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Combination GPS/GLONASS Receivers:
GPS and GLONASS Combination Antennas:
NDV4554
High-Performance 88 Channel GLONASS/GPS Receiver
The NDV4554 offers GPS+GLONASS positioning to provide increased satellite availability for positioning in challenging environments at a very cost-effective price. It offers 24 tracking channels of L1 GPS and GLONASS code and carrier phase tracking for increased positioning accuracy and availability.

The NDV4554 features 88 channel GPS receiver with fast time to first fix and improved -145dBm cold start sensitivity. The superior cold start sensitivity allows it to acquire, track, and get position fix autonomously in difficult weak signal environment. The receiver’s -159dBm navigation sensitivity allows continuous position coverage in nearly all application environments. The high performance search engine is capable of testing 10,000,000 time-frequency hypotheses per second, offering industry-leading signal acquisition and TTFF speed.

The receiver is suitable for in vehicle car navigation system that requires high performance continuous navigation and low cost.

ndv4554
Features
88 Channel GLONASS+GPS L1 C/A Code
Perform 10 million time-frequency hypothesis testing per second
Open sky hot start 1 sec
Open sky cold start 29 sec
Cold start sensitivity -145dBm
Navigation sensitivity -159dBm
Accuracy 2.5m CEP
400mW acquisition
250mW tracking
Operating temperature -40 ~ +85ºC
RoHS compliant
Applications
Automotive Navigation
Vehicle Tracking
Marine Navigation
Timing reference
TECHNICAL SPECIFICATIONS
Receiver Type
L1 C/A code, 88-channel
Modes
GLONASS, GPS, GLONASS + GPS
Accuracy
Position:   2.5m CEP
Velocity:    0.1m/sec
Time:        60ns
Startup Time
1 second hot start under open sky
< 29 second warm start under open sky (average)
29 second cold start under open sky
Reacquisition
1s
Sensitivity
-145dBm cold start
-159dBm tracking
Update Rate
1Hz
Operational Limits
Altitude <18,000m or velocity < 515m/s
Serial Interface
3.3V LVTTL level
Protocol
NMEA-0183 V3.01
GPGGA, GNGLL,
GNGNS, GPGSA, GLGSA, GNGSA
GPGSV, GLGSV, GNVTG, GNRMC
9600 baud, 8, N, 1
Datum
Default WGS-84
User definable
Input Voltage
3.3V DC +/-5%
Power Consumption
400mW acquisition 250mW tracking
Dimension
54mm L x 45mm W
Weight:
12g
Interface Connector
20 pin male header, 2.0mm pitch
Operating Temperature
-40oC ~ +85oC
Storage Temperature
-55 ~ +100oC
Humidity
5% ~ 95%
BLOCK DIAGRAM
Block digram
Interface
Interface
PINOUT DESCRIPTION
Pin No.
Name
Description
1
VIN33
+3.3V +/- 5% DC power input
2
GND
System ground
3
NC
No connection
4
NC
No connection
5
NC
No connection
6
NC
No connection
7
ENA
Enable control. 1:ON, 0:OFF
8
NC
No connection
9
NC
No connection
10
NC
No connection, empty pin
11
RESETN
External active-low reset input. VIH > 2.3V, VIL<0.8V Can be left NC if not used.
12
NC
No connection
13
FTXD0
UART serial data output, 3V LVTTL.
One full-duplex asynchronous serial UART port is implemented. This UART output is normally used for sending position, time and velocity information from the receiver in NMEA-0183 format. When idle, this pin output HIGH. 2.8V < VOH < 3.3V, 0V < VOL< 0.5V
14
FRXD0
UART serial data input, 3V LVTTL.
One full-duplex asynchronous serial UART port is implemented. This UART input is normally for sending commands or information to the receiver in GlonassCentral binary protocol. In the idle condition, this pin should be driven HIGH. If the driving circuitry is powered independently of NDV4554, ensure that this pin is not driven to HIGH when primary power to NDV4554is removed, or a 10K-ohm series resistor can be added to minimize leakage current from application to the powered off module. VIH > 2.3V, VIL<0.8V
15
P1PPS
One-pulse-per-second (1PPS) time mark output, 3V LVTTL. The rising edge synchronized to UTC second when getting 3D position fix. The pulse duration is about 4msec at rate of 1 Hz. 2.8V < VOH < 3.3V, 0V < VOL< 0.5VOne-pulse-per-second (1PPS) time mark output, 3V LVTTL. The rising edge synchronized to UTC second when getting 3D position fix. The pulse duration is about 4msec at rate of 1 Hz. 2.8V < VOH < 3.3V, 0V < VOL< 0.5V
16
VBAT
Backup supply voltage for internal RTC and backup SRAM, 1.5V ~ 6V. VBAT must be applied whenever VIN33 is applied. This pin should be powered continuously to minimize the startup time. If VIN33 and VBAT are both removed, the receiver will be in factory default mode upon power up, all user configuration set is lost. For applications the does not care cold starting every time, this pin can be connect to VIN33.
17
FTXD1
UART serial data output, 3V LVTTL.
One full-duplex asynchronous serial UART port is implemented. When idle, this pin output HIGH. 2.8V < VOH < 3.3V, 0V < VOL< 0.5V
18
FRXD1
UART serial data input, 3V LVTTL.
One full-duplex asynchronous serial UART port is implemented. In the idle condition, this pin should be driven HIGH. If the driving circuitry is powered independently of NDV4554, ensure that this pin is not driven to HIGH when primary power to NDV4554is removed, or a 10K-ohm series resistor can be added to minimize leakage current from application to the powered off module.VIH > 2.3V, VIL<0.8V
19
VIN33
+3.3V +/- 5% DC power input
20
GND
System ground
MECHANICAL DIMENSION
MECHANICAL DIMENSION
ELECTRICAL SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Parameter Minimum Maximum Condition
Supply Voltage (VIN33)) -0.5 3.6 Volt
Backup Battery Voltage (VBAT) -0.5 6 Volt
Input Pin Voltage -0.5 VIN33+0.5 Volt
Input Power at RFIN   +5 dBm
Storage Temperature -55 +100 degC
OPERATING CONDITIONS
Parameter Min Typ Max Unit
Supply Voltage (VIN33) 3 3.3 3.6 Volt
Acquisition Current (exclude active antenna current)   120   mA
Tracking Current (exclude active antenna current)   76   mA
Backup Voltage (VBAT) 1.5   6 Volt
Backup Current (VIN voltage applied)     1.5 mA
Backup Current (VIN voltage off)     10 uA
Output Low Voltage     0.4 Volt
Output HIGH Voltage 2.4     Volt
Input LOW Voltage     0.8 Volt
Input HIGH Voltage 2     Volt
Input LOW Current -10   10 uA
Input HIGH Current -10   10 uA
RF Input Impedance (RFIN)   50   Ohm
POWER SUPPLY REQUIREMENT
NDV4554requires a stable power supply, avoid ripple on VIN33 pin (<50mVpp). Power supply noise can affect the receiver’s sensitivity. Bypass capacitors should be placed close to the module VIN33 pin, with values adjusted depending on the amount and type of noise present on the supply line.
BACKUP SUPPLY
The purpose of backup supply voltage pin (VBAT) is to keep the SRAM memory and the RTC powered when the module is powered down. This enables the module to have a faster time-to-first-fix when the module is powered on again. The backup current drain is less than 10ìA. In normal powered on state, the internal processor access the SRAM and current drain is higher in active mode
ANTENNA CONSIDERATION
3.3V DC bias voltage is provided on the SMA RF input connector; short circuit current limit is 70mA. Active antenna with gain up to 30dB and noise figure less than 2dB can be used.
NMEA Output Description
The NMEA message output by the GlonassCentral GPS/GLONASS receiver has the following sentence structure:
Structure:
$aaccc,c--c*hh<CR><LF>

The detail of the sentence structure is explained in Table 1.
Table 1: The NMEA sentence structure
character HEX Description
“$” 24 start of the sentence/message
aaccc   address field. The first 2 characters “aa” identify the talker/transmitting terminal (talker identifier). The last 3 characters “ccc” identify the NMEA message type.
“,” 2C the field delimiter
c--c   the data sentence block
“*” 2A the checksum delimiter
hh   checksum field
<CR><LF> 0D0A end of sentence/message (carriage return, line feed)

There are three types of talker identifiers (see section six, NMEA 0183 standard) for the NMEA output from GlonassCentral GPS/GLONASS receiver. The three types of talker identifiers are GP, GL and GN and they stand for the data related to the GPS, GLONASS and the combined system, respectively.

In the default setting, GlonassCentral GPS/GLONASS receiver calculates the PVT solution using the combination of GPS and GLONASS satellites. In some circumstances, however, only the GPS or the GLONASS satellite signals are available for the GPS/GLONASS receiver. The solution may be then performed based on either single or combined satellite systems according to the actual satellite constellation.

Currently, the messages GGA/GNS/GSA/GSV/RMC/VTG are supported in the GPS/GLONASS receiver. The NMEA messages and the corresponding information content are listed in Table 2. The matching talker identifiers for each NMEA message are also listed in Table 2. The combination of talker identifiers and the NMEA messages is used for reporting satellite and navigation information under different satellite constellations. The detail is explained in the following.
Table 2: Supported NMEA Message List
NMEA Message Information Content Possible Talker Identifiers
GGA Time, position, and fix related data for the GlonassCentral receiver. GP
GNS Time, position and fix related data of GPS, GLONASS or combined systems. GN
GSA Receiver operating mode, satellites used in the PVT solution, and DOP values. GP, GL, GN
GSV Number of satellites in view, satellite ID, elevation, azimuth and SNR value. GP, GL
VTG Course and speed relative to the ground. GN
RMC Time, date, position, course and speed data. GN
GGA - Global Positioning System Fix Data
Time, position and fix related data for a GPS receiver.
Format:
$--GGA,hhmmss.ss,llll.lll,a,yyyyy.yyy,a,x,uu,v.v,w.w,M,x.x,M,,zzzz*hh<CR><LF>

Field Name Description
hhmmss.ss UTC Time UTC of position in hhmmss.sss format, (000000.000 ~ 235959.999)
llll.lll Latitude Latitude in ddmm.mmmm format
Leading zeros transmitted
a N/S Indicator Latitude hemisphere indicator, ‘N’ = North, ‘S’ = South
yyyyy.yyy Longitude Longitude in dddmm.mmmm format
Leading zeros transmitted
a E/W Indicator Longitude hemisphere indicator, 'E' = East, 'W' = West
x GPS quality indicator GPS quality indicator
0: position fix unavailable
1: valid position fix, SPS mode
2: valid position fix, differential GPS mode
3: GPS PPS Mode, fix valid
4: Real Time Kinematic. System used in RTK mode with fixed integers
5: Float RTK. Satellite system used in RTK mode. Floating integers 6: Estimated (dead reckoning) Mode
7: Manual Input Mode
8: Simulator Mode
uu Satellites Used Number of satellites in use, (00 ~ 24)
v.v HDOP Horizontal dilution of precision, (00.0 ~ 99.9)
w.w Altitude mean sea level altitude (-9999.9 ~ 17999.9) in meter
x.x Geoidal Separation In meter
zzzz DGPS Station ID Differential reference station ID, 0000 ~ 1023 NULL when DGPS not used
hh Checksum  
When the GGA message is turned on, the talker identifier is always set to GP, regardless of whether the position solution is based on GPS, GLONASS satellites or the combination.
GNS message:
Format::
$--GNS,hhmmss.ss,llll.lll,a,yyyyy.yyy,a,cc,uu,v.v,w.w,x.x,,*hh<CR><LF>

Field Name Description
hhmmss.ss UTC Time UTC of position in hhmmss.sss format, (000000.000 ~ 235959.999)
llll.lll Latitude Latitude in ddmm.mmmm format
Leading zeros transmitted
a N/S Indicator Latitude hemisphere indicator, ‘N’ = North, ‘S’ = South
yyyyy.yyy Longitude Longitude in dddmm.mmmm format
Leading zeros transmitted
a E/W Indicator Longitude hemisphere indicator, 'E' = East, 'W' = West
CC Mode Indicator Two characters with the first indicate the use of GPS satellites, and the second indicate the use of GLONASS satellites.
N: No fix
A: Autonomous, non-differential mode
D: Differential mode
P: Precise, no SA, higher resolution (P-code) used
R: Real Time Kinematic. System used in RTK mode with fixed integers
F: Float RTK. Satellite system used in RTK mode. Floating integers E: Estimated (dead reckoning) Mode
M: Manual Input Mode
S: Simulator Mode
uu Satellites Used Number of satellites in use, (00 ~ 24)
v.v HDOP Horizontal dilution of precision, (00.0 ~ 99.9)
w.w Altitude mean sea level altitude (-9999.9 ~ 17999.9) in meter
x.x Geoidal Separation In meter
hh Checksum  
By default, the receiver uses the GNS message to report the position data. For the GNS message, currently supported talker identifier is GN. The mode indicator is used to denote which GNSS type is used in the navigation solution. There are two characters in the mode indicator. The first character is for GPS system while the second character is for GLONASS system. For example, when only GPS satellites are used for (non-differential) navigation solution, the mode indicator will be “AN”. When only GLONASS satellites are used for (non-differential) navigation solution, the mode indicator will be “NA”. Only when both GPS and GLONASS satellites are used in the (non-differential) navigation solution, the mode indicator will become “AA”.
GSA – GNSS DOP and Active Satellites
GPS receiver operating mode, satellites used in the navigation solution reported by the GGA or GNS sentence and DOP values.
Format::
$--GSA,a,x,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,u.u,v.v,z.z*hh<CR><LF>

Field Name Description
a Mode Mode
‘M’ = Manual, forced to operate in 2D or 3D mode
‘A’ = Automatic, allowed to automatically switch 2D/3D
x Mode Fix type
1 = Fix not available
2 = 2D
3 = 3D
xx Satellite used 1~12 Satellite ID number, 01 to 32, of satellite used in solution, up to 12 transmitted
uu PDOP Position dilution of precision (00.0 to 99.9)
v.v HDOP Horizontal dilution of precision (00.0 to 99.9)
z.z VDOP Vertical dilution of precision (00.0 to 99.9)
hh Checksum  

When only GPS satellites are used in position solution, the talker identifier is GP. When only GLONASS satellites are used in position solution, the talker identifier is GL. When both GPS and GLONASS satellite are used together in the position solution, the talker identifier will be GN. In the third case, the receiver creates two GSA sentences for every epoch. The first GNGSA sentence is used for GPS satellites while the second one is for the GLONASS satellites. In the GSA message, the satellite ID number of the GLONASS satellite is 64+satellite slot number.
GSV – GNSS Satellites in View
Number of satellites (SV) in view, satellite ID numbers, elevation, azimuth, and SNR value. Four satellites maximum per transmission.
Format::
$--GSV,x,u,xx,uu,vv,zzz,ss,uu,vv,zzz,ss,…,uu,vv,zzz,ss*hh<CR><LF>

Field Name Description
x Number of message Total number of GSV messages to be transmitted (1-3)
u Sequence number Sequence number of current GSV message
xx Satellites in view Total number of satellites in view (00 ~ 12)
uu Satellite ID Satellite ID number, GPS: 01 ~ 32, SBAS: 33 ~ 64 (33 = PRN120)
v.v Elevation Satellite elevation in degrees, (00 ~ 90)
zzz Azimuth Satellite azimuth angle in degrees, (000 ~ 359 )
ss SNR C/No in dB (00 ~ 99)
Null when not tracking
hh Checksum  

The GSV sentence has two possible talker identifiers: GP and GL. The GPS/GLONASS receiver outputs separate GSV sentences to report satellite information for GPS and GLONASS systems. The GPGSV is for GPS satellites while GLGSV is for GLONASS satellites. The GN identifier is not supported in GSV message. In the GSV message, the satellite ID number of the GLONASS satellite is 64+satellite slot number.
RMC – Recommended Minimum Specific GNSS Data
Time, date, position, course and speed data provided by a GNSS navigation receiver.
Format::
$--RMC,hhmmss.sss,x,llll.lll,a,yyyyy.yyy,a,x.x,u.u,xxxxxx,,,v*hh<CR><LF>

Field Name Description
hhmmss.sss UTC time UTC time in hhmmss.sss format (000000.000 ~ 235959.999)
x Status Status
‘V’ = Navigation receiver warning
‘A’ = Data Valid
llll.lll Latitude Latitude in dddmm.mmmm format Leading zeros transmitted
a N/S indicator Latitude hemisphere indicator
‘N’ = North
‘S’ = South
yyyyy.yyy Longitude Longitude in dddmm.mmmm format Leading zeros transmitted
a E/W Indicator Longitude hemisphere indicator
'E' = East
'W' = West
x.x Speed over ground Speed over ground in knots (000.0 ~ 999.9)
u.u Course over ground Course over ground in degrees (000.0 ~ 359.9)
xxxxxx UTC Date UTC date of position fix, ddmmyy format
v Mode indicator Mode indicator
‘N’ = Data not valid
‘A’ = Autonomous mode
‘D’ = Differential mode
‘E’ = Estimated (dead reckoning) mode
‘M’ = Manual input mode
‘S’ = Simulator mode
hh Checksum  

The GPS/GLONASS receiver uses talker identifier GN for the RMC messages to indicate that it is operating in the combined GPS/GLONASS mode..
VTG – Course Over Ground and Ground Speed
The Actual course and speed relative to the ground.
Format::
$--VTG,x.x,T,,M,v.v,N,u.u,K,m*hh<CR><LF>

Field Name Description
x.x Course True course over ground in degrees (000.0 ~ 359.9)
v.v Speed Speed over ground in knots (000.0 ~ 999.9)
u.u Speed Speed over ground in kilometers per hour (0000.0 ~ 1800.0)
m Mode Mode indicator
‘N’ = not valid
‘A’ = Autonomous mode
‘D’ = Differential mode
‘E’ = Estimated (dead reckoning) mode
‘M’ = Manual input mode
‘S’ = Simulator mode
hh Checksum  

The GPS/GLONASS receiver uses talker identifier GN for the VTG messages to indicate that it is operating in the combined GPS/GLONASS mode.
In the following examples, we illustrate the use of GNS/GSA/GSV messages for different satellite constellations.
Examples::
Case 1: Only GPS satellites are available for the navigation solution.
$GNGNS,083613.333,2447.0963,N,12100.5393,E,AN,07,1.6,138.8,19.6,,0000*60 $GPGSA,A,3,03,19,24,08,20,32,28,,,,,,2.7,1.0,2.5*23 $GPGSV,3,1,12,11,82,240,20,07,62,241,21,08,45,304,28,19,35,038,31*72 $GLGSV,1,1,01,75,67,268,25,,,,,,,,,,,,*B3 (this sentence is present if GLONASS satellites are tracked by the receiver)
Case 2: Only GLONASS satellites are available for the navigation solution.
$GNGNS,083613.333,2447.0963,N,12100.5393,E,NA,04,1.6,138.8,19.6,,0000*60 $GLGSA,A,3,71,72,87,86,,,,,,,,,2.7,1.0,2.5*25
$GPGSV,1,1,1,11,82,240,20,,,,,,,,,,,,*2A (this sentence is present if GPS satellites are tracked by the receiver) $GLGSV,2,1,05,71,73,268,38,72,45,279,37,87,42,000,33,86,36,287,35*65 $GLGSV,2,2,05,74,39,268,28,,,,,,,,,,,,*34
Case 3: Both GPS and GLONASS satellites are available for the navigation solution.
$GNGNS,083613.333,2447.0963,N,12100.5393,E,AA,08,1.6,138.8,19.6,,0000*60 $GNGSA,A,3,03,19,24,08,20,32,,,,,,,2.7,1.0,2.5*23
$GNGSA,A,3,87,72,,,,,,,,,,,2.7,1.0,2.5*25 $GPGSV,3,1,7,03,82,240,41,19,62,241,40,24,45,304,39,08,35,038,38*72 $GPGSV,3,2,7,20,35,143,38,32,51,221,37,02,04,135,27,,,,*72 $GLGSV,1,1,03,87,73,268,38,72,42,041,36,65,36,287,,,,,*78
Summary:
The supported NMEA messages of GlonassCentral GPS/GLONASS receiver and the meaning are summarized in the following list.

NMEA message with the talker identifier Meaning
GPGGA The fix data from GPS/GLONASS receiver.
GNGNS The fix data from GPS/GLONASS receiver.
GPGSA The information of the satellites used in GPS-only navigation solution
GLGSA The information of the satellites used in GLONASS-only navigation solution
GNGSA Navigation solution based on combined satellite systems is provided. Two sentences are output for every navigation epoch. The first and the second sentence provide information about GPS and GLONASS satellites which are used in the navigation solution, respectively.
GPGSV The information of the GPS satellites in view of the receiver.
GLGSV The information of the GLONASS satellites in view of the receiver.
GNRMC Time, date, position, course and speed information for GPS/GLONASS receiver.
GNVTG Course and speed information relative to the ground for GPS/GLONASS receiver.
ORDERING INFORMATION
Model Name Description
NDV4554 GLONASS/GPS Receiver Module
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