GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
1
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
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
2
using MTAICTM ( 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
• 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
1 Note: Measured navigation sensitivity at RF input of chipset
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
3
2 INDEX
1 INTRODUCTION ----------------------------------------------------------------------------------------- 1
2 INDEX --------------------------------------------------------------------------------------------------- 3
3 FUNCTIONAL DESCRIPTION ---------------------------------------------------------------------------- 4
3.1 System description --------------------------------------------------------------------------------------------------------- 4
3.2 Block diagram -------------------------------------------------------------------------------------------------------------- 4
3.3 GPS and GLONASS simultaneous operation ------------------------------------------------------------------------------ 5
3.4 Power Management Features ---------------------------------------------------------------------------------------------- 5
3.5 Logger function ------------------------------------------------------------------------------------------------------------- 7
3.6 Active interference cancellation (MTAIC) --------------------------------------------------------------------------------- 7
3.7 AGPS with EPO data -------------------------------------------------------------------------------------------------------- 8
3.8 EASYTM self generated prediction data feature ---------------------------------------------------------------------------- 8
3.9 Pulse Per Second (PPS) ---------------------------------------------------------------------------------------------------- 9
3.10 SBAS (Satellite Based Augmentation) support ------------------------------------------------------------------------- 10
3.11 binary output ------------------------------------------------------------------------------------------------------------- 10
3.12 GPS/GLONASS almanac and ephemeris data --------------------------------------------------------------------------- 10
3.13 Real time clock (RTC) ---------------------------------------------------------------------------------------------------- 10
3.14 UART interface ------------------------------------------------------------------------------------------------------------ 10
3.15 Module default settings -------------------------------------------------------------------------------------------------- 11
4 TYPICAL APPLICATION BLOCK DIAGRAM ------------------------------------------------------------ 12
4.1 Typical System Overview ------------------------------------------------------------------------------------------------ 12
5 GPS/GLONASS characteristics ------------------------------------------------------------------------ 13
5.1 GPS/GLONASS characteristics ------------------------------------------------------------------------------------------- 13
6 ELECTRICAL SPECIFICATION ------------------------------------------------------------------------- 14
6.1 Absolute Maximum Ratings ---------------------------------------------------------------------------------------------- 14
6.2 Recommended Operating Conditions ----------------------------------------------------------------------------------- 14
7 PIN CONFIGURATION --------------------------------------------------------------------------------- 15
8 PHYSICAL DIMENSIONS ------------------------------------------------------------------------------ 17
9 RECOMMENDED PAD LAYOUT ------------------------------------------------------------------------ 18
10 DESIGN GUIDELINES -------------------------------------------------------------------------------- 19
10.1 PCB LAYOUT GUIDELINES ----------------------------------------------------------------------------------------------- 19
11 NMEA DATA interface -------------------------------------------------------------------------------- 21
11.1 NMEA output sentences -------------------------------------------------------------------------------------------------- 21
11.2 NMEA command interface------------------------------------------------------------------------------------------------ 22
12 MATERIAL INFORMATION --------------------------------------------------------------------------- 23
13 RECOMMENDED SOLDERING REFLOW PROFILE --------------------------------------------------- 23
14 PACKAGE INFORMATION ---------------------------------------------------------------------------- 24
14.1 TAPE ----------------------------------------------------------------------------------------------------------------------- 24
14.2 REEL ----------------------------------------------------------------------------------------------------------------------- 25
15 ORDERING INFORMATION -------------------------------------------------------------------------- 25
16 ENVIRONMENTAL INFORMATION ------------------------------------------------------------------- 26
17 MOISTURE SENSITIVITY ---------------------------------------------------------------------------- 26
18 DOCUMENT REVISION HISTORY -------------------------------------------------------------------- 27
19 RELATED DOCUMENTS ------------------------------------------------------------------------------ 27
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
4
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
32.768kHz
crystal
26MHz
TCXO
SAW filter
+Low Noise
Amplifier
GND
1,5,6,15,16,20
13
14
VCC
VBACKUP
4
3D-Fix
11
1PPS
TXA
8
7
RXA
RXB
9
2
WAKEUP
19
RESET
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
5
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.
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
6
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).
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
7
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.
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
Record
size
Content
UTC
fixtype
Lat
Lon
Alt
speed
heading
hdop
satNo
Checksum
Basic
16
O
O
O
O
O
O
Racing
20
O
O
O
O
O
O
O
O
Search
19
O
O
O
O
O
O
O
O
Saving
13
O
O
O
O
All
23
O
O
O
O
O
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.
Internal Logger Function
Min
Typ
max
unit
Logger data rate
1/15
1
1/s
Logger data memory
128
kBytes
Flash memory
Logger trigger
programm
able
Logger can be triggered on
various events
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
8
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.
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.
AGPS characteristics
System
6hrs predicted data
File size for data download
53
kB
1 week prediction data
Maximum prediction time
7
14
days
TTFF
1
sec
Time and last position available
TTFF
15
sec
Last position available
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
9
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.
GNS902 module provides an exceptionally low RMS jitter of typical 10 nanoseconds.
PPS characteristics based upon a 3D-fix
1PPS pulse duration
-
100
-
msec
1PPS time jitter
-
10
nsec
RMS
Pulse rising edge deviation from
expected pulse time, measured
with full 3D fix
T1
T2
T1 = 100ms
T2 = 1sec
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
10
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
9600
Data length
8 bits
Stop bit
1
Parity
None
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
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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
9600,8,N,1
Fix frequency (update rate)
1/sec
NMEA sentences
Refer to chapter “NMEA output sentences”
NMEA rate
Once a second: RMC,GSA,VTG,GGA every 5 sec :GSV sentences
DGPS option
SBAS enabled
Datum
WGS 84
MTAIC
enabled
Logging parameters
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.
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
12
4 TYPICAL APPLICATION BLOCK DIAGRAM
4.1 Typical System Overview
Mobile device
Host Processor
MMI
(keys, display)
Power
Management
3.3V
GNS902
UART RX
UART TX
VCC
V Backup
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
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5 GPS/GLONASS characteristics
5.1 GPS/GLONASS characteristics
Parameter
Min
Typ
Max
Unit
Note
general
Frequency
1575.42
MHz
GPS L1
1598.0625~
1609.3125
MHz
GLONASS L1
Datum
WGS84
AGPS
7
14
days
Configurable
Output data frequency
1/10
1
10
1/sec
Navigation&tracking sensitivity1
-165
dBm
autonomous
Acquisition sensitivity1
-148
dBm
Cold start
Reacquisition sensitivity1
-163
dBm
Hot start
TTFF hotstart1
1
sec
All SVs @-130dBm
TTFF autonomous warm start1
33
sec
All SVs @-130dBm
TTFF autonomous cold start1
35
sec
All SVs @-130dBm
Reacquisition time1
<1
sec
All SVs @-130dBm
Number of channels tracking
33
Number of acquisition channels
99
Dimension
15.7x10x2
mm
Tolerance is +/-0.2 mm
Weight
0.48
g
Power consumption
35*
mA
NMEA frequency = 1/sec*
GPS ACTIVE (acquisition)
28
mA
TBD NMEA frequency = 1/sec,SBAS
enabled, MTAIC enabled
GPS ACTIVE (tracking)
23
mA
TBD NMEA frequency = 1/sec, SBAS
enabled, MTAIC enabled
Backup current @ 3V
15
uA
Accuracy
Position error (50%CEP)
-
3
-
m
Without aid 2D-RMS
Position error (50%CEP)
-
2.5
-
m
Using (SBAS) 2D-RMS
Velocity error
-
0.1
-
m/s
Without aid
Velocity error
-
0.05
-
m/s
Using (SBAS)
ITAR limits
Operation altitude
-
18,000
m
Operation velocity
-
-
515
m/s
Operation acceleration
-
-
4
G
1 Note: based on chip specifications
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
14
6 ELECTRICAL SPECIFICATION
6.1 Absolute Maximum Ratings
Parameter
Value
Unit
Supply voltage range: Vcc
3.0 to 4.3
V
Backup voltage: VBACKUP
2 to 4.3
V
6.2 Recommended Operating Conditions
Parameter
Min
Typ
Max
Unit
Note
Vcc
3.0
3.3
4.3
V
supply voltage
Vcc ripple voltage
50
mVpp
VBACKUP
2.0
3.0
4.3
V
Backup voltage for RTC and
memory retention, must be
available during normal
operation
RX0 TTL H Level
2.0
Vcc
V
Condition: VCC=3.0V~4.3V
RX0 TTL L Level
0
0.8
V
Condition: VCC=3.0V~4.3V
TX0 TTL H Level
2.4
2.8
V
Condition: VCC=3.0V~4.3V
TX0 TTL L Level
0
0.4
V
Condition: VCC=3.0V~4.3V
Storage temperature
-50
+90
°C
Operating temperature
-40
+85
°C
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
15
7 PIN CONFIGURATION
Top View
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
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16
Pin
Name
I/O
Description & Note
1
GND
Ground
2
WAKEUP
I
Wakeup input (TBD) leave open
3
NC
Not conected
4
3D_FIX
O
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
GND
Ground
6
GND
Ground
7
RXA
I
Serial Data Input A for NMEA commands (TTL)
This is the UART-A receiver of the module. It is used to receive commands from system
8
TXA
O
Serial Data Output A for NMEA output (TTL)
This is the UART-A transmitter of the module. It outputs GPS information for application.
9
RXB
I
Serial Data Input B
This is the UART-B receiver of the module. It is used to receive RTCM data from system
10
NC
Not connected
11
1PPS
O
1PPS Time Mark Output 2.8V CMOS Level
This pin provides one pulse-per-second output from the module and synchronizes to GPS time. Keep floating if
not used.
12
NC
Not conected
13
VBACKUP
P
Backup power input for RTC & navigation data keep
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 powered-
on because previous satellite information is not retained and needs to be re-transmitted.
This pin must be connected for normal operation.
14
VCC
P
Main DC power input
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).
15
GND
Ground
16
GND
Ground
17
NC
Not conected
18
NC
Not conected
19
RESET
I
System reset pin
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 μs causes a system reset.
20
GND
Ground
(1) I = INPUT; O = OUTPUT; I/O = BIDIRECTIONAL; P = POWER PIN; ANA = ANALOG PIN.
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
17
8 PHYSICAL DIMENSIONS
TOP VIEW
all units in mm, tolerance is ±0.2mm
0.90
0.55
2.0
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
18
9 RECOMMENDED PAD LAYOUT
all units in mm
Footprint Top View
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
19
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.
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
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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 (µC, 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
Position of chip
antenna on
902 module
Groundplane on
top & bottom.
Clearence area.
Keep clear on all
layers !
Be sure to solder
these pads
reliably !
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
21
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
Recommended Minimum Navigation Information
GGA
Fix Data, Time, Position and fix related data
GLL
Geographic Position - Latitude/Longitude
GSA
DOP and active satellites
VTG
Course and Speed Information relative to the Ground
GSV
Satellites in view
NMEA output sentences indentifier, related to its GNSS system:
NMEA output identifier
System
GGA
GSA
GSV
RMC
VTG
GPS
GPGGA
GPGSA
GPGSV
GPRMC
GPVTG
GPS+GLONASS
GPGGA
GNGSA
GPGSV
GLGSV
GPRMC1 or
GNRMC
GPVTG
Note1: Before 3D fix RMC output is GPRMC, after 3D fix it changes to GNRMC.
Refer to NMEA_protocol document available at GNS forum www.forum.gns-gmbh.com for more
information.
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
22
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.
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
23
12 MATERIAL INFORMATION
Complies to ROHS standard
ROHS documentations are available on request
Contact surface: gold over nickel
13 RECOMMENDED SOLDERING REFLOW PROFILE
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
100
200
300
t[sec]
100
200
T[°C]
250°C max
250°C for 10 sec max
230°C for 40 sec max
160°C 190°C 120 sec
reflow solder
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
24
14 PACKAGE INFORMATION
14.1 TAPE
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
25
14.2 REEL
:
Number of devices: 1500 pcs/reel
15 ORDERING INFORMATION
Ordering information
Type
Part#
label marking
Description
GNS902
4037735105171
GNS902
FWV
YYWW
SN
GNS902receiver
FWV => Firmware version
YYWW => date code
SN => serial number
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
26
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 @ 60°C
Floor life (time from prebake to solder process)
<72 hrs
GPS/GLONASS receiver
GNS902
Datasheet V1.3
preliminary specification
© GNS-GmbH 2014
V 1.3, oct 6th 2014
27
18 DOCUMENT REVISION HISTORY
V1.0
April 8 2014
M.Reiff
initial document
V1.1
July 8 2014
P.Skaliks
First preliminary release
V1.3
Oct 6 2014
P.Skaliks
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