Digital Radar Processing and the New Low Power Radars

Navico BR24 Radar
Odin Sletten
Technical Sales Engineer
Navico Denmark

© Navico Company Confidential
2
A Short History of Radar
In 1917, Nikola Tesla first established the principles for primitive radar units
In 1935, The British invented and patented the first radar for aircraft defence
In 1950, Decca introduced the first marine pulse radar utilising a magnetron, which eventually trickled down into recreational boats…

3
60 Years of Development

4
Weaknesses of Traditional Radar
User expertise required
Blurs and distorts objects, making it difficult to interpret surroundings and navigate safely
Obscures objects closest to the boat, where visibility is most important for collision avoidance
Difficulty distinguishing targets from clutter - requires experience to safely operate
Inconvenient installation and operation
Magnetron takes several inconvenient minutes to warm up
Magnetron has a limited life, and is expensive to replace
Large cables and connectors
Power consumption is impractical for small boats and most sailboats
Emissions require mounting away from humans and other electronic equipment. Most small boats have no room at all

5
First X-band Radome Radar

6
Navico’s BroadBand Radar
“Revolutionary improvement in situational awareness” - the best short-range resolution and target discrimination of any X-band marine radar
Radar is finally easy enough for a novice – identifies targets clearly with no ‘tune control’, as sea and rain clutter rejection is 5-10 times better than a pulse radar
Navigation is truly easy, even at an unprecedented 1/32 NM range, with unparalleled resolution and clarity within two metres of the dome, with no ‘main bang’, ‘zero range adjust’, or close-range sidelobe distortion

7
Close Range Performance

8
Comparison and Main bang
main
bang
4 kW HD pulse radar, 1/8 NM range
BroadBand Radar, 1/16 NM range

9
Comparison and Main bang
main bang
suppression
4 kW HD pulse radar, 1/8 NM range
Broadband Radar, 1/16 NM range

10

11
Approximate position
of boat
Moored boat
Foot bridge
4 kW HD pulse radar
Broadband Radar

12
Superb Resolution
Pile moorings
Moored boat
4 kW HD Pulse Radar
BroadBand Radar

13
Seaclutter Performance
Two boats, towing into the harbour
4 kW HD pulse radar, 1/2nm
Sea clutter rejection 50%
BroadBand Radar ¼ NM
No sea clutter rejection applied

What makes the difference?

15
Traditional Radar
The radar transmits a powerful, but very short pulse, at a fixed frequency.
The pulse propagates outwards in a direction determined by the angle of the rotating radar antenna at the time of transmission.
The radar then switches to receive mode to listen for reflections.
If the pulse reflects off an object, it will return to the receiver with a delay proportional to the distance of the object from the transmitter.
The antenna angle at the time of pulse transmission equals the direction of the object.

16
Frequency
9.41GHz
9.4GHz
1ms
4ms
Time
BroadBand Radar
FMCW = Frequency Modulated Continuous Wave
Transmits a ‘rising tone’ (Tx wave) with linear increasing frequency
The wave propagates out from the transmitter retaining the frequency it had when it was transmitted
If it reflects off an object, it will return to the receiver, still at the frequency it had when originally transmitted
Meanwhile the transmitter continues to output an increasing frequency

17
Tx
Rx– retains same frequency it had when it was transmitted
Frequency
At any instant in time, Tx freq is higher than Rx freq
Time
Time delay
BroadBand Radar
Frequency Difference in Transmitted and Received Signals
The difference in the currently transmitted and currently received frequencies, coupled with the known rate of frequency increase, allows a time of flight to be calculated, from which we can calculate distance.

Unique Advantages

19
Solid State – No Magnetron
“Start faster, go longer” - 100% solid state RF design – no magnetron! Provides InstantOn™ power up and low power consumption
Eliminates 2-3 minutes warm-up time typical of magnetron pulse radars
Conserves power; operating power drain is ~30% less than the best 2 kW radar (<1/20 in standby mode) – extremely beneficial for sailboats and smaller power boats
No limit on transmit usage lifetime – typically 2-3,000 hours for a magnetron pulse radar

20
Two Antenna Arrays
RX
TX

21
Totally Safe
“Incredibly approachable” - Totally safe RF transmitted emissions and flexible installation setup allows you to mount the radome anywhere
Extremely low power - less than 1/10th of the transmitted emissions of a mobile phone; install in any position, even on the smallest of boats

22
Proven Safety
Safe Distance
Radar Type
Conclusion: Human exposure level to radiation outside the radome is 0.45 W/m2, well below the general public safety emission level of 10 W/m2. Included is the possible case of mechanical failure of the motor or drive belt with the antenna pointing into a fixed direction.
1,4 m (4.6 ft)
Standard 2 kW pulse radar
2,8 m (9.3 ft)
Standard 4 kW pulse radar
0 m (0 ft)
New Navico Broadband radar
Page 22

23
Easy Installation
“Incredibly approachable” - Totally safe RF transmit emissions and flexible installation setup allows you to mount the radome anywhere
Super small custom 13.5 mm RJ45 connector and round 9 mm pre-connected radar cable allows simple bridge tube installations

24
Radar Interface
Radar Interface Box
Fully watertight
Small RJ45 connector

25
Connector
Radar Dome Connection
External watertight connector
Same footprint as today’s 2 kW scanner

26
Mutltiple Displays
“Incredibly approachable” - Totally safe RF transmit emissions and flexible installation setup allows you to mount the radome anywhere
Super small custom 13.5 mm RJ45 connector and round 9 mm pre-connected radar cable allows simple bridge tube installations
Compatible with a wide range of Navico multifunction displays and heading sensors

27
Multiple Displays
NSE8
NSE12
HDS-7
HDS-7m
HDS-10
HDS-10m
HDS-5
HDS-5m
HDS-5x
HDS-8
HDS-8m
GB40
NX45 12”
NX40 8”

28
The Highlights
Super high resolution
No blind spot at center (mainbang)
Totally safe, 0.1 W TX – install anywhere
InstantOn – no warm up time
Lower power consumption, no standby power
Five times better sea and rain clutter performance
Easy to install – very small connector

29
The Differences Between Pulse and FMCW Radars
Summary from a Technical Briefing by Bill Mullarkey from Navigate-us.com
N.B This was purely from theoretical analysis, no practical testing was made

30
Long Range Performance

Scanner height
Target
Object at sea level
Small boat (2 m high)
Big launch (6 m high)

2 metres
3.1 miles
6.3 miles
8.5 miles
3 metres
3.8 miles
7.0 miles
9.2 miles
4 metres
4.4 miles
7.5 miles
9.8 miles
Maximum range for any radar under ideal circumstances:
__________________________________________________________________________
So….. there is no possible way a radar on a small/medium boat can see a large launch at more than 10 miles
But… It may be possible to see rain or high land features beyond 10 miles.

31
Further Enhancement
Navico’s R&D teams have developed technologies, which bring interference from other radar and onboard reflectors to a minimum or even totally eliminates them.
This also means we are not depending on already patented technologies, which would have influenced the price of the radar.

32
Power Requirements
Power consumption transmitting is only 17 W
30% less than a 2 kW radar
50% less than a 4 kW radar
Power consumption in standby is only 1.6 W
The BroadBand radar has no magnetron to heat!

33
Not Considered in the Report
The very low TX power of the BroadBand radar will often not trigger Racons and SARTs.
Racons are ’active radar reflectors’ on some major buoys used mainly by commercial vessels for long distance radar navigation.
The BroadBand radar cannot be used as the primary radar for rescue vessels, but serves as an outstanding no. 2 radar for close range search.

34
Additional Benefits
No 30 m blind spot at centre (mainbang)
Easy to operate. No tuning or adjusting required
Very low sidelobe effects
Totally safe, 0.1 W TX – install anywhere
No magnetron that wears out over time
Easy to install – 9 mm cable and very small connector
Easy to dismantle – external connector at radome

Thank you
Questions?

Digital Radar Processing and the New Low Power Radars

by British Marine Electronic Association on Dec 15, 2010

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