Hummingbird’s Global Navigation Satellite System (GNSS) Speed Sender provides a reliable calibration-free replacement for mechanical speed senders.

Using data received from Satellites the GNSS Speed Sender calculates three-dimensional ground speed and provides a pulsed output compatible with existing mechanical speed senders. This high-technology solution eradicates the dependency on vehicle specific parameters, thereby reducing installation time and eradicating the need for periodic calibration.


Additional Information – HMGS1A10C Rev 1-0

Designed for harsh automotive environments, the module features transient voltage protection on the supply and short circuit protected outputs.

The ability to track American GPS, Russian GLONASS and Chinese BeiDOU navigation satellites simultaneously, enhanced receiver sensitivity and active antenna result in fast time-to-first-velocity-calculation as well as the ability to operate in the harshest RF environments such as canyons and cities.

Last known position and satellite information critical to fast start-up are battery backed in case of power failure.

Three dimensional velocity calculations are accurate to 0.2km/h and pulse output rates are updated 10 times per second. The device is fully configurable and offers following features:

  • 1000 to 10,000 pulses per kilometer (ppk) settable via adjustment screw.
  • Fixed 2000, 4000, 8000 or 50,000 pulse per kilometer option.
  • Option to add back distance lost in tunnels.

The speed sender can be supplied with an external antenna (active) for challenging installations, or with an integrated antenna (passive) for cost sensitive applications.
The speed sender works equally well with speedometers calibrated in kilometers per hour or miles per hour.

GNSS Speed Sender passive is supplied in a rugged ABS plastic enclosure with provision for screw mounting when required. No antenna connector is provided as the antenna is integrated into the enclosure.

Power to the unit and pulse outputs are provided through four colour-coded wires.

Red and green LEDs are provided to give the user status information. At power on, the red LED will begin to flash at 2Hz, indicating that the unit has power and is searching for satellites. When satellites have been acquired the red LED will remain on. The green LED flashes in sympathy with the pulse output and so will flash faster as the vehicle speed increases.

  • Pulse rate: variable (1000ppk to 10 000ppk) or fixed 2000, 4000, 8000, 50,000
  • General: 56 channel tracking receiver, battery backup 12days
  • Update rate: 10Hz
  • Accuracy, horizontal: < 5m (50%), < 8 (90%)
  • Accuracy, altitude: < 10m (50%), < 16 m (90%)
  • Accuracy, velocity: < 0.06m/sec = 0.22km/h
  • Acquisitions, after loss of lock: < 2s (90%)
  • Acquisitions, first time power applied: < 38s (50%), < 42s (90%)
  • Acquisitions, temporary loss of power: < 10s (50%), < 13s (90%)
  • Operational limits, altitude: 18000m
  • Operational limits, velocity: 300km/h

Electrical Characteristics

  • Input voltage: 6V to 36V
  • Power consumption: 240mW (12V, 20mA)
  • Battery backup: 12 days
  • Output pulse: peak to peak voltage: 5V, DC 2.5V
  • Output pulse: maximum current drain: 25mA

Physical Characteristics

  • 50mm (L), 67mm (W), 21mm (H)

Environmental Specifications

  • Operating temperature: -40°C to +85°C
  • Storage temperature: -55°C to +105°C
  • Humidity: 5% to 95% R.H. non condensing at 60°C

Interface Specifications

Power and pulse output:

  • Red input voltage (6V to 35V)
  • Black ground (0V)
  • Green pulse output
  • Blue inverted pulse output