KVH Industries DSP-3000 User manual

DSP-3000
KVH®DSP-3000
Fiber Optic Gyro
Technical Manual

DSP-3000 Fiber Optic Gyro
Technical Manual
This manual provides detailed guidelines for the proper installation
and operation of the KVH DSP-3000 fiber optic gyro (FOG).
Throughout this manual, important information is marked for your
attention by these icons:
A helpful tip that either directs you to
a related area within the manual or
offers suggestions on getting the
highest quality out of your system.
An alert to important information
regarding procedures, product
specifications, or product use.
An electrical safety warning to help
identify electrical issues that can be a
hazard to either this KVH product or
a user.
Information about installation,
maintenance, troubleshooting, or
other mechanical issues.
Please direct questions, comments, or suggestions to:
KVH Industries, Inc.
50 Enterprise Center
Middletown, RI 02842-5279 USA
Tel: [phone]
Fax: [phone]
If you have any comments regarding this manual, please e-mail
them to [email protected]. Your input is greatly appreciated!
KVH Part # 54-0215 Rev. C
© 2005-2007 KVH Industries, Inc. All rights reserved.
Protected by U.S. and foreign patents

KVH®is a registered trademark of KVH Industries, Inc.

54-0215 Rev. C i
Table of Contents
1Introduction ........................................................... 1
1.1 Scope of this Manual.....................................................................1
1.2 Product Description ......................................................................1
1.2.1 Output Orientation ...............................................................5
1.2.2 Interface Connector .............................................................5
2Digital 100 Hz Asynchronous Interface............................ 7
2.1 Description ...................................................................................7
2.1.1 User Commands..................................................................8
2.2 Wiring the Gyro for Digital Asynchronous Operation ................9
2.2.1 Wiring Guidelines ................................................................9
2.3 Preliminary Testing .....................................................................10
2.3.1 Test Procedure ..................................................................10
3Digital 1000 Hz Asynchronous Interface .........................12
3.1 Description .................................................................................12
3.1.1 Message Structure ............................................................13
3.1.2 Message Content ..............................................................13
3.1.3 Message Rates..................................................................14
3.1.4 Synchronization .................................................................14
3.2 Wiring the Gyro for Digital Asynchronous Operation ..............15
3.2.1 Wiring Guidelines ..............................................................15
3.3 Preliminary Testing .....................................................................16
3.3.1 Test Procedure ..................................................................16
4Digital 1000 Hz Synchronous Interface...........................18
4.1 Description .................................................................................18
4.1.1 Message Structure ............................................................19
4.1.2 Message Content ..............................................................20
4.1.3 Message Rates..................................................................20

ii 54-0215 Rev. C
4.2 Wiring the Gyro for Digital Synchronous Operation ................21
4.2.1 Wiring Guidelines ..............................................................21
4.3 Preliminary Testing .....................................................................22
4.3.1 Test Procedure..................................................................22
5Analog Interface .................................................... 24
5.1 Description .................................................................................24
5.1.1 Analog Output Voltage Generation.................................... 24
5.1.2 Rate Scaling ......................................................................24
5.2 Wiring the Gyro for Analog Operation.......................................25
5.2.1 Wiring Guidelines ..............................................................25
5.3 Preliminary Testing .....................................................................27
5.3.1 Test Procedure..................................................................27
6Mounting the Gyro .................................................. 28
7Troubleshooting..................................................... 29
Appendix A Patent Protection*......................................... 30

54-0215 Rev. C 1
1 Introduction
1.1 Scope of this Manual
This technical manual supports KVH Industries’ DSP-3000 series fiber optic gyros with
digital or analog output. Technical and performance specifications, interfaces, installation
and testing guidelines, and a brief troubleshooting guide are included. This manual covers
the DSP-3000 model gyros with the following part numbers:
Table 1: Gyro Part Numbers
Part No. Output
02-1222-01 Digital, 100 Hz asynchronous
02-1222-02 Digital, 1000 Hz synchronous
02-1222-03 Analog
02-1222-04 Digital, 1000 Hz master synchronous
02-1222-07 Digital, 1000 Hz asynchronous
1.2 Product Description
The DSP-3000 is a single-axis interferometric fiber optic gyro for use in a wide range of
applications, including antenna and optical stabilization, navigation, positioning,
aerospace (AHRS), IMUs, robotics, and instrumentation. Based on proprietary
polarization-maintaining fiber and precision FOG technology, the DSP-3000 employs a
digital signal processor and an all-fiber, open loop optical circuit. The gyro measures
angular rate of rotation, which can be integrated to allow turning angle to be measured
accurately. Operating from a nominal 5 VDC, it outputs a digital or analog message with
input rates of up to ±375 degrees per second for digital versions, or ±100 degrees per
second for the analog version. The DSP-3000 is self-initializing and ready for use
approximately 5 seconds after power is applied.

2 54-0215 Rev. C
Product specifications are listed in Table 2. Please read the entire manual prior to making
connections between the unit and your system.
Table 2: Product Specifications
Attribute Rating
Performance
Digital Analog
Maximum Input Rate ±375°/sec ±100°/sec
Scale Factor
1000 ppm, 1σof full scale,
for ±375°/sec
Linearity (room temp)
500 ppm, 1σof full scale,
for ±150°/sec
500 ppm, 1σof full scale
Temperature Sensitivity 500 ppm, 1σ500 ppm, 1σ
Error (full rate & temp) 1500 ppm, 1σ1000 ppm, 1σ
Bias
Offset (room temp) ±20°/hr ±100°/hr
Stability (room temp)* 1°/hr, 1σ3°/hr, 1σ
Temperature Sensitivity
(<1°C/min)
6°/hr, 1σ20°/hr, 1σ
>40 Hz,
100 Hz asynchronous
Bandwidth (3 dB)
>400 Hz,
1000 Hz synchronous or
asynchronous
100 Hz
100/sec,
100 Hz asynchronous
Update Rate
1000/sec,
1000 Hz synchronous or
asynchronous
2000/sec
Angle Random Walk (noise)* 4°/hr/√Hz
0.0667°/√hr
6°/hr/√Hz
0.1°/√hr
Initialization Time (valid data) <5 sec
* Bias Stability and Angle Random Walk determined by Allan variance method.

54-0215 Rev. C 3
Table 2: Product Specifications (Continued)
Attribute Rating
Electrical
Digital Analog
Input Voltage +5 VDC ±10%
Power Consumption 3 watts maximum (2 watts typical)
Output
38,400 Baud (RS-232),
100 Hz asynchronous
±2 VDC full scale,
differential
115,200 Baud (RS-232),
1000 Hz asynchronous
Type
3.072 MHz serial,
1000 Hz synchronous
±1 VDC full scale,
single-ended
Format (selectable) Rate, Incremental Angle, or
Integrated Angle
Rate
Physical
Dimensions 3.5" x 2.3" x 1.3"
(88.9 mm x 58.42 mm x 33.02 mm)
Weight 0.6 lbs (0.27 kg)
Environmental
Operating Temperature -40°F to +167°F (-40°C to +75°C)
Storage Temperature -58°F to +185°F (-50°C to +85°C)
Shock (functional) Functional sawtooth 40 g, 6-10 msec
Random Vibration 20 to 2000 Hz, 8 g rms, operational
MTBF >55,000 hours, ground mobile
In all cases while operating, input rate must not exceed ±500°/second. If
the input rate exceeds ±500°/second, physical damage will not occur but
the output data will become unreliable, regardless of the validity BIT.

4 54-0215 Rev. C
An interface control drawing (ICD) illustrating the dimensions, connector placement, and
mounting holes is provided in Figure 1.
All dimensions are shown in inches [millimeters] format.
Figure 1: Interface Control Drawing

54-0215 Rev. C 5
1.2.1 Output Orientation
The DSP-3000 senses rotation on an axis perpendicular to the plane of the baseplate. An
arrow on the product’s serial number label (located on the side of the unit) shows the
rotational direction corresponding to a positive output. Looking at the gyro from overhead,
a clockwise rotation will produce a positive output.
Figure 2: Clockwise Rotation
To minimize output errors and cross-coupling to the sensitive axis of the gyro, the
mounting surface should be parallel to the plane normal to the rotational axis. If this
alignment is not observed, the output data will vary as a function of the cosine of the
misalignment angle.
1.2.2 Interface Connector
The DSP-3000 is equipped with a 15-pin interface connector of the following type: Tyco
Electronics’ single-row Dualobe connector (Tyco part number SSM015L2HN). With the
connector positioned at the top of the gyro wall (as shown in Figure 1), pin 1 is located on
the right side when viewing the connector head-on. Figure 3 shows the gyro interface
connector pins, and Table 3 on the following page lists the function of each pin.
Figure 3: Gyro Connector Pins (Head-on View)
Pin 1Pin 15

6 54-0215 Rev. C
Table 3: Gyro Connector Pin-outs
Pin Function Type Characteristics
1 +5 V PWR Power Positive +5 VDC supply
2 +5 V RTN Power Return Ground
3 Chassis Gnd Shield Ground
4 Rate + Analog Differential with Rate -
5 Rate - Analog Differential with Rate +
6 Analog Gnd Ground Ground Reference for Rate + / Rate -
7 Spare - Reserved for Future Use
8 BIT TTL Built In Test (High Indicates Fault)
9 Tx RS-232 Async Serial Transmit Line
10 Rx RS-232 Async Serial Receive Line
11 Gnd TTL Digital Ground
12 Tclk TTL Sync Serial Port Transmit Clock
13 Tdata TTL Sync Serial Port Transmit Data
14 Tsync TTL Sync Serial Port Transmit Frame Sync
15 Msync TTL Sync Serial Port Receive Frame Sync
For a suitable mating connector, use Tyco Electronics’ single-row Dualobe plug assembly
with flying leads (Tyco part number SSL015PC2DCXXXN, where XXX is length in
inches). This mating connector, with 12" leads, is available from KVH (KVH part
number 32-0780).
The next three sections explain the different interface options:
•Digital 100 Hz Asynchronous: see page 7
•Digital 1000 Hz Asynchronous: see page 12
•Digital 1000 Hz Synchronous: see page 18
•Analog: see page 24

54-0215 Rev. C 7
2 Digital 100 Hz Asynchronous Interface
2.1 Description (KVH Part No. 02-1222-01)
Connector pins 9 (transmit) and 10 (receive), with ground pin 11, provide an
asynchronous serial interface to the gyro. This interface has the following characteristics:
Type: RS-232
Baud Rate: 38,400 Baud
Parity: None
Data Bits: 8
Stop Bits: 1
Flow Control: None
Both transmit and receive functions are available with this interface. Since transmit (Tx)
and receive (Rx) designations refer to the gyro as the source, “transmit” is an output from
the gyro, and “receive” is an input to the gyro. The “transmit” output has the following
format:
Output Burst Rate: 100/second (approximate, see Note 1)
Output Format: ASCII text consisting of two decimal data words (separated by a
space), followed by a carriage return/line feed sequence:
(-)xxx.xxxxxx y
(-)xxx.xxxxxx = Data Word 1
y= Data Word 2
Output Data Word 1: Three user-selectable formats:
Rate (in degrees/second) = the average over the interval from the
last output; this is the default mode at power-up
Incremental Angle (in degrees) = the angular change from the
last output
Integrated Angle (in degrees) = the rotation angle modulo 360
from an arbitrarily user-chosen zero reference (see “Z” on the
following page)
Output Data Word 2: BIT; ASCII 1 = “Data Valid,” ASCII 0 = “Fault”
Note 1: The output burst rate may vary, gyro-to-gyro, by ±2 to ±3 percent. There is also a variation over
temperature of approximately ±0.2 percent.
The “receive” input supports several user commands. The next section explains how to
access the maintenance mode and lists the available configuration commands.

8 54-0215 Rev. C
2.1.1 User Commands
The following single-character user commands to the gyro are supported:
Table 4: Single-character User Commands
Command Function
R Switch output to Rate
A Switch output to Incremental Angle
P Switch output to Integrated Angle
Z Zero the Integrated Angle value
These single ASCII characters are input without a carriage return or line feed. A command
may need to be sent more than once for the command to execute.

54-0215 Rev. C 9
2.2 Wiring the Gyro for Digital Asynchronous Operation
Use the wiring diagram below as a guide to connect the gyro to your application.
Figure 4: Wiring Diagram
(Asynchronous Operation)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1
2
3
4
5
6
7
8
9
5 VDC
RETURN
DC SUPPLY
COMPUTER
COM PORT
RX
TX
SIG GND
+5 VDC
POWER COMMON
RX
TX
CASE GROUND
SIGNAL COMMON
2.2.1 Wiring Guidelines
Be sure to follow the guideline below to ensure optimum performance.
•The chassis ground, pin 3, as well as the housing, should be coupled to the system
ground with minimum impedance. The surface on which the gyro is mounted
should not inject AC noise onto the gyro housing as it will radiate into the gyro
electronics.

10 54-0215 Rev. C
2.3 Preliminary Testing
Before connecting and mounting the gyro to your system, a simple familiarization test is
suggested if this is your first introduction to the product. This test will also verify proper
unit operation and assist in troubleshooting.
Equipment needed to test the gyro:
•+5 VDC power supply
•Computer with an RS-232 input and a terminal emulation program
(such as Windows Hyperterminal)
•Interface cable with a female 15-pin single-row Dualobe connector on
one end and a DB9 connector on the other end, wired as shown in
Figure 4 on page 9
2.3.1 Test Procedure
Follow the steps below to test the gyro for proper operation.
1. Place the DSP-3000 module on a flat surface with the mounting surface down.
2. Connect the +5 VDC (±10%) power supply positive to pin 1; connect the negative
to pins 2 and 3.
3. Connect the DB9 plug from the test cable harness to the computer’s COM port.
Select the serial port (to which the cable was connected), open the test data
acquisition program, and select the following communications program settings:
•38,400 baud
•8 data bits
•1 stop bit
•no parity
•no flow control
4. With the gyro held stationary, the indicated mean (30-second average) input rate
should be less than 0.005°/s, excluding Earth rate. If no data is received, check the
wiring for proper data line connection.
To calculate the Earth rate for your geographical area, use the following
formula:
Earth rate = -15.04107 x sin(latitude)
Note: Northern latitudes are positive and southern latitudes are negative.

54-0215 Rev. C 11
5. Grasp the gyro and slowly rotate it in the direction of the arrow on its serial
number label. The output data should indicate a positive change.
6. Slowly rotate the gyro in the opposite direction. The output data should indicate a
negative change.
7. After the initial 5-second startup, the BIT data word (Data Word 2) should show
ASCII 1 (“data valid”) at all times. If the BIT shows ASCII 0 (“fault”), the gyro
has malfunctioned.

12 54-0215 Rev. C
3 Digital 1000 Hz Asynchronous Interface
3.1 Description (KVH Part No. 02-1222-07)
Connector pin 9, with ground pin 11, provides an asynchronous serial interface to the
gyro. This interface has the following characteristics:
Type: RS-232
Baud Rate: 115,200 Baud
Parity: None
Data Bits: 8
Stop Bits: 1
Flow Control: None
The gyro’s output has the following format:
Output Burst Rate: 1000/second (approximate, see Note 1)
Output Format: Each character contains 10 bits:
•1 start bit (Space, binary 0)
•8 data bits (1 message byte, starting with LSB)
•1 stop bit (Mark, binary 1)
An idle line is always marking, that is, in a binary 1 state. Four
characters in sequence constitute a basic message.
Note 1: The output burst rate may vary, gyro-to-gyro, by ±2 to ±3 percent. There is also a variation over
temperature of approximately ±0.2 percent.

54-0215 Rev. C 13
3.1.1 Message Structure
A basic message is 32 bits (4 bytes) long. The most significant byte (MSB) is sent first.
Table 5 and Figure 5 define the bits in the message.
Table 5: Message Bits
Bit(s) Usage Values
31 Message Validity 0 = Hardware BIT signal is low or contents are invalid
1 = Hardware BIT OK and contents are valid
30, 29 Synchronization See Section 3.1.4, “Synchronization”
28, 27 Type 0 = Rate data
1 = Incremental Angle data
2 = Integrated Angle data
26 Parity See Note 1
25 - 0 Content See Section 3.1.2, “Message Content”
Note 1: Preset Bit 26 to 1, then compute Bit 26 = Bit 0 ⊕Bit 1 ⊕Bit 2…⊕Bit 25 ⊕Bit 26 ⊕
Bit 27 ⊕Bit 28 ⊕Bit 29 ⊕Bit 30 ⊕Bit 31.
Figure 5: Message Structure
3.1.2 Message Content
Use of the 26-bit Content field depends on the Type bits, as noted below.
Rate Data
When the Type bits indicate Rate Data, the contents are in two’s complement format. The
LSB represents 60 µ°/s, or 0.216°/hr.
Incremental Angle Data
When the Type bits indicate Incremental Angle Data, the contents are in two’s
complement format. The LSB represents 6 µ°.
Byte 1 Byte 2 Byte 3 Byte 4
24 31 16 23 8 15 0 7
Validity
Sync
Type
Parity
Content
= Start Bit = Stop Bit
Content
Note: In asynchronous protocol, the
least significant bit (LSB) is sent first.

14 54-0215 Rev. C
Integrated Angle Data
When the Type bits indicate Integrated Angle data, the contents can be interpreted based
on the table below.
Table 6: Message Contents (Type Bits = Integrated Angle Data)
Bit(s) Usage Values
25, 24, 23 360°modulo counter Increment when crossing from 359 to 0.
Decrement when crossing from 0 to 359.
Bit 25 is MSB; Power-up value is 0.
22 - 0 0 <= integrated angle < 360 LSB (bit 0) value is 42.91534 µ°.
3.1.3 Message Rates
The rate at which the Rate or Integrated Angle information actually updates depends on
the application. Standard rate is 1000 Hz.
3.1.4 Synchronization
Message bits 29 and 30 make up the synchronization field for each message. These bits
conform to an eight-bit, continuously repeating pattern, as shown below.
1st Message 00
2nd Message 01
3rd Message 10
4th Message 11
This synchronization pattern allows you to design a receiver algorithm that can detect the
first byte of a message. For example, you could create a “state machine” with two modes:
Acquisition and Locked. In Acquisition mode, the state machine would examine the sixth
and seventh bits of each byte. Once it finds a byte position that exhibits the defined
synchronization pattern for 10 cycles in a row, and no other byte position has exhibited the
pattern for more than 3 of the last 10 cycles, the state machine would designate that byte
position as the first byte in the four-byte message. The state machine would then enter
Locked mode. In Locked mode, the state machine would continue to monitor each byte. If
the byte position that it designated as “first” does not match the synchronization pattern
for more than 3 out of 10 cycles, and a different byte position matches 7 or more, the state
machine would then designate the different byte position as the first byte.

54-0215 Rev. C 15
3.2 Wiring the Gyro for Digital Asynchronous Operation
Use the wiring diagram below as a guide to connect the gyro to your application.
Figure 6: Wiring Diagram
(Asynchronous Operation)
3.2.1 Wiring Guidelines
Be sure to follow the guideline below to ensure optimum performance.
•The chassis ground, pin 3, as well as the housing, should be coupled to the system
ground with minimum impedance. The surface on which the gyro is mounted
should not inject AC noise onto the gyro housing as it will radiate into the gyro
electronics.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1
2
3
4
5
6
7
8
9
5 VDC
RETURN
DC SUPPLY
COMPUTER
COM PORT
RX
SIG GND
+5 VDC
POWER COMMON
TX
CASE GROUND
SIGNAL COMMON