10. Secondary Sensors 



Requirements for secondary sensors stated by applications teams 

 are as follows: 



a. Renewable Land Resources 



The inclusion of a visible and infrared (VIR) sensor is a 

 priority item. The combination of data acquired by the 

 SAR and VIR sensors will increase the accuracy and 

 reliability of both types of data obtained. 



b. Nonrenewable Land Resources 



Experience with data acquired from existing satellite 

 sensor systems shows that much useful geological 

 information can be obtained from visible and infrared 

 sensing devices. It is envisaged that a pushbroom, 

 visible and solar infrared scanner, having 

 switchable/tunable channels will be available by 1990, and 

 that such a system is recommended as a secondary sensor. 



c. Ice 



The inclusion of a low resolution passive microwave 

 radiometer (PMR) and/or scatterometer is mandatory if 

 hemispheric and global coverage requirements are to be 

 met. 



d. Oceans 



Within the present knowledge and experience of team 

 members, a low resolution PMR and/or scatterometer are 

 more effective than a SAR in meeting major requirements of 

 the Oceans Team. Their choice of a secondary sensor is 

 therefore obvious. 



e. Discussion 



Although none of the teams have ruled out the possible 

 value of data obtained from alternate sensors, their 

 choice of a secondary sensor is firm and indicates an even 

 split between Land Resources and the Ice/Oceans Teams. It 

 is suggested therefore that, based on technical 

 feasibility, consideration be given to the inclusion of 

 all secondary sensors requested. This does not imply that 

 there is a requirement to utilize all sensors 

 simultaneously; various combinations of instruments could 

 be activated on an as required basis. 



5-18 



