTFF (TimeToFirstFix) by injecting ephemeris data from an external source into the module's memory. With the help of these data, the module does not need to acquire satellite positions by receiving the data from the satellites. Depending on time and position information, that is still available in the module memory, the TTFF can be reduced to just a few seconds. The GNS AGPS service is based on a short term predicted data service. The predicted data will be fully processed by the GPS engine. The host must load the data from the web and transfer them over the UART into the module: 1. Check GNS902 module EPO (Extended Prediction Orbit) data for validity by comparing the time. 2. Connect to web server through network connection (GPRS, WLAN, LAN,..). 3. Download file. There are just two files, covering all GPS satellites. The first file (MTK7d.EPO) is for 7 days (53kB), the other is 106Kbytes for 14 days (MTK14d.EPO) 4. "Parse" file, using software example. This is quite easy, there must be added some header bytes and a checksum and a control counter. GNS offers software support on this. 5. Download to GNS902 receiver. Please refer to the NMEA_Interface_manual_MTK_Vx for details. If the host has low memory available, there's no need to save the whole file. The steps 3..5 can be done frame by frame needing less than 2kBytes of buffer memory. Code samples and support for several platforms are available from GNS (in preparation). Thanks to the predicted system, download data stay valid for up to 14 days. Therefore, users can initiate the download everytime and benefit from using (W)LAN instead of using expensive GSM. File size will be ~50kBytes for a one week prediction data set. AGPS characteristics System File size for data download Maximum prediction time TTFF TTFF 7 53 14 1 15 kB days sec sec 6hrs predicted data 1 week prediction data Time and last position available Last position available 3.8 EASYTM self generated prediction data feature GNS902 includes an internal prediction system, that allows to sample satellite orbit data during operation and use that data to speed up TTFF on later starts.The prediction time frame is up to three days forward. Although this prediction feature does not provide the very short TTFF that is achieved using AGPS, it can help to find a fix solution faster and in weak signal condition scenario. Prediction data will be kept in memory as long as VBACKUP is present. This option is activated by default. (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 8 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification Note: The EASY functionality is only supported, if "VBACKUP" pin is conntected and the NMEA update rate is 1Hz. 3.9 Pulse Per Second (PPS) GNS902 provides a Pulse Per Second (PPS) hardware output pin for timing purposes. After calculation of a 3D position fix (default setting), the PPS signal is accurately aligned to the GPS second boundaries. The pulse generated is approximately 100 milliseconds in duration and the repetition rate is 1 second. On request PPS output can activated on a 2D- fix or after power-up of the module, providing a time accuracy decreased PPS signal. T2 T1 T1 = 100ms T2 = 1sec GNS902 module provides an exceptionally low RMS jitter of typical 10 nanoseconds. 1PPS pulse duration 1PPS time jitter - PPS characteristics based upon a 3D-fix 100 msec 10 nsec RMS Pulse rising edge deviation from expected pulse time, measured with full 3D fix (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 9 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 1PPS rise and fall time 5 nsec 10%..90%, load is 10k||5pF 3.10 SBAS (Satellite Based Augmentation) support GNS902 supports Satellite Based Augmentation for improvement of the navigation precision. Correction data is sent from geostationary satellites to the GPS/GLONASS receiver. GNS902 supports European, US, and Asian augmentation systems (EGNOS, WAAS, GAGAN, MSAS, QZSS) to enable precision improvements in nearly every region of the world. SBAS is active by default and will automatically track the available SBAS satellites. It can be disabled by NMEA command. See document NMEA_Interface_manual_MTK_Vx for details 3.11 binary output GNS902 allows to reduce data transfer to host to a minimum. Reduced data transfer can save host processor activity times and thus reduce system power consumption. 3.12 GPS/GLONASS almanac and ephemeris data For quick re-acquisition of the GPS/GLONASS receiver after off-times, the GPS/GLONASS engine should have access to almanac and ephemeris data. This data is permanently stored inside GNS902 module, even if all power supplies have been removed. When the receiver is powered-up again, the data will be used to allow a quick re-acquisition, as soon as a coarse time information is available. Time will be available immediately, when RTC is kept running. 3.13 Real time clock (RTC) GNS902 has a real time clock with 32,768Hz crystal on board. As long as VBACKUP is connected to a power source, the real time clock and the module memory can be kept alive at very low power consumption of just 15uA. The RTC will track the current time and enable the module to start from sleep states with very fast time to first Fix (TTFF). 3.14 UART interface GNS902 core and I/O sections work at 3.3V nominal. Absolute Maximum Ratings should not be exceeded. Should the GNS902 be interfaced to a host with I/O at higher/lower levels, level shifters should be used. UART baud rate is 9600baud by default. The baud rate can be modified to higher rates by a NMEA software command. See document NMEA_Interface_manual_MTK_Vx for details. UART Default Settings Parameter Value Baud rate Data length Stop bit Parity 9600 8 bits 1 None (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 10 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 3.15 Module default settings The GNS902 receiver comes with default settings, which are persistently programmed. Whenever power is removed from the module (both VCC and VBACKUP), the settings will be reset to the values shown in the following table. Default settings Setting Default value UART setting Fix frequency (update rate) NMEA sentences NMEA rate DGPS option Datum MTAIC Logging parameters 9600,8,N,1 1/sec Refer to chapter "NMEA output sentences" Once a second: RMC,GSA,VTG,GGA every 5 sec :GSV sentences SBAS enabled WGS 84 enabled cyclic / Content Basic / Interval 15 sec On request, other options can be selected as preprogrammed (persistent default) options. Please contact the GNS support for your project requirements. Note : Customized options are solely available for fixed order lots. (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 11 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 4 TYPICAL APPLICATION BLOCK DIAGRAM 4.1 Typical System Overview Mobile device Power Management VCC V Backup 3.3V GNS902 UART RX UART TX Host Processor MMI (keys, display) (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 12 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 5 GPS/GLONASS characteristics 5.1 GPS/GLONASS characteristics Parameter Min Typ Max Unit Note general Frequency Datum AGPS Output data frequency Navigation&tracking sensitivity1 Acquisition sensitivity1 Reacquisition sensitivity1 TTFF hotstart1 TTFF autonomous warm start1 TTFF autonomous cold start1 Reacquisition time1 Number of channels tracking Number of acquisition channels Dimension Weight 1575.42 1598.0625~ 1609.3125 7 1/10 GPS ACTIVE (acquisition) GPS ACTIVE (tracking) Backup current @ 3V 14 10 1 -165 -148 -163 1 33 35 <1 33 99 15.7x10x2 0.48 Power consumption MHz GPS L1 MHz GLONASS L1 days 1/sec dBm dBm dBm sec sec sec sec mm g 28 mA 23 mA 15 uA WGS84 Configurable autonomous Cold start Hot start All SVs @-130dBm All SVs @-130dBm All SVs @-130dBm All SVs @-130dBm Tolerance is +/-0.2 mm TBD NMEA frequency = 1/sec,SBAS enabled, MTAIC enabled TBD NMEA frequency = 1/sec, SBAS enabled, MTAIC enabled Accuracy Position Position Velocity Velocity error (50%CEP) error (50%CEP) error error Operation altitude Operation velocity Operation acceleration 1 - 3 2.5 0.1 0.05 - - - ITAR limits 18,000 515 4 m m m/s m/s Without aid 2D-RMS Using (SBAS) 2D-RMS Without aid Using (SBAS) m m/s G Note: based on chip specifications (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 13 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 6 ELECTRICAL SPECIFICATION 6.1 Absolute Maximum Ratings Parameter Supply voltage range: Vcc Backup voltage: VBACKUP Value Unit 3.0 to 4.3 2 to 4.3 V V 6.2 Recommended Operating Conditions Parameter Min Typ Max Unit Vcc Vcc ripple voltage 3.0 3.3 4.3 V 50 VBACKUP 2.0 3.0 4.3 V RX0 TTL H Level RX0 TTL L Level TX0 TTL H Level TX0 TTL L Level 2.0 0 2.4 0 Vcc 0.8 2.8 0.4 V V V V Storage temperature -50 +90 C Operating temperature -40 +85 C Note supply voltage mVpp Backup voltage for RTC and memory retention, must be available during normal operation Condition: VCC=3.0V~4.3V Condition: VCC=3.0V~4.3V Condition: VCC=3.0V~4.3V Condition: VCC=3.0V~4.3V (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 14 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 7 PIN CONFIGURATION Top View (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 15 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification Pin 1 2 3 4 Name GND WAKEUP NC 3D_FIX I/O I Description & Note Ground Wakeup input (TBD) leave open O Not conected 3D-Fix Indicator The 3D_FIX is assigned as a fix flag output. If not used, keep floating. Before 2D Fix The pin will continuously toggle with 1 Hz. output 100ms high-level and 0.9s low-level signal After 2D or 3D Fix The pin will continuously output low-level signal This pin may not connected to high-level at power-on sequence. 5 6 7 GND GND RXA I Ground Ground Serial Data Input A for NMEA commands (TTL) 8 TXA O Serial Data Output A for NMEA output (TTL) 9 RXB I Serial Data Input B 10 11 NC 1PPS O Not connected 1PPS Time Mark Output 2.8V CMOS Level 12 13 NC VBACKUP P Not conected Backup power input for RTC & navigation data keep 14 VCC P Main DC power input 15 16 17 18 19 GND GND NC NC RESET I Ground Ground Not conected Not conected System reset pin 20 GND This is the UART-A receiver of the module. It is used to receive commands from system This is the UART-A transmitter of the module. It outputs GPS information for application. This is the UART-B receiver of the module. It is used to receive RTCM data from system This pin provides one pulse-per-second output from the module and synchronizes to GPS time. Keep floating if not used. This connects to the backup power of the GPS module. Power source (such as battery) connected to this pin will help the GPS chipset in keeping its internal RTC running when the main power source is turned off. The voltage should be kept between 2.8V~4.3V, Typical 3.3V. If VBACKUP power was not reserved, the GPS receiver will perform a lengthy cold start every time it is poweredon because previous satellite information is not retained and needs to be re-transmitted. This pin must be connected for normal operation. The main DC power supply for the module. The voltage should be kept between from 2.8V to 4.3V. The ripple must be limited under 50mVpp (Typical: 3.3V). An external reset applied to this pin overrides all other internal controls. RESET# is an active low signal. Pulling this pin low for at least 20 s causes a system reset. Ground (1) I = INPUT; O = OUTPUT; I/O = BIDIRECTIONAL; P = POWER PIN; ANA = ANALOG PIN. (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 16 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 8 PHYSICAL DIMENSIONS TOP VIEW all units in mm, tolerance is 0.2mm 2.0 0.90 0.55 (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 17 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 9 RECOMMENDED PAD LAYOUT all units in mm Footprint Top View (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 18 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 10 DESIGN GUIDELINES Although GNS902 GPS/GLONASS receiver provides best performance at low power consumption, special care should be taken to provide clean signal and clean power supplies. Power lines should be blocked near to the receiver with low ESR capacitors. Radiated noise from neighbour components may also reduce the performance of the receiver. Please refer to "GNS902 Starter Kit User Manual" for more informations, downloadable at the GNS forum: www.forum.gns-gmbh.com . 10.1 PCB LAYOUT GUIDELINES GNS902 uses a high performance chip antenna design. For optimum performance, a ground plane area is needed on the main board. This area should be at least 20 x 30mm, a larger ground like 30 x 60mm is recommended. The groundplane can be part of the main ground layer of the mainboard, some (small) components in the neighbourhood of the antenna are acceptable. Do not place any bulky or metallic components near to the antenna (in a distance below 30mm) to avoid unwanted electromagnetic shielding effects. It's recommended to place GNS 902 at the rim of the main PCB, so that the antenna has a wide unobstructed working angle. (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 19 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification Groundplane on top & bottom. Be sure to solder these pads reliably ! Clearence area. Keep clear on all layers ! Position of chip antenna on 902 module The marked clearance area below the antenna must be kept clear in any case ! Do not design any copper tracks or planes in the clearance area ! The two ground solder pads near the chip antenna must be reliably soldered to mainboard groundplanes to make the antenna work at high performance. Please do not place any shielding or lids in the area 5mm below your PCB under the Clearance area. Plastic enclosures can also have impact on the antenna. Avoid that the antenna is in touch with any enclosure parts. Product testing should be performed with the PCB already mounted in the final enclosure. Generally the rules for good and low noise design should be followed: Use a solid ground plane, best on layer 2 of the mainboard Keep noisy components (C, switch mode supplies) as far as possible away from sensitive antenna inputs Place decoupling capacitors near to the source of noise and provide a short and low induction connection to ground (use multi-vias if needed) EMC filters or noise filtering coils or beads can help to reduce the noise level further. Select system clocks in a way, that no harmonics will match the GPS/Glonass frequency 0f 1575.42 to 1610 MHz (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 20 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 11 NMEA DATA interface GNS902 provides NMEA (National Marine Electronics Association) 0183 compatible data. A set of proprietary NMEA commands is available to send control messages to the receiver. These commands are described in a separate document: NMEA_Interface_manual_MTK_Vx. For standard operation, no commands are needed; the module will start outputting NMEA sentences after power supply has been attached. GNS902 will always start communication output with 9600 bit per second. If non standard options are needed (f.e. other baud rate , other NMEA sequence) they can be programmed from host controller during runtime. Important note : Options set by using NMEA command interface are not persistent! They will be lost when power is removed. A backup supply at VBACKUP will be sufficient to keep them. 11.1 NMEA output sentences NMEA output sentences Type content RMC GGA GLL GSA VTG GSV Recommended Minimum Navigation Information Fix Data, Time, Position and fix related data Geographic Position - Latitude/Longitude DOP and active satellites Course and Speed Information relative to the Ground Satellites in view NMEA output sentences indentifier, related to its GNSS system: NMEA output identifier System GPS GPS+GLONASS GGA GPGGA GPGGA GSA GPGSA GNGSA GSV RMC GPGSV GPRMC GPGSV GPRMC1 or GLGSV GNRMC Note1: Before 3D fix RMC output is GPRMC, after 3D fix it changes to GNRMC. VTG GPVTG GPVTG Refer to NMEA_protocol document available at GNS forum www.forum.gns-gmbh.com for more information. (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 21 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 11.2 NMEA command interface GNS902 NMEA command interface allows to control settings and the extended functions. The command interface specification is available in an extra document: NMEA_Interface_manual_MTK_Vx. Two groups of commands are available: Setting commands do modify the behavior of the module. Note : Modified settings will be valid as long as the module is powered through VCC or VBACKUP. (f.e. : setting of a new baud rate). After removing VCC and VBACKUP, all settings are reset to their default values. Action commands will perform the specified action one time after the command has been received. (f.e. : request for cold start) Commands are always started with $PTMK, directly followed by the command number 000..999. Each command must be terminated by *<chksum>and a <CR><LF>. The checksum calculation is simple, just XOR all the bytes between the $ and the * (not including the delimiters themselves). Then use the hexadecimal ASCII format. (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 22 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 12 MATERIAL INFORMATION Complies to ROHS standard ROHS documentations are available on request Contact surface: gold over nickel 13 RECOMMENDED SOLDERING REFLOW PROFILE T[C] 300 250C max 250C for 10 sec max 230C for 40 sec max 200 160C 190C 120 sec reflow solder 100 100 200 t[sec] Notes: 1. GNS902 should be soldered in upright soldering position. In case of head-over soldering, please prevent shielding / GNS902 receiver from falling down. 2. Do never exceed maximum peak temperature 3. Reflow cycles allowed : 1 time 4. Do not solder with Pb-Sn or other solder containing lead (Pb) 5. This device is not applicable for flow solder processing 6. This device is not applicable for solder iron process (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 23 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 14 PACKAGE INFORMATION 14.1 TAPE (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 24 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 14.2 REEL : Number of devices: 1500 pcs/reel 15 ORDERING INFORMATION Ordering information Type GNS902 Part# 4037735105171 label marking GNS902 FWV YYWW SN Description GNS902receiver FWV => Firmware version YYWW => date code SN => serial number (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 25 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 16 ENVIRONMENTAL INFORMATION This product is free of environmental hazardous substances and complies with 2002/95/EC. (RoHS directive). 17 MOISTURE SENSITIVITY This device must be prebaked before being put to reflow solder process. Disregarding may cause destructive effects like chip cracking, which leaves the device defective ! Shelf life 6 months , sealed Possible prebake recommendations 12 hrs @ 60C Floor life (time from prebake to solder process) <72 hrs (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 26 GPS/GLONASS receiver GNS902 Datasheet V1.3 preliminary specification 18 DOCUMENT REVISION HISTORY V1.0 V1.1 V1.3 April 8 2014 July 8 2014 Oct 6 2014 M.Reiff P.Skaliks P.Skaliks initial document First preliminary release Added logger information 19 RELATED DOCUMENTS Title Description / file Available from NMEA_Interface_manual_MTK_Vx Detailed description of NMEA commands www.forum.gns-gmbh.com www.gns-gmbh.com GNS202/902 StarterKit user manual User manual for the GNS902 receiver based evaluation kit www.forum.gns-gmbh.com www.gns-gmbh.com GNS GMBH 2014 THE INFORMATION IN THIS DOCUMENTATION DOES NOT FORM ANY QUOTATION OR CONTRACT. TECHNICAL DATA ARE DUE TO BE CHANGED WITHOUT NOTICE. NO LIABILITY WILL BE ACCEPTED BY THE PUBLISHER FOR ANY CONSEQUENCE OF THIS DOCUMENT'S USE. REPRODUCTION IN WHOLE OR IN PART IS PROHIBITED WITHOUT THE PRIOR WRITTEN CONSENT OF THE COPYRIGHT OWNER (c) GNS-GmbH 2014 V 1.3, oct 6th 2014 27