Ublox C93-M8E User manual

C93-M8E
Application Board
User Guide

Abstract
This document describes the structure and use of the C93-
M8E application board and provides
information for evaluating and testing u-
blox M8 Untethered Dead Reckoning (UDR) positioning
technology.
www.u-blox.com
UBX-15031067 - R03

C93-M8E - User Guide
UBX-15031067 - R03 Page 2 of 21
Early Production Information
Document Information
Title C93-M8E
Subtitle User Guide
Document type User Guide
Document number UBX-15031067
Revision and date R03 12-Dec-2018
Disclosure Restriction Early Production Information
This document applies to the following products:
Product name Type number ROM/FLASH version PCN reference
C93-M8E C93-M8E-0-00 ROM 3.01 / Flash FW 3.01 UDR 1.21 N/A
u-blox or third parties may hold intellectual property rights in the products, names, logos and designs included in this
document. Copying, reproduction, mod
ification or disclosure to third parties of this document or any part thereof is only
permitted with the express written permission of u
-blox.
The information contained herein is provided “as is” and u
-blox assumes no liability for its use. No warranty, either express or
implied, is given, including but not limited
to, with respect to the accuracy, correctness, reliability and fitness for a particular
purpose of the information. This document may be revised by u
-blox at any time without notice. For the most recent
documents, visit www.u
-blox.com.
Copyright © u
-blox AG.

C93-M8E - User Guide
UBX-15031067 - R03 Page 3 of 21
Early Production Information
Contents
Document Information................................................................................................................................2
Contents ..........................................................................................................................................................3
1Product description ..............................................................................................................................4
1.1 Overview........................................................................................................................................................4
1.2 C93-M8E package includes ...................................................................................................................... 4
1.3 Evaluation software....................................................................................................................................4
1.4 System requirements ................................................................................................................................ 4
2Specifications .........................................................................................................................................5
3Device description.................................................................................................................................6
3.1 Interface connection and measurement................................................................................................ 6
3.2 Integrated GNSS antenna.........................................................................................................................6
3.3 Evaluation unit.............................................................................................................................................6
3.3.1 USB ........................................................................................................................................................ 6
3.3.2 Pin header............................................................................................................................................. 7
3.3.3 LED.........................................................................................................................................................7
3.3.4 Backup Battery....................................................................................................................................7
3.3.5 GNSS Configuration........................................................................................................................... 7
4Setting up.................................................................................................................................................8
4.1 C93-M8E installation ................................................................................................................................. 8
4.1.1 Mounting the C93-M8E.....................................................................................................................8
4.1.2 Connecting the cables .......................................................................................................................8
4.2Recommended Configuration ..................................................................................................................9
4.2.1 Serial port default configuration .....................................................................................................9
4.2.2 UDR Receiver Operation .................................................................................................................... 9
4.3 Accelerated Initialization and Calibration Procedure ........................................................................11
5Test Drives............................................................................................................................................. 12
6Block diagram ....................................................................................................................................... 13
7Board layout........................................................................................................................................... 14
8Schematic .............................................................................................................................................. 16
9Troubleshooting................................................................................................................................... 17
10 Common evaluation pitfalls ............................................................................................................. 19
Related documents ................................................................................................................................... 20
Revision history.......................................................................................................................................... 20
Contact........................................................................................................................................................... 21

C93-M8E - User Guide
UBX-15031067 - R03 Early Production Information Product description
Page 4 of 21
1Product description
1.1 Overview
Based on the EVA-M8E module, the C93-M8E application board enables immediate evaluation of u-
blox’s Untethered Dead Reckoning (UDR) technology in most vehicle applications. The C93-M8E
includes the antenna, RTC and peripheral components that are required to complete an end-product
design, all enclosed in a small case, ready for mounting in a vehicle application. The built-in USB
interface provides both power supply and high-speed data transfer, and eliminates the need for an
external power supply. The C93-M8E is compact, and ideally suited for use in laboratories and
vehicles. It can be used directly with a PDA or a notebook PC via its USB interface. Schematics and
layouts are available, allowing the C93-M8E to be used as a basis for customer designs.
1.2 C93-M8E package includes
•C93-M8E Application board in clear plastic housing
•USB cable
1.3 Evaluation software
The u-center software installation package for the C93-M8E can be downloaded from the Web:
www.u-blox.com/en/evaluation-software-and-tools. Once the zip file is downloaded and unzipped,
unzip the file in Tools folder and double-click the extracted exe file. The software will be installed on
your system and placed under the “u-blox” folder in the “Start Programs” menu.
The installation software includes u-center, an interactive tool for configuration, testing,
visualization and data analysis of GNSS receivers. It provides useful assistance during all phases of
a system integration project. The version of the u-center should be v8.22 Beta03 or later.
1.4 System requirements
•PC with USB interface
•Operating system: Windows Vista onwards (x86 and x64 versions)
•USB drivers are provided in the installed software

C93-M8E - User Guide
UBX-15031067 - R03 Early Production Information Specifications
Page 5 of 21
2Specifications
Parameter Specification
USB 1 micro USB V2.0
Extra connectors connection pins for UART communication, 3.3 V
Dimensions 49 x 49 x 20 mm
Power Supply 5V via USB or external powered via extra power supply pin 1 (VCC) and common
supply/interface ground pin 6 (GND)
Normal Operating temperature -40°C to +65°C
Table 1: C93-M8E specifications

C93-M8E - User Guide
UBX-15031067 - R03 Early Production Information Device description
Page 6 of 21
3Device description
3.1 Interface connection and measurement
For connecting the application board to a PC, use included USB cable or 6-pin connector. USB
provides both power and a communication channel.
Figure 1: Connecting the unit for power supply and communication
3.2 Integrated GNSS antenna
The C93-M8E includes an 18 mm patch type GNSS antenna. The PCB design allows for patch
antennas of up to 25 mm to be fitted (soldering required).
3.3 Evaluation unit
Figure 2 shows C93-M8E application board.
Figure 2: C93-M8E application board
3.3.1 USB

C93-M8E - User Guide
UBX-15031067 - R03 Early Production Information Device description
Page 7 of 21
A micro USB V2.0 compatible port is featured for data communication and power supply.
3.3.2 Pin header
The C93-M8E application board includes a 6-pin latching connector from the TE Connectivity
AMPMODU MTE series. Mating cable receptacles from this series include part numbers 5-103960-
5 and 5-103957-5. The 6-pin header is assigned as listed in Table 2:
Pin Nr. Assignment
1 VCC
2 TXD, GPS Transmit Data, serial data to DTE, 3V logic level inverted
3 RXD, GPS Receive Data, serial data from DTE, 3V logic level inverted
4 Connect to RESET pin of EVA-M8E
5 Connect to SAFEBOOT pin of EVA-M8E
6 GND
Table 2: pin header description for C93-M8E
☞Note that the UART signals are at 3 V logic levels, suitable only for direct connection to a host
microcontroller. For connection to standard RS-232 level interfaces on PCs or other equipment,
a separate inverting level-shifter buffer must be used (e.g. MAX3232).
3.3.3 LED
On the front panel of the unit, a single blue LED may be configured to follow the receiver time pulse
signal using message UBX-CFG-TP5. The time-pulse may be configured so that the LED starts
flashing at one pulse per second during a valid GNSS fix. If there is no GNSS fix, the LED will only light,
without flashing. The time pulse is enabled by default in C93-M8E.
3.3.4 Backup Battery
The unit includes a “Supercapacitor” type rechargeable backup battery. This is necessary to store
calibration, dead-reckoning and orbital information between operations, and supports the Real Time
Clock (RTC) to enable immediate start-up in DR mode and fast acquisition of GNSS signals. Once
fully charged, the capacitor provides around 24 hours backup supply.
3.3.5 GNSS Configuration
The C93-M8E supports GPS, QZSS, GLONASS, Galileo and BeiDou.
The GNSS to be used can be configured on u-center (View Messages View then UBX-CFG-GNSS).
For more information, refer to the
u-center User Guide [6], the u-blox 8 / u-blox M8 Receiver
Description including Protocol Specification
[5].

C93-M8E - User Guide
UBX-15031067 - R03 Early Production Information Setting up
Page 8 of 21
4Setting up
4.1 C93-M8E installation
The following sections describe the steps required to complete the C93-M8E hardware installation.
4.1.1 Mounting the C93-M8E
The C93-M8E application board should be firmly attached to the car body so as to avoid any
movement or vibration with respect to the car body. The application board should not be attached to
any “live” (unsprung) part of the vehicle’s suspension. Often it is enough to use strong double sided
tape or Velcro tape glued to the bottom of the C93-M8E casing. The C93-M8E must be secured
against any change in position and particularly orientation with respect to the vehicle frame.
Figure 3: Example installation of the C93-M8E on car dashboard
☞For best performance, the integrated antenna needs to have the best sky view possible in the car
or outside of the car.
4.1.2 Connecting the cables
Rather than using USB alone, we recommend using the 6-pin latching receptacle recommended
above, because it locks securely to the front connector of the C93-M8E. Other 0.1" receptacles may
be compatible. You will need to solder the necessary I/O cables to signal sources and outputs as in
Table 3.
1. Connect the unit to a PC running Microsoft Windows by
1.1. USB: Connect via USB port or
1.2. UART: Connect via 6-pin header via an inverting RS-232 level shifter (e.g. MAX3232).
2. The device is powered either via USB or from a 5 V supply via Pin #1 of the 6-pin header.
3. Start the u-center GNSS Evaluation Software and select the corresponding COM port and baud
rate.
☞Refer to the u-center User Guide [6] for more information.

C93-M8E - User Guide
UBX-15031067 - R03 Early Production Information Setting up
Page 9 of 21
4.2 Recommended Configuration
For an optimum navigation performance, the recommended configuration is as follows:
•Navigation Rate: The default DR/GNSS-fused navigation solution update rate of 1 Hz is
recommended. You can set the navigation update rate with the message UBX-CFG-RATE. (In this
mode navigation rates up to 20 Hz are also available from the UBX-HNR-PVT message.)
•Signal Attenuation Compensation: For installations where the signals are attenuated due to the
C93-M8E placement, the signal attenuation compensation feature can be used to restore normal
performance. There are three possible modes:
oDisabled: no signal attenuation compensation is performed
oAutomatic: the receiver automatically estimates and compensates for the signal attenuation
oConfigured: the receiver compensates for the signal attenuation based on a configured value
•These modes can be selected using UBX-CFG-NAVX5 message.
☞In the case of the "configured" mode, the user should input the maximum C/N0 observed in a
clear-sky environment, excluding any outliers or unusually high values. The configured value can
have a large impact on the receiver performance, so should be chosen carefully.
☞For more information, refer to the u-blox 8 / u-blox M8 Receiver Description including Protocol
Specification
[5].
4.2.1 Serial port default configuration
Parameter Description Remark
UART Port 1, Input UBX and NMEA protocol at 9,600 Bd
UART Port 1, Output UBX and NMEA protocol at 9,600 Bd Only NMEA messages are activated
USB, Input UBX and NMEA protocol
USB, Output UBX and NMEA protocol Only NMEA messages are activated
Table 3: Default configuration
4.2.2 UDR Receiver Operation
By default, C93-M8E is ready to operate in UDR navigation mode.
☞The statuses of different modes of UDR receiver are output in the UBX-ESF-STATUS message.
4.2.2.1 Initialization Mode
The purpose of the Initialization phase is to estimate all unknown parameters that are required for
achieving fusion. In this case, the required sensor calibration status shows NOT CALIBRATED (see
Figure 4). Note that the initialization phase requires good GNSS signals conditions as well as periods
during which vehicle is stationary and moving (including turns). Once all required initialization steps
are achieved, fusion mode is triggered and the calibration phase begins.

C93-M8E - User Guide
UBX-15031067 - R03 Early Production Information Setting up
Page 10 of 21
Figure 4: Screenshot of u-center showing the INITIALIZING mode in UBX-ESF-STATUS message
4.2.2.2 Fusion Mode
Once the initialization phase is achieved, the receiver enters navigation mode and starts to compute
combined GNSS/Dead-reckoning fixes and to calibrate the sensor required for computing the fused
navigation solution. The sensor calibration status outputs CALIBRATING (see Figure 5).
Figure 5: Screenshot of u-center showing the FUSION mode in UBX-ESF-STATUS message
As soon as the calibration reaches a status where optimal fusion performance can be expected, the
sensor calibration status are flagged as CALIBRATED (see Figure 6)